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J Trowsdale

Publications and source records attributed to J Trowsdale.

At least 235 records · Page 13Linked to original sources
PubMed1986

An isolated beta 1 exon next to the DR alpha gene in the HLA-D region.

A cosmid clone containing the DR alpha gene and a beta 1 exon of a DR beta-related gene was isolated from a human cosmid clone bank made from the consanguineous DR7 cell line MANN. No other DR beta-related exons were found on this clone. The beta 1 exon was located about 15 kb away from the DR alpha gene in a tail-to-tail (3' to 3') orientation. The exon contained several deleterious mutations: a defective splice site at the 5' end, two translational frame shifts (a 1 bp deletion and a 1 bp insertion), and three extra cysteine residues. Nucleotide and amino acid sequence comparisons of the beta 1 exon indicated that although it is substantially different from other class II beta-chain genes, it is slightly more related to DR than to any other class II gene. The DR beta-related sequence was on a DNA fragment which