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Dysregulation of the c-myc gene by chromosomal translocation in >95% of murine plasmacytomas (MPCs) is an obligatory requirement for the transformation of B lymphocytes into MPCs. However, it is still unknown whether sIg+ B cells or differentiated plasma cells are the legitimate precursor cells from which MPCs develop. To address this question, C.B-17 scid/scid (SCID) mice were reconstituted with splenic surface Ig-positive (sIg+) B lineage cells originating from BALB/cRb6.15 (B/cRb6.15) or human IL-6 transgene-congenic BALB/cRb8.12 mice (B/cRb8.12 IL-6-Tg). Six of 80 SCID mice reconstituted with B/cRb6.15 sIg+ B cells developed MPCs after pristane (2,6,10,14-tetramethylpentadecane) treatment followed by Abelson murine leukemia virus (A-MuLV) infection (incidence 7.5%) and four of 40 after pristane treatment alone (incidence 10%). Similarly, in 20 SCID mice reconstituted with B/cRb8.12 IL-6-Tg splenic sIg+ B cells the MPC incidence was 10%. Karyotype analysis revealed that all the translocations were of typical t(12;15) type and all tumors carried the Rb6.15 or Rb8.12 marker chromosome, indicating their donor cell origin. In contrast, none of the 48 SCID mice reconstituted with plasma cells obtained from the lymph nodes of B/cRb8.12 IL-6-Tg mice developed MPCs when treated either with pristane plus A-MuLV (20 mice) or with pristane alone (28 mice), although the transferred plasma cells were still functional in the recipient SCID mice 6 months after transfer. The findings indicate that the malignant transformation triggered by Ig/myc juxtaposition occurs more in immature (sIgM+) and/or mature (sIgM+/sIgD+, sIgG+ and sIgA+) B cells than in differentiated G0 or cycling plasma cells. We inferred that immature and/or mature B cells and not differentiated plasma cells are most likely the principal source of precursor cells from which the typical t(12;15) MPCs develop.

In 1986 an albino mouse with cream yellow coat color was discovered in a breeding colony of strain CAL20, which is an IgH-C congenic strain of BALB/c mice, supported by the Institute for Experimental Animals, Faculty of Medicine, Kanazawa University. Genetic analysis revealed that the cream yellow coat color phenotype was controlled by a single recessive mutant gene on chromosome 13. A preliminary study with biochemical and histologic examinations showed that cream yellow hair contained more fatty acid than unaffected normal hair and a large number of lipid droplets accumulated in parenchyma cells of the liver in mutant mice, as early as the age of 32 days old, suggesting that the cream yellow coat color was due to unusual lipid metabolism. The locus was designated cream fur locus and was given the gene symbol crf. In addition, it was found that recombination frequencies in the vicinity of the region of the crf locus were markedly different between male and female meiosis.

The juvenile visceral steatosis (JVS) mouse exhibits hereditary systemic carnitine deficiency and develops cardiac hypertrophy. The aim of this study was to clarify the characteristics of cardiac hypertrophy in the JVS mouse. Total carnitine content in JVS mouse heart was about 10% of that of control mouse heart at 4 and 8 weeks of age. The heart weight/body weight ratio was bigger in JVS mice than that in control mice at 2 weeks of age, and this difference in ratio increased with age. The wall areas of both ventricles and septum in JVS mice were larger than those of the control mice at 2 and 8 weeks. The myocyte diameter in both ventricular walls and septum in JVS mice was longer than that of the control mice. On electron microscopy, the percent of mitochondria in the myocyte was 66% in JVS mice, and 37% in control mice. The percent of lipid fraction in JVS mice was six-fold higher than that in control mice. Total content of adenine nucleotides in JVS mouse heart was about 60% of that in control mouse heart. Adenylate energy charge in JVS mouse heart was 63 and 45% of that in the control mouse heart at 4 and 8 weeks, respectively. Overall, the cardiac enlargement observed in this animal model could be accounted for by a proportional increase in the myocyte diameter in the ventricles and septum, accompanied by an increase in mitochondria. Furthermore, this cellular growth is associated with decreases in the levels of ATP and ADP, and adenylate energy charge.

To gain an insight into the relationship between UVB-carcinogenesis and natural killer activity, we examined ultraviolet light-induced carcinogenesis in mice with high natural killer, activity (KSN) and mice with natural killer deficiency (KSN-bg). We exposed mice six times a week to three levels of daily ultraviolet B (UVB) doses; 320, 160 and 0 J/m2/day. During the latency period of skin tumor development in KSN mice, we detected no suppression of the natural killer activity at both 320 and 160 J/m2/day. Even at 1340 J/m2/day, we could not detect any significant suppression of NK activity in KSN mice. When we irradiated spleen cells in vitro, we observed NK activity suppression. Next, we compared the carcinogenic effects of UVB-irradiation on KSN and KSN-bg mice. At 320 J/m2/day, we detected no significant differences between them. In contrast, at 160 J/m2/day, KSN-bg mice showed a significantly higher rate of skin tumor induction than KSN mice (p < 0.05). Most UVB-induced tumors were squamous cell carcinoma, the rest were spindle cell carcinoma, papilloma and mixed type. Our results suggest that NK activity plays a protective role against UVB-carcinogenesis from low daily-doses of UVB-irradiation.

