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ERV9 is a class I family of human endogenous retroviral sequences. Somatic cell hybrid genomic hybridization experiments using a mono-chromosomal panel indicate the presence of approximately 120 ERV9 loci in the human genome distributed on most chromosomes. Fluorescence in situ hybridization (FISH) using an ERV9 cDNA probe containing gag , pol and env sequences, verified this observation and a consistent signal was found at the chromosome region 11q13.3→q13.5. By analysis of a panel of radiation hybrids, an ERV9 locus was mapped to within a 300-kbp region at the chromosome site 11q13. The marker cCLGW567 and the locus MAP3K11/D11S546 centromeric and telomeric flanked it, respectively. Northern blot analysis, using an ERV9 LTR probe, indicated that most normal tissues examined expressed low abundant ERV9 LTR driven mRNAs of various sizes. The most prominent expression was found in adrenal glands and testis. However, the level of expression varied in the same tissues among different individuals indicating that ERV9 mRNA expression probably is inducible in certain tissues or at various cell stages. Copyright © 2001 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The tentative amino acid sequence of pooled, papain-solubilized HLA antigen heavy chains has been determined. The amino acid sequence comprises 273 residues. As the structural analyses were performed on HLA antigen heavy chains comprising a mixture of several allelic forms derived from the A, B, and possibly C loci, multiple residues were encountered in several positions. However, a quantitatively dominating residue could always be easily identified. The present data suggest that the amino acid variability of the HLA-A, -B, and -C antigens is found in restricted regions of the molecule. The COOH-terminal third of the HLA antigen heavy chain appears to be less variable than other regions of the molecule. Previous work has shown that the HLA antigen heavy chain contains two immunoglobulin-like disulphide loops. The COOH-terminal third of the heavy chain was shown to be similar in primary structure to β2-microglobulin and the immunoglobulin G constant domains. [ABSTRACT FROM AUTHOR]

Purified intestine epithelial cells express la antigens as determined by immunoprecipitation and sodium dodecyl sulphate polyacrylamide-gel electropheresis. The intestimal la antigens react at least with alloantisera directed against the H-2 I-A subregion. [ABSTRACT FROM AUTHOR]

Deoxycholate-solubilized HLA antigens have been isolated from platelets and comprised a mixture of 43,000- and 39,000-dalton polypeptide chains associated with β2-microglobulin. Limited proteolysis experiments suggested that the 39,000-dalton chain is a fragment of the intact 43,000-dalton chain. Further proteolysis of the 39.000-dalton fragment yields a 33,000- dalton component. The 39,000-dalton molecule is more acidic than both the 43,000- and the 33,000-dalton chains. Differences in the amino acid compositions of the 43,000- and 39,000- dalton species demonstrate that the peptide(s) released on generation of the 39,000-dalton comcomponent are charged. The proteolytic split most probably occurs in the COOH-terminal end, which, owing to its content of charged amino acids, most probably is not integrated into the hydrocarbon matrix of the membrane. The 39,000- and 43,000-dalton components bind detergent in micellar form and can be incorporated into liposomes. The 33,000-dalton fragment has lost the ability to bind detergent micelles and is not incorporated into liposomes. [ABSTRACT FROM AUTHOR]

Papain-solubilized HLA-A,B,C antigen heavy chains have been cleaved by combined acid and CNBr treatment to yield three large fragments. A 14,000-dalton peptide comprises the NH2-terminal portion of the molecule, less a five-membered peptide. The 14,000-dalton fragment is followed in the linear sequence by a 9000-dalton peptide connected through an aspartyl-prolyl bond to the COOH-terminal 11,000-dalton fragment. The 9000- and 11,000-dalton fragments contain disulphide bridges that are immunoglobulin-like inasmuch as they encompass some fifty-five to sixty amino acid residues. The NH2-terminal portion of the HLA antigen heavy chain is devoid of cysteine. NH2-terminal amino acid sequence analyses do not reveal homologies between the 14,000- and 9000-dalton fragments, β2-microglobulin, and the constant immunoglobulin domains. However, the NH2-terminal sequence of the 11,000-dalton fragment is as homologous to β2-microglobulin and the constant immunoglobulin domains as they are to one another. [ABSTRACT FROM AUTHOR]

The genetic basis for the extensive polymorphism of major histocompatibility complex (MHC) class II molecules was investigated by statistical analysis. Nucleotide sequences of human DQA1, DQB1, DRB1, and DRB3 genes and routine Aα, Aβ, and Eβ genes were used. The results show that polymorphism is selected for in the antigen recognition site of class II molecules since replacement substitutions in this region were found to occur at a significantly higher frequency than expected in the absence of selection. In contrast, replacement substitutions are selected against in the remaining part of the first domain exon and in the second domain exon. Furthermore, comparing the sequence variability pattern among different class II α and sequences, using a variability index for each residue, showed that, with few exceptions, highly polymorphic residues occur in the antigen recognition site. There was a strong and highly significant correlation in the variability pattern in the homologous DRB/Eβ sequences but not for DQB/Aβ or DQA/Aα sequences. This difference may be related to the fact that both α and chains of DQ/A molecules are polymorphic, while only β chains of DR/E molecules vary. [ABSTRACT FROM AUTHOR]

A truncated form of the class II antigen DRα chain of the human major histoeompatibility complex was produced in bacteria. A cDNA clone encoding the intact chain was modified so that the segment encoding the signal sequence was replaced by an ATG codon and the 3′ region downstream to the part corresponding to the third exon was replaced by a stop codon. The new construct was put under the control of the Tae promoter in a bacterial expression vector. The distance between the Shine-Delgarno sequence and the initiation codon was randomized so that clones with optimal expression of the truncated DRα chain could be obtained after induced expression and immunoscreening. The truncated DR a chain was subjected to limited proteolysis with chymotrypsin, and the resulting cleavage products were analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Two fragments were visualized by western blotting. Electrophoresis in the absence and presence of reducing agents suggested that one of the proteolytic fragments contained a disulphide bridge. It is concluded that the extracellular portion of the DRα chain is composed of two compactly folded domains connected by an extended stretch of the polypeptide chain. [ABSTRACT FROM AUTHOR]

Thirty-six consecutive paediatric patients (0-16 years old) with recently contracted juvenile diabetes (IDDM) during 1982-84 were included in the study. Sera were assayed for recent or current Coxsackie B virus (CBV) infection using a specific and sensitive IgM RIA, Eighteen patients (50%) had IgM against CBV 1-5, The patients were also assayed for restriction fragment length polymorphism (RFLP) patterns with DNA probes coding for HLA-DR and DQ beta chains. The CBV-positive patients (n=18) had either RFLP patterns associated with HLA-DR 3 or 4 or HLA-DQ patterns III or IV beta. Two of the CBV negative patients had neither HLA-DR 3 nor DR 4 and four of them had neither DQ patterns III nor IV, Eleven out of 18 CBV-positive patients had HLA-DQ III and DR 3 (61%) versus 5 out of 18 (28%) of the CBV-negative patients. All 11 patients with serology positive for CBV 2,3, and 5 had HLA-DR 4 and DQ IV patterns. This was significantly (P<0.01) different from all five CBV 4-positive patients, who in contrast all had HLA-DR 3 or HLA-DQ III patterns, CBV 1-positive patients (n=2) all had HLA-DR 3, 4, and HLA-DQ III, IV patterns. Thus CBV 4 seems to be significantly associated with a different host genetic constitution from at any rate CBV 2,3, and 5, and possibly CBV 1. [ABSTRACT FROM AUTHOR]

The signal sequences of two HLA-DR β chains and the DR α chain were determined. In addition, the major part of a DC β-chain signal sequence was also elucidated. The data were obtained by combining amino acid sequence analyses of isolated α and β chains with nucleotide sequencing of four cDNA clones. All signal sequences comprise 25 amino acids or more. The two HLA-DR β-chain signal sequences are identical and exhibit only marginal homology to the DC β-chain signal sequence. No homology is apparent between α- and β-chain signal sequences. The differences in the signal sequences of the DR and DC β chains suggest that these sequences may be used to assign β chains to different loci of the human major histocompatibility complex. [ABSTRACT FROM AUTHOR]

Membrane-bound mRNA was isolated from Raji cells and enriched for message coding for the HLA-DR transplantation antigen α-chain by sucrose gradient centrifugation. Double-stranded cDNA was constructed from this mRNA fraction, ligated to plasmid pBR322, and cloned into Escherichia coli. By hybrid selection, a plasmid, pDR-α-1, able to hybridize with mRNA coding for the HLA-DR α-chain was identified. From the nucleotide sequence of one end of the insert an amino acid sequence was predicted which is identical to part of the amino-terminal sequence of an HLA-DR α-chain preparation isolated from Raji cells. This clearly shows that pDR-α-1 carries almost the complete message for an HLA-DR α-chain. From the nucleotide sequence of this plasmid it will be possible to predict the primary structure of an HLA-DR α-chain. [ABSTRACT FROM AUTHOR]

cDNA for a Βchain of HLA-DR antigens was cloned and the partial nueleotide sequence was determined. The data suggest that the fl-chain consists of approximately 230 amino acids. ot which about 200 are exposed on the cell surface. The 6-chain appears to be composed of Two exposed disulphide-containing domains. The arrangement of the disulphide loops suggests that the 5-chain is similar in structure to the HLA-A, B, C antigen subunits and the immunoglobulin chains. for the Βchain domain closest to the membrane this similarity was verified at the level of primary structure. The partial amino acid sequence of the NH2>terminal domain did not display any apparent homology to HLA-A, B, C antigens and immunoglobulins. However, the similarity established here between the two types of major histocompatibility antigen subunits and the immunoglobulin chains suggests a common ancestral origin for at least some regions of these molecules. [ABSTRACT FROM AUTHOR]

A nucleoside diphosphate kinase has been highly purified from baker's yeast, and has been obtained in a crystalline form from an ethanol‐containing medium. During short‐time incubation with [32P]ATP, the enzyme was phosphorylated to an extent of about 3–4 phosphoryl groups per mole of enzyme assuming a molecular weight of 105. This indicates an intermediate phosphorylation of the enzyme. 1‐[32P]Phosphohistidine was shown to be the dominating radioactive degradation product in an alkaline hydrolysate of the 32P‐labelled enzyme. In addition, 3‐[32P]‐phosphohistidine and Ne‐[32P]phospholysine were obtained in small amounts. The results indicate that the amino acid sequence around the reactive 1‐phosphohistidine of the yeast enzyme is different from that of human erythrocytic and bovine liver nucleoside diphosphate kinase. [ABSTRACT FROM AUTHOR]

The soluble epoxide hydrolase mRNA level in liver was increased eight-fold upon administration of the hypolipidemic drug and peroxisome proliferator clofibrate for 7 days to mice. The soluble epoxide hydrolase mRNA was back at control levels within 1-2 days after clofibrate withdrawal. The highest expression was in liver, intestine and kidney. Lower levels were found in heart and muscle and very low levels were found in testes, lung, brain and spleen. The mRNA levels were increased in liver, kidney and heart by clofibrate. [ABSTRACT FROM AUTHOR]

Vitamin A has, apart from its function in the visual pigments, general effects on several organs. Early signs of vitamin A deficiency include keratinization of epithelia and hyperkeratosis of the skin. To elucidate a generalized function for vitamin A, we have taken the approach of tracing the vitamin from its storage site in the liver via its blood transport by the retinol-binding protein (RBP) to its uptake by susceptible cells. We have also examined the intracellular occurrence of vitamin A as regards its binding to specific receptor proteins. Here we summarize data on the amino acid sequences of several vitamin A-binding proteins. The finding that CRBP and CRABP, the two intracellular proteins, are homologous to each other, to a myelin protein, and to a fatty acid-binding protein may shed light on the functions of these proteins. Retinoic acid, which binds to CRABP but not CRBP, induces differentiation of teratocarcinoma cells, This is accompanied by a lowering of the CRABP concentration, an increase of the CRBP level, and an increase in the uptake of retinol from RBP. The epidermis contains both CREP and CRABP, and their distributions are rather similar, However, in contrast to CRBP, CRABP is most abundant in cells lining the hair follicles. CRBP occurs in greatest relative amounts in the outer layers of the epidermis. Since techniques have been developed to measure CRBP and CRABP, normal and disease-affected skin may now be explored as to quantity and cellular distribution of the retinoid-binding proteins. [ABSTRACT FROM AUTHOR]