Search

In a previous report (Pałyga, J., Biochem. Genet. 29, 431-445, 1991), three subtypes of erythrocyte histone H1 were found to vary in a Japanese quail population. While H1.b and H1.z histones were each represented by two electromorphs differing in apparent molecular weights, a polymorphism of histone H1.a was connected with a lack of this protein in some birds. As a genetic basis for this variability was demonstrated only in H1.b, here genetic data are provided which indicate that both H1.a and H1.z are encoded by two codominant alleles at a locus. A linkage analysis of family data in 13 quail pedigrees has revealed a significant linkage between H1.a and H1.z and between H1.b and H1.z (lod scores about 12 and 5, respectively). Thus, a gene for histone H1.z is located between H1.a and H1.b in the quail genome.

Three polymorphic subtypes of erythrocyte histone H1 (H1.a, H1.b, and H1.z) were analyzed using a sodium dodecyl sulfate polyacrylamide gel in quail populations divergently selected for a high (line 1) or low (line 2) reduction in body mass following temporary food withdrawal. Both H1.b and H1.z histone alleles were found to be differently distributed in these populations during the selection period. The frequency of b1 in line 2 was approximately 1.9-2.8 times lower than in line 1 and approached the values in line 1 when the selection was suspended. Similarly, the frequency of allele z2 at locus H1.z increased significantly (about 1.6-2.3 times) in line 2 during selection and returned to the initial values when selection was stopped. On the other hand, allele a0 at locus H1.a was kept at relatively low levels (usually below 0.05) in both lines during selection. At that time its level was approximately three to four times lower than in a random mating control population. When selection was suspended, the frequency of a0 in line 1 increased significantly, approaching the values in the control line, and remained essentially unchanged in line 2. Thus, all three polymorphic histone H1 loci in quail responded through changes in allele frequencies to the breeding selection, which was directed at the amount of body weight loss upon transient starvation. It seems that either H1 histone locus could be linked to loci controlling the rate of body weight reduction following starvation or weight loss during fasting might be influenced by a panel of H1 histone alleles that can contribute to functional differences in avian chromatin.

Calpain activity was determined by western blot analysis of steady-state concentrations of m-calpain (calpain requiring millimolar Ca2+ for activation) and also by northern blot analysis of steady-state concentrations of mRNA encoding m-calpain in three lines of quail: a random-bred control line (RR) and two lines selected for body weight, one for increased body weight (LL) and another for decreased body weight (SS). The m-calpain activities in skeletal muscle were higher in the SS line and lower in the LL line. From western blot analysis, enzyme levels of calpain were almost the same for all three lines. At the level of gene expression, the mRNA concentration encoding m-calpain was higher in the LL and lower in the SS line. These results suggest that the regulation of calpain activity in skeletal muscle is a three-step process, regulation at the transcription level, regulation at the enzyme level, and regulation of the activation of calpain.

Histone H1 from erythrocytes of Japanese quail was resolved in a sodium dodecyl sulfate (SDS)-polyacrylamide gel into five fractions differing in apparent molecular weights. A polymorphism of histone H1.1, H1.2, and H1.3 bands was detected among quail individuals. While some birds possessed either a high (phenotype .3+) or a low (phenotype .3+/.3-) level of H1.3, at least half of the quail population lacked this H1 band (phenotype .3-). Appropriate genetic crosses demonstrated that H1.3 behaved as though it was coded by a gene with two codominant alleles at an autosomal locus. Using two-dimensional polyacrylamide gel electrophoresis (acid-urea followed by SDS gels), it was found that birds .3+ contained polypeptides H1.b1 and H1.b'1; birds .3-, polypeptides H1.b2 and H1.b'2 with lower apparent molecular weights; and birds .3+/.3-, both types of polypeptides in equal proportions. The H1.b2 + H1.b'2 complement was not discernible in SDS gels, for it migrated together with H1.c' within band H1.4. It was found that a small number of birds lacking the H1.2 band in SDS gels failed to express histone H1.a. Since birds with phenotype .2- with a defective allele of the gene H1.a were simultaneously lacking the H1.3 band, it seems that the imperfect allele of the H1.a gene might be closely linked to the alleles producing H1.b2 + H1.b'2.

A chymotrypsinogen showing the phenotype AA of chymotrypsin was purified from quail pancreas, and its chromatographic behavior, molecular weight, and electrophoretic mobility were very similar to those of another chymotrypsinogen, showing the aa phenotype of chymotrypsin. However, after activation, this chymotrypsinogen from AA showed band 5 of chymotrypsin, while the other chymotrypsinogen from aa did not. Peptide mapping demonstrated that the molecular structures of the two chymotrypsinogens are different. It was recognized that chymotrypsin variants result from activated products of different molecular structures of chymotrypsinogens.

A genetic variation was found in pancreatic proteinase of Japanese quail. In eight bands of proteinase isozymes, the variation of band 5 (presence or absence) was detected among quails. Band 5 was identified as a chymotrypsin. The presence and absence of band 5 are controlled by a pair of allelic genes (Prt-5A and Prt-5a) on an autosomal locus, and gene Prt-5A, causing expression of band 5, is dominant to gene Prt-5a, a null allele for band 5. Zymograms of proteinases and their zymogens were also compared; no variation of chymotrypsinogen; corresponding to chymotrypsin Prt 5 were detected. It is suggested that the Prt-5 variant of chymotrypsin may be formed during activation of chymotrypsinogen.

The validation of the urinary excretion of N tau-methylhistidine (N tau-MH) by quail as an index of the muscle protein turnover rate was tested using the criterion of the rate of recovery of radioactivity in urine following an intraperitoneal dose of L-[3-14C] methylhistidine. A genetic study on muscle protein turnover in quail was conducted using three genetically diverse lines (LL, large body size; SS, small body size; RR, random-bred control line) selected for body size. When L-[3-14C] methylhistidine was administered to 20-week-old male and female coturnix quail by direct intraperitoneal injection, approximately 90% of the L-[3-14C] methylhistidine was recovered by 96 hr postinjection. Recoveries were low in the egg and muscle. These results show that N tau-MH released from myofibrillar protein is not reutilized and the excretion of N tau-MH is a satisfactory index of muscle protein breakdown. In all lines, the amount of urinary N tau-MH excretion and fractional synthesis (Ks) and degradation (Kd) rates at the high growing period were higher than those at the low growing period. The Ks and Kd are significantly different among selected lines at both 3 and 6 weeks of age. At 3 weeks of age, the fractional rate of synthesis of the LL line (13.2%/day) was higher than that of the RR line (11.5%/day), whereas the SS (8.1%/day) was lower than that of the RR line (11.5%/day). The fractional rates of degradation of both the LL line (4.1%/day) and the SS line (5.6%/day) were lower than that of the RR line (7.0%/day) at 3 weeks of age. From these results, it was recognized that selection for body size gave rise to the changes in the muscle protein turnover rate.

Chicken fetal-leukemic antigen (CFA) is an oncodevelopmental antigen present on embryonic and neonatal chicken peripheral red blood cells (RBCs) but is not restricted to fetal stages of development in other avian species. Crosses between white Leghorn chickens and Japanese quail resulted in adult hybrids whose peripheral RBCs were positive for CFA. Of the four CFA determinants normally found in adult quail RBCs, only two were present on quail-chicken hybrid RBCs. Adult quail--chicken hybrid RBCs also possessed on CFA determinant associated with early development in both quail and chicken and one chicken-specific CFA determinant. Evidence is presented for the possible association of CFA-positive adult peripheral RBCs and the level of circulating reticulocytes. Crosses between pheasant and turkey (both with CFA-positive adult RBCs) resulted in hybrid adult RBCs expressing only a portion of the parental CFA determinants. Through the formation of somatic cell hybrids between adult chicken and embryonic Japanese quail RBCs, it was possible to induce the appearance of CFA determinants normally restricted to embryonic chicken RBCs. Approximately 50% of the hybrid cells showed reexpression of CFA, and this induction was both time and temperature dependent. Hybridization between RBCs of adult chicken and those of either adult Japanese quail or adult turkey failed to elicit the reexpression of chicken-specific CFA.

Fractional rates (%/day) of degradation of muscle protein were determined by measuring the output of NT-methylhistidine (NT-MH) in the excreta at 2 and 10 weeks of age in three lines of quail, a random-bred line and two lines selected for body size, one for increased and the other for decreased size. In all lines, fractional rates of degradation of muscle protein at 2 weeks of age were higher than those at 10 weeks of age. The fractional rate of degradation at 2 weeks of age was highest for the RR line, 9.1-9.2%/day. However, at 10 weeks of age, the rank order changed, and the RR line showed the lowest rate, 1.8-1.9%/day. The SS line (5.8-6.2%/day at 2 weeks and 5.8-5.9%/day at 10 weeks of age) was significantly higher than the LL line (4.1-4.2%/day at 2 weeks and 2.1-2.2%/day at 10 weeks of age). Acid protease activities in supernatants of homogenized muscle of the three lines of quail at 2 and 10 weeks of age were measured. In all lines, the acid protease activities in supernatant of homogenized muscle decreased from 2 to 10 weeks of age. At 2 weeks, the protease activity of the RR line was significantly higher than that of the LL and SS lines, which did not differ significantly. However, at 10 weeks of age, the SS line had higher activity in both sexes than the LL and RR lines. The results suggest that selection for body size brings about significant changes in both fractional degradation rate and acid protease activity in the muscle.