SCID- bg ( scid/scid, beige/beige) is a strain of double-mutant mice with impaired lymphoid development and reduced natural killer (NK) cell activity. The present study was undertaken to evaluate the usefulness of SCID- bg mice as xenograft recipients. Fetal guineapig tissues (liver, thymus, spleen) were transplanted under the kidney capsule of the mice and their serum guineapig IgG levels were measured weekly thereafter. C.B.-17- scid and anti-asialo GM1 antiserum-treated (NK-depleted) C.B.-17- scid (C.B.-17- scid-AGM1) mice that received the identical transplants were used as controls. Throughout the experimental period (1, 2, and 3 weeks after transplantation), the average serum guineapig IgG concentrations was highest in C.B.-17- scid-AGM1 mice followed by SCID- bg mice and lowest in C.B.-17- scid mice without antiserum treatment, though we could not find any statistical significance among these groups. However, SCID- bg mice always showed the smallest within-group variance (individual differencel in the serum guineapig IgG concentrations ( P 1 mice at 1,2, and 3 weeks and versus C.B.-17- scid mice at 2 weeks). The graft size was not significantly different among these three groups, but the spleen grafts in C.B.-17- scid mice contained fewer nucleate cells than the other two groups. These results indicate that the reduced NK cell activity by beige mutation is not crucial for the success of xenogenic transplantation, though SCID- bg mice may be useful as xenograft recipients with a consistent potential to retain the viability and function of engrafted tissues.

Mice homozygous for severe combined immunodeficiency (scid) mutation usually halt their thymocyte development at the CD4-CD8- double negative (DN) stage due to their inability of TCR gene rearrangement. In this study, we report that SCID-bg mice, which were originally generated by mating CB-17-scid mice with KSN-bg mice, spontaneously develop dominant CD4+ CD8+ double positive (DP) thymocytes. Their thymi were mainly composed of DN, CD4-CD8+ and DP cells, and the majority of them did not present CD3. Similarly, they lacked TCR beta expression both on cell surface and in cytoplasm, which suggests that the thymocyte development to the DP stage observed in SCID-bg mice, was independent of CD3 and TCR beta expression. In spite of significant DP thymocytes in SCID-bg mice, the histology of their thymi was not so different from those of CB-17-scid mice. Analysis of bone marrow cells in SCID-bg mice showed that the development of B lineage cells was not altered when compared with CB-17-scid mice. These findings point out the fact that thymocytes in SCID-bg mice have a peculiar characteristic compared to CB-17-scid mice, and provide evidence of TCR beta-independent development of thymocytes to the DP stage.

The juvenile visceral steatosis (JVS) mouse is a novel mutant animal for studying systemic carnitine deficiency. The importance of the model has been pointed out in carnitine-deficient cardiac hypertrophy, since cardiomyopathy has been often improved after oral carnitine therapy in human systemic carnitine deficiency. To understand the effects of carnitine deficiency on gene expression in the heart, we tried to find the genes regulated by carnitine by means of a modified differential display procedure. Carnitine palmitoyltransferase I (CPT I) was one of the isolated genes. The level of CPT I gene expression in the ventricles of the JVS mice was at least three- to sixfold that of normal mice as judged by reverse transcription-polymerase chain reaction (RT-PCR). When the JVS mice were treated with carnitine, CPT I gene expression was repressed to the level of normal mice. Therefore, the increased expression of the CPT I gene was associated with carnitine deficiency.

A carboxylesterase which shares common antigenicity with sex-influenced esterase (ES-SI) was found in both the male and the female liver of the rat but not in the following tissues: erythrocyte, heart, kidney, lung, spleen, small intestine, testis, thymus, and lymph node. Subcellular fractionation showed the esterase localizes in the microsome-rich fraction. The strain distribution of the presence or absence of the esterase in inbred rats was identical to that of ES-SI, although in adult males a considerable amount of the esterase exists, unlike ES-SI. The esterase had a higher isoelectric point than ES-SI but after neuraminidase treatment the difference disappeared, suggesting that the esterase has a sialic acid moiety. Because this esterase has different properties from those previously reported, it is proposed that it is designated liver-ES-SI. The common antigenicity and similar strain distribution between ES-SI and liver-ES-SI suggest that liver-ES-SI is a precursor molecule of ES-SI and therefore the two esterases are products of a single gene.

We analyzed carnitine profiles in C3H-H-2° strain of mouse associated with fatty liver, hyperammonemia and hypoglycemia (Koizumi et al., 1988). Carnitine levels in serum, liver and muscle of mouse with fatty liver were markedly decreased in comparison with those of control mouse (littermates without fatty liver). This is a useful animal model to analyze the role of carnitine in lipid, amino acid and carbohydrate metabolism.

We pharmacokinetically examined the effect of γ-butyrobetaine, a precursor of l-carnitine, on the change of fatty acid metabolism in juvenile visceral steatosis (JVS) mice, which have systemic l-carnitine deficiency due to lack of l-carnitine transporter activity. The concentrations of total free fatty acid (FFA), palmitic acid and stearic acid in the liver of JVS mice were significantly higher than those in wild-type mice. After intravenous administration of γ-butyrobetaine (50 mg kg−1), the concentration of l-carnitine in the plasma of JVS mice reached about twice that of the control level and levels in the brain, liver and kidney were also significantly increased, whereas those in wild-type mice hardly changed. Although the plasma concentrations of FFA in both types of mice were unchanged after administration of γ-butyrobetaine, the concentrations of palmitic acid and stearic acid were significantly decreased. In particular, the liver concentration of FFA in JVS mice was decreased to the wild-type control level, accompanied by significant decreases in long-chain fatty acids, palmitic acid and stearic acid, whereas those in wild-type mice were not changed. These results suggest that γ-butyrobetaine can be taken up into organs, including the liver, of JVS mice, and transformed to l-carnitine. Consequently, administration of γ-butyrobetaine may be more useful than that of l-carnitine itself for treatment of primary deficiency of carnitine due to a functional defect of the carnitine transporter.

Juvenile visceral steatosis (JVS) mice, which show systemic L-carnitine deficiency, may be an animal model of Reye's syndrome because of its phenotype of fat deposition and mitochondrial abnormalities in the liver. In this study, we compared the characteristics of the L-carnitine transport in isolated hepatocytes from wild-type and JVS mice. The uptake of L-carnitine by wild-type hepatocytes was saturable and the Eadie-Hofstee plot showed 2 distinct components. The apparent Michaelis constant (K(m)) and the maximum transport rate (V(max)) were 4.6 micromol/L and 59.5 pmol/15 min/10(6) cells, respectively, for the high-affinity component, and 404 micromol/L and 713 pmol/15 min/10(6) cells, respectively, for the low-affinity component. The high-affinity L-carnitine uptake occurred via an active carrier-mediated transport mechanism, which is characterized by Na(+)-, energy-, and pH-dependency. On the other hand, the high-affinity uptake was absent in JVS hepatocytes, and the values of K(m) and V(max) for the low-affinity uptake were 475 micromol/L and 557 pmol/15 min/10(6) cells, respectively. The hepatic carnitine transport properties in wild-type hepatocytes were similar to those of high-affinity mouse Octn2-transfected HEK293 cells. This study suggests that Octn2-type carnitine transporter is dysfunctional in hepatocytes of JVS mice.

We determined the activities of urea cycle enzymes in the liver of C3H-H-2o-jsv mice. The activities of all urea cycle enzymes decreased in the latter period of lactation. The activities of carbamylphosphate synthetase and ornithine transcarbamylase in some affected mice were undetectable. On the other hand, the activities of enzymes other than urea cycle enzymes were normal. We consider that the decrease in the urea cycle enzymes is caused by an abnormality in the mechanism of gene expression.

Primary systemic carnitine deficiency (SCD; OMIM 212140) is an autosomal recessive disorder characterized by progressive cardiomyopathy, skeletal myopathy, hypoglycaemia and hyperammonaemia1,2,3. SCD has also been linked to sudden infant death syndrome4. Membrane-physiological studies have suggested a defect of the carnitine transport system in the plasma membrane in SCD patients5 and in the mouse model, juvenile visceral steatosis ( jvs; ref. 6 ). Although the responsible loci have been mapped in both human7 and mouse8, the underlying gene has not yet been identified. Recently, we cloned and analysed the function of a novel transporter protein termed OCTN2 ( ref. 9 ). Our observation that OCTN2 has the ability to transport carnitine in a sodium-dependent manner prompted us to search for mutations in the gene encoding OCTN2, SLC22A5 . Initially, we analysed the mouse gene and found a missense mutation in Slc22a5 in jvs mice. Biochemical analysis revealed that this mutation abrogates carnitine transport. Subsequent analysis of the human gene identified four mutations in three SCD pedigrees. Affected individuals in one family were homozygous for the deletion of a 113-bp region containing the start codon. In the second pedigree, the affected individual was shown to be a compound heterozygote for two mutations that cause a frameshift and a premature stop codon, respectively. In an affected individual belonging to a third family, we found a homozygous splice-site mutation also resulting in a premature stop codon. These mutations provide the first evidence that loss of OCTN2 function causes SCD.

Recently, the marked decline in renal carnitine reabsorption has been thought to account fotr the systemic carnitine deficiency in juvenile visceral steatosis (JVS) mice. We have conducted a kinetic analysis using embryonic fibroblasts derived from normal, heterozygous, and homozygous jvs mice and found that the high-affinity carnitine transporter (Km = 5.5 microM), which shows Na+ and temperature dependency and stereospecificity, is defective in homozygous jvs mice. Moreover, a gene dose-dependent decrease of carnitine transport activity, which was due to a decrease in the number of the transporter molecules, was found in heterozygous jvs mice. Similar phenomena have been observed in human primary carnitine deficiency. Therefore, JVS mice may be useful for understanding this extremely rare human hereditary disorder.

Previously, we reported that a strain of severe combined immunodeficient (SCID) mice, namely SCID-bg, spontaneously develop CD4+CD8+ double positive (DP) thymocytes despite their scid mutation. In the present study, we intend to further characterize the DP thymocyte population in SCID-bg mice with Southern hybridization and flow cytometry. Southern hybridization analyses of sorted DP thymocytes in SCID-bg mice showed rearrangement of T cell receptor (TCR) beta and TCR gamma gene segments, although the expression of TCR beta and gamma delta TCR molecules was absent. The phenotype of the DP thymocytes in SCID-bg mice was CD44- heat-stable antigen (HSA)+CD25-, and they did not express CD69. Interestingly, the expression of thymus leukaemia (TL) antigen was observed in the DP thymocytes of SCID-bg mice but not in their CD4-CD8- double negative (DN) fraction. Fas expression was higher and bcl-2 expression was down-regulated in the DP thymocytes as compared to the DN thymocytes in SCID-bg mice, suggesting that they are not immortalized cells having escaped from apoptosis. Taken together, these results show that the phenotype of the DP thymocytes in SCID-bg mice is similar to that of the earliest phase of the DP thymocytes in normal mice, although the expression of the molecules in the pre-TCR complex is absent.

Juvenile visceral steatosis (JVS) mice are associated with systemic carnitine deficiency (Kuwajima, et al., 1991). In order to investigate the cause of this deficiency, we compared fibroblast carnitine transport activities in normal mice and JVS mice. The kinetic analysis showed that in formal fibroblasts, the Km and Vmax values for saturable uptake was 15.6 microM and 2.56 pmol/min/mg protein, respectively. In JVS fibroblasts, however, saturable uptake was not observed. There was no great difference in the linear component of uptake between normal and JVS fibroblasts. At the physiological concentration (50 microM) of carnitine, the fibroblast carnitine transport activity in JVS mice was decreased to 18% of that in normal mice. Thus there is hardly any carnitine transport activity in the fibroblasts of JVS mice, indicating that the JVS mouse can be regarded as an animal model of primary carnitine deficiency.

A quantitative study of the effect of carnitine deficiency on expression of glycolytic and gluconeogenic enzymes was performed using juvenile visceral steatosis mice which are systemically deficient in carnitine. The amounts of glucokinase and L-type pyruvate kinase mRNA were reduced in homozygotes, compared to heterozygotes and normal controls at 2 and 8 weeks. Liver-type phosphofructokinase, however, did not differ significantly. The abundance of fructose 1,6-bisphosphatase mRNA was unchanged at 2 and 8 weeks. The level of phosphoenolpyruvate carboxykinase mRNA was increased slightly at 2 weeks, but not at 8 weeks. A part of these changes could not be explained by the plasma glucose or insulin level. Carnitine administration restored the mRNA of these enzymes to normal levels. These results suggest that carnitine deficiency affects the expression of these liver enzymes.

Carnitine is an essential cofactor for oxidation of mitochondrial fatty acids. Carnitine deficiency results in failure of energy production by mitochondria and leads to metabolic encephalopathy, lipid-storage myopathy, and cardiomyopathy. The juvenile visceral steatosis (JVS) mouse, an animal model of systematic carnitine deficiency, inherits the JVS phenotype in autosomal recessive fashion, through a mutant allele mapped to mouse chromosome 11. As a step toward identifying the gene responsible for JVS by positional cloning, we attempted to refine the jvs locus in the mouse by detailed linkage analysis with 13 microsatellite markers, using 190 backcross progeny. Among the 13 loci tested, 5 (defined by markers D11Mit24, D11Mit111, D11Nds9, D11Mit86, and D11Mit23) showed no recombination, with a maximum lod score of 52.38. Our results implied that the jvs gene can be sought on mouse chromosome 11 within a genetic distance no greater than about 1.6 cM.

We conducted a quantitative study of the effect of carnitine deficiency on the mRNA level of carnitine palmitoyltransferase II in the liver, muscle and heart of mice with juvenile visceral steatosis, a strain that is systematically deficient in carnitine. The amount of carnitine palmitoyltransferase II mRNA was increased in liver and muscle of homozygotes, as compared with heterozygotes and normal controls, at 2, 4, and 8 wk of age. The mRNA levels of this enzyme were normalized after carnitine administration. The mRNA level of carnitine palmitoyltransferase II in the heart was increased only at 8 wk, and was not affected by carnitine administration. These results suggest that carnitine displays some effect on the mRNA level of the carnitine palmitoyltransferase II gene in liver and muscle, probably through fatty acid metabolic change.

We investigated the reabsorptional system for carnitine in the kidney to elucidate the mechanism of carnitine deficiency in juvenile visceral steatosis (jvs) mice. Jvs mice had a higher rate of carnitine excretion at 10 days after birth than the controls, in spite of having no pathological acylcarnitine excretion in the urine. In an experiment to assay the uptake of carnitine using kidney slices, homozygous mutants showed significantly lower rates of Na-dependent carnitine uptake than controls. Heterozygous mice showed values of transport activity intermediate between homozygous mutants and homozygous controls. Scatchard plots (transport activity versus transport activity/carnitine concentration) revealed that the homozygous mutants had a defect in the high affinity site (Km = 58 microM) in the Na-dependent carnitine transport system in the kidney. These results indicate that the primary defect of jvs mice is most probably related to the system for reabsorption of carnitine in the kidney.

We have reported the clinical and biochemical findings in juvenile visceral steatosis (jvs) mice with systemic carnitine deficiency. This paper is the first report about cardiomyopathy in jvs mice. Adult jvs mice (at the age of 2 3 months) show cardiac hypertrophy which is caused by enlargement of the cardiac muscle cell associated with increases of non-collagen protein and DNA content. Carnitine administration (2 mg/head, twice a day, from 1 month of age) significantly suppresses the cardiac hypertrophy, showing that carnitine deficiency plays an important role in the development of the cardiac hypertrophy. The discovery of cardiac hypertrophy in carnitine-deficient jvs mice will lead to clarification of the pathophysiology of cardiomyopathy in systemic carnitine deficiency in human beings.

Juvenile visceral steatosis (jvs) mice from the C3H-H-2° strain have markedly low levels of all the hepatic urea cycle enzymes (Imamura et al. (1990) FEBS Lett. 260, 119–121). The steady state levels of messenger RNA for the four urea cycle enzymes examined and also for albumin and serine dehydratase were severely reduced in the liver. The levels of mRNA for other liver-specific enzymes including aldolase B and phospho enol pyruvate carboxykinase did not vary significantly from normal littermates. As for extrahepatic expression of the urea cycle enzymes, only argininosuccinate synthetase in the kidney was decreased. Nuclear run-on experiments showed reduced transcription of the corresponding genes, which mostly accounts for the low mRNA levels. Furthermore, the time-course of mRNA accumulation from 5 days of age showed that the developmental induction of hepatic carbamyl phosphate synthetase and argininosuccinate synthetase mRNAs was strongly suppressed. These results suggest that jvs affects not only the regulation of the tissue-specific expression of the urea cycle enzymes but also the regulation of their developmental induction.

Sex-influenced esterase (ES-SI) is a female-specific serum esterase of rats. There are two alleles at the Es-Si locus, Es-Sia coding for ES-SI and Es-Sib, a silent allele. ES-SI was purified to electrophoretic homogeneity from the serum of adult female SI3 rats by a four-step purification. First, albumin was removed from the serum by Blue-Sepharose CL-6B affinity chromatography. Sera of rats carrying Es-Sia and Es-Sib were utilized to make two novel immunoaffinity columns. Rat anti-(ES-SI) alloantibody was obtained after the immunization of rats carrying Es-Sib with rat ES-SI-positive serum. ES-SI bound to the gel in this antibody-conjugated affinity chromatography. Simultaneously, rabbit anti-(rat serum protein lacking ES-SI) antibody was raised against ES-SI-negative rat serum and used to exclude other serum proteins. ES-SI was recovered in the flow-through fractions in this antibody-conjugated immunoaffinity chromatography, whereas the other serum proteins bound to the gel. ES-SI was selectively purified about 240-fold by combining these immunoaffinity chromatographies. This combination is a very powerful technique for purification of the protein. Finally, ES-SI was purified by preparative polyacrylamide gel electrophoresis after which it appeared as a single protein band (using silver staining) on SDS/polyacrylamide gel electrophoresis with a molecular mass of 72 kDa. In the ordinary estimation of enzyme purification, the purification of ES-SI was 30-fold at most, because the specific activity of the enzyme was calculated from the bulky esterase activity. However, ES-SI was selectively purified 2280-fold comparing its recovery to that of total protein. ES-SI exhibited a pI of 4.6 and optimum pH of 6.7. The activity of ES-SI was completely inhibited by diisopropyl fluorophosphate at 10 nM but not at all by eserine.

We introduced two mutant genes (beige; bg that induces the deficiency of natural killer (NK) activity and xid that decreases the production of immunoglobulin) into KSN nude mice with high reproductive performances. We produced KSN bg/bg(nu/nu) (KSN-bg), KSN-xid/xid(nu/nn) (KSN-xid), KSN xid/xid,bg/bg(nu/nu) (KSN-BNX) and KSN-nu/+ (KS) mice by back-cross (cross-intercross method). All strains showed as high a reproductivity rate as the parental KSN mice. KSN-xid and KSN-BNX mice had a reduced percentage of B220 positive cells in the spleens compared to KSN and KSN-bg mice, but they showed increased percentages of Thy-1 and asialo GM1 positive cells. The serum immunoglobulin concentrations of KSN-BNX were as low as KSN-xid. Both KSN-bg and KSN-BNX mice showed deficient NK activity in spleens, whereas KSN-xid mice showed an elevated NK activity. Compared to nude mice, the growth of both human tumor cell TCO-1 and BxPc-3 transplanted subcutaneously was enhanced in KSN-BNX mice. However Panc-1 cells that was rejected in nude mice was not accepted in KSN-BNX mice. Liver metastasis of human pancreatic tumor cells; Capan-1, BxPc-3 and MIAPaCa-2 were studied. No significant difference was observed in the percentage of metastasis formed mice between nude and KSN-BNX mice.

A structural locus (C-6) for the sixth component of complement in mice is assigned to chromosome 15. Three-point linkage analysis indicated that the order of loci is C-6, Gpt-1, Gdc-1, and that the map distances are 25.9±4.9 between C-6 and Gpt-1, and 36.4±5.5 between C-6 and Gdc-1. Since Gdc-1 is more distal than Gpt-1, and C-6 is 26 cM away from Gpt-1, it is estimated that the C-6 is proximal to the centromere. In addition, a new C6 form found in AKR mice is described. We propose the designation C6B for it and C-6 b for the allele encoding C6B.

SUMMARY Antigenic specificities of serum proteins from the MOL-ANJ strain of mice (a strain derived from Japanese wild mice, Mus musculus molossinus) were studied by gel precipitation with alloantisera produced by reciprocal alloimmunization between MOL-ANJ and BALB/c mice. An alloantigen which migrates immuno-electrophoretically in the β region of serum proteins has been identified. Evidence indicates that this antigenic specificity is controlled by a co-dominant autosomal gene locus designated by the symbol Sas-2. The evidence also suggests that Sas-2 is genetically different from the previously described Sus-1 which controls a serum protein in the mouse. Sas-2 was located by linkage analysis between Zdh-1 locus and Akp-1 locus on chromosome 1.

The differences in electrophoretic patterns of major urinary proteins (MUP's) due to sex, strain, and subspecies of the mouse (Mus musculus) were examined by the combined methods of agarose gel electrophoresis and immunofixation. The MUP's from the male of common laboratory inbred mice (M. m. domesticus) showed a component that was absent in females of the same strain, in addition to a strain-specific component that was determined by the Mup-1 allele carried by the strain. In MOA mice, an inbred strain from M. m. molossinus (Japanese wild mice), there was no apparent sex difference in the constitution of the components. The MUP's from this strain contained a major component that was virtually absent in those from laboratory mice, but lacked the strain-specific components of laboratory mice. In addition, the present methods revealed that both liver and serum contained MUP's consisting of components similar to those found in the urine from the same sex and strain.

An antiserum to a serum protein from female ACI rats was produced in DONRYU rats by alloimmunization. The serum protein reacting with this antiserum was shown to be a sex-innuenced esterase which is identified by zymogram techniques. Evidence for this is as follows: this protein migrated in the albumin region on agarose gel immunoelectro-phoresis and was not present in sera from mature males; all rats possessing the protein were sex-influenced esterase positive; the activity of the sex-influenced esterase in sera specifically disappeared after treatment with this antiserum. The attempt in ACI rats to produce antiserum to the esterases from DONRYU rats was unsuccessful.

The mode of larval migration (visceral larva migrans) in Toxocara canis infection was compared for BALB/c, C57BL/6, C3H/He, DBA/2, NC and BALB/c nude mice following oral infection with 400 eggs. The mean recovery of larvae from the liver on day 2 post infection (PI) was not different in terms of the strain, age or sex of the mice. The number of larvae recovered from the liver decreased in all strains on days 6, 12 and 21 PI, but the mean for BALB/c and (NC X BALB/c) F1 mice was significantly higher than that for C567BL/6, NC and BALB/c nude mice, unless the total number of larvae in the carcasses on day 21 PI was the same among those strains including athymic nude mice. The mean recovery of larvae from the liver on day 6 PI increased with age in both NC and BALB/c mice, although no sex difference was observed. From these results, it is emphasized that the age and strain of animals should be properly selected for animal experimentation with T. canis infection.

To improve the production system, the onset and the termination of reproductive life of C3Hf/HeMsNrs mice mated immediately after weaning and reared for 400 days of life, were studied. From weaning females mated with a full grown male (group A), the first litter was obtained at a mean age of 47 days, suggesting the first copulation at 26 days of age. The age of males at the first copulation was estimated to be at 44 days of age from the age giving the first litters in weanling males mated with weanling (group B) and full grown (group C) females. The sex ratio of litters delivered by young dams tended to be excess in males. The reproductive performance of dams in later life was not affected by the parturition in earlier age. The production efficiency with weaned youngs per pair during the first 200 days after mating was the highest in group A. It was found from these results that the C3H females attained their sexual maturity at 5 to 6 days after weaning, being available for breeding without any deletion in reproductive performance.

Two types of liver-specific F antigen in mice were distinguished by an immunoblotting technique after IEF of liver extracts. The IEF banding patterns consist of several bands whose pI vary from 7.57 to 8.15. One type of antigen (designated F2 antigen) showed a pattern that lacked some basic bands which are present in the pattern of the other type of antigen (designated F1 antigen). The latter type was found in AKR, CBA, C3H, DBA/2, and SM strains, while the former type was found in A, C57BL, and many other strains. Breeding experiments indicated that this variation is controlled by a single autosomal locus designated Laf (liver antigen F). Linkage analysis showed that the Laf locus is linked to the Pgm-1 locus on chromosome 5. The recombination frequency between these two loci is estimated to be 0.173 +/- 0.037. The distribution of F1 and F2 antigen types among inbred strains is concordant with that of type 1 and type 2 F antigens, which have been previously distinguished by their immunogenic differences, i.e., whether alloimmunization with the liver extracts from a given strain of mice can produce the antibody to F antigen in certain strains of mice. It is suggested, therefore, that the Laf locus may encode an allogeneic moiety of F antigen molecules.

The sex-limitation of sex-influenced esterase (ESSI) in serum of rats carrying Es-Sia allele was re-examined. ESSI was detected in immature males and females, and orchiectomized rats as well as mature females whereas ESSI in normal males rapidly disappeared with puberty. The rats orchiectomized at weaning temporarily lost ESSI around the age of sexual maturation, thereafter, ESSI reappeared. When orchiectomized rats were administered testosterone, synthesis of ESSI was suppressed as in normal adult males. Effect of ovariectomy was not recognized. The exceptional strain named SI 3 of which normal mature males have a significant level of ESSI has been established, although the level in the males is lower than that in the females of the same strain.

Genetic polymorphism of murine C3 was demonstrated by a combined use of isoelectric focusing (IEF) in thin layer polyacrylamide gel and immunofixation. All 18 inbred strains, which were originally derived from the United States, showed a single C3 band of pI 6.1. In contrast, two strains (NC and NBr) derived from the Japanese fancy mouse and a strain (MoA), which was established from Japanese wild mouse (Mus musculus molossinus), showed a single but more anodal C3 band of pI 6.0. A mixture of plasma from two different strains, one from the Japanese mouse and another from the mouse of American origin, resulted in two discrete C3 bands; neither of these two bands can be distinguished from the C3 band observed in one of the unmixed plasmas. Breeding experiments established that the pI variation of mouse C3 is inherited as an autosomal co-dominant trait controlled by a single locus. Thus, the C3 gene segregated in the classical Mendelian ratio among second generation progeny from a cross between NC and one of the American strains, B10, BALB/c, or CBA. The locus controlling the pI variation of murine C3 was designated as C3-1 locus and its linkage with other genetic markers was studied. The C3-1 locus segregated relative to Albino, Agouti, Brown, Es-1, HC, and Id-1. However, the linkage of the C3-1 locus to two loci, Ce-2 and the S region of the H-2 complex was observed. Both of these two loci are localized to chromosome 17. The distances of the C3-1 locus from Ce-2 and S were estimated as 23 and 11 centimorgans, respectively. These values imply that the C3-1 locus is located outside H-2 of the chromosome 17.

The clinical, biochemical and histopathological findings of an infantile disease occurring in the C3H-H-2° strain of mice, which has similarities with Reye's syndrome in children, is described.

Thyroidal iodine metabolism was studied in four strains of mice by use of I/sup 131/. Strain differences were found for iodine uptake, release rate from thyroid, and conversion raXio. Seasonal differences of iodine uptake were found in all strains. There was no apparent relationship between aii strains. There was no apparent relationship between these three parameters of iodine metabolism. It is assumed that the thyroid function in strain of animal can not be determined by one parameter of thyroidal iodine metabolism. The iodine uptake appeared to be influenced by environmental factors and possibly the interaction between the strain of animal and environments. (auth)

長野県西筑摩郡の農家に古くから飼養されているいわゆる木曾馬の集団は,戦争中はなはだしい雑種化を経験したが,終戦とともに,外部からの移入をほとんど完全に閉ざしている.最近の供用種雄馬の系統と産地を調査した結果,木曾馬の集団は,郡の北部に位する新開•開田の両村を種雄馬の主供給地とする単一の閉鎖集団を形作つていることが判明した.集団の有効な大きさは,1年当たり約90で安定している.これを,1世代の年数(7.7年)と種雄馬の繁殖供用期間の平均値(4.6年)を使つて換算すると,1世代当たり約150の値となる.これは集団の近交係数が,1世代に約0.33%ずつ上昇することを意味する.繁殖構造は著しいモザイク型を示し,そのため,種雄馬相互間で評価の競合が行なわれる余地は少ない.それ故,種雄馬の子の数の分布にはゆがみが少なく,分散係数は常に高い値を示している.

木曾馬を材料として,従来日本で分離され,しかも現在利用することができる5種の馬の血液型判定用抗血清(抗U1,抗U2溶血血清および抗Pf1,抗Pf2,抗Pf3凝集血清)の相互関係と,これらの抗血清によつて分類された血液型の遺伝を検討した.その結果,次の事実が確認された.1. 従来,溶血清反応によつて証明されていたU1抗原およびU2抗原は,それぞれの抗血清に補体を加えずに,凝集反応を行なうことによつても,証明される.また従来,凝集反応によつて証明されていた抗原は,抗Pf3血清に補体を加え,溶血反応を行なうことによつても,証明される.Pf2抗原は,凝集反応によつてのみ証明される.従来,それぞれの血清反応によつて,別個に分類されていたU1型とPf1型は,同一の型である.2. 各抗血清によつて分類された血液型を支配する遺伝子は,すべて常染色体上に存在する.抗原を持つ型(U1型,U2型,Pf2型,Pf3型)を支配する遺伝子は,抗原を持たない型(おのおののO型)に対して優性である.抗U1血清と抗U2血清によつて分類される4種の血液型は,3つの複対立遺伝子によつて支配される.また抗Pf2血清によつて分類される2つの血液型,および抗Pf3血清によつて分類される2つの血液型は,それぞれ1対の対立遺伝子によつて支配される.これら3つの対立遺伝子が占める座位は,たがいに独立である.

The number of mast cells in connective tissue from dorsal skin varied markedly among mouse strains. Inbred strains of mice were typed into three groups, high (NC and NZB mice), low (B6, B10, and BALB/c mice), and intermediate (C3H/He and DBA/2 mice), by their mast cell content in the skin. However, the strain differences in the number of mast cells was marginal at the age of weaning but became distinct with age. This could be explained mainly by the frequently observed clustering of mast cells in adult NC and NZB mice and the rarely observed clustering in younger mice as well as in adult B10 and BALB/c mice. The breeding experiment revealed that the difference in the number of mast cells between NC and B10 mice was controlled by a single autosomal dominant locus, for which we propose the designation Mcr (mast cell regulator). The role of the Mcr locus with regard to the frequency of the mast cell population in connective tissue is discussed.

Antigenic specificities of a serum protein from the mouse Mol-A strain (a strain derived from the Japanese wild mouse, Mus musculus molossinus) was studied by gel precipitation with alloantisera produced by reciprocal alloimmunization between Mol-A and BALB/c mice. Alloantigens which migrate immunoelectrophoretically in the alpha region of serum proteins have also been identified. The evidence indicated that this antigenic specificity is controlled by a codominant autosomal locus designated Aph-1. The evidence also suggests that the Aph-1 locus is linked to the alpha locus on chromosome 2.

A single co-dominant gene locus linked to H-2, tentatively designated C3-1 locus by us, controls allotypic variation of murine complement (C) C3 as previously described. We used this genetically determined variation of murine C3 as a marker in the probe for the synthesis of this C component in fetal and neonatal mice. Phenotypes of murine C3 were determined by a combined use of analytical isoelectric focusing and immunofixation and by antigenic analysis with alloantiserum directed to the gene product of one of the alleles at the C3-1 locus. Fetuses and neonates of inbred mice (BALB/c and NC strains), F1 hybrids, and backcross progeny express the same C3 phenotype as the one observed in adult mice of the corresponding C3 genotype. No evidence for the occurrrence of “fetal C3” in fetal mice was obtained. Furthermore, allotypic differences of C3 between mother and fetus or neonates provide evidence that murine C3 is synthesized by fetus or neonate and is not transferred from mother transplacentally nor via colostrum. In summary, mice synthesize C3 according to the allelic structural gene(s) at the C3-1 locus even during their early developmental life.

When irradiated mice were grafted with allogeneic bone marrow, their plasma haptoglobin(Hp) significantly increased 2 weeks after grafting. To elucidate the generation of the increase of Hp in allogeneic bone marrow recipients, the relationship between the Hp levels and allograft reactions was assessed. The Hp levels of irradiated recipients, which were inoculated with allogeneic spleen cells, increased with the increase of alloantigen-sensitive units in donor cells. The positive correlation between the Hp levels and graft-versus-host reactions evaluated by spleen weight assay was also observed in unirradiated F/sub 1/ hybrid mice which received parental spleen cells. It is, therefore, suspected that the elevated Hp levels found in allogeneic-bone-marrow recipients are associated with lymphoid cell proliferation initiated by alloantigenic stimulations, and it was concluded that Hp levels in allogeneic-bone-marrow recipients provide an indicator of the degree of allograft reactions.

Immunofixation after isoelectric focusing revealed two forms of mouse C6, C6A and C6M, both of which consist of two major protein bands and one or more acidic minor bands. They were distinguishable by their different isoelectric point (pI) ranges: C6M has more acidic pI ranges (pH less than 6.2) than C6A (pH less than 6.3). C6A was found in common inbred mice of Mus musculus domesticus, while C6M was found in inbred and wild mice of M. m. molossinus (Japanese wild mice, an Asian subspecies). Breeding experiments showed that these two forms of C6 were controlled by a single codominant autosomal locus. We propose the designation C-6 for this locus with two alleles, C-6a and C-6m, which encode for C6A and C6M, respectively. Linkage analysis indicated that the locus is not closely linked to the following loci: Idh-1, agouti, Amy-1, brown, Gpd-1, Mup-1, Pgm-2, Pgm-1, albino, Hbb, Es-1, Mod-1, Sep-1, Es-3, Igh-1, beige, Es-10, Sod-1, and C-3.

To determine whether different forms of C3 degrade at different rates, we compared two strains of mice with a B10 background. The only difference was that one is C3A, while the other is C3B. These strains allow comparison of C3A and C3B without the added complication of differing C3 convertases. Sera from the two strains were incubated with zymosan and the degradation products were detected by immunofixation following electrophoresis in agarose. The rate of degradation of mouse C3B was more rapid than that of C3A. Differences in the rates of degradation could not be explained by differing concentrations of C3. We suggest that the genetic differences in C3 determine the decay rate following activation via the alternate pathway.

Structural variations of murine complement C3 are controlled by a single codominant locus. Previous report from this laboratory described production of the alloantiserum directed to one of the C3 allotypes. The second alloantiserum, specific for the gene product of the C3-1b allele, was produced in NC mice by injecting partially purified C3 of BALB/c mouse. This antiserum reacted with C3-1 B, C3-1 AB, or C3-1 BC phenotype, but it did not react with either C3-1 A or C3-1 C phenotype. By the use of this antiserum it was found that C3 in mouse plasma or serum of all of 27 inbred strains previously typed as C3-1 B by IEF are not distinguished from each other antigenically. This implies that C3 in these mice is the gene product coded for by the same allele, C3-1b. With two different alloantisera, one directed to C3-1 B, the other directed to C3-1 A, we phenotyped 106 wild mice collected from four countries in Asia (Afghanistan, Pakistan, the Philippines, and Japan). All mice trapped outside Japan, which belong to either Mus musculus bactrianus or Mus musculus castaneus, had C3-1 B phenotype. On the other hand, mice that were trapped in eight out of nine places of Japan and belong to Mus musculus molossinus subspecies are polymorphic for C3. Three C3 phenotypes were found among Japanese wild mice: C3-1 A, C3-1 B, and C3-1 AB. Based on the reactivity with two alloantisera and IEF analysis, it is now possible to identify all of C3 allotypes in mice of four subspecies of Mus musculus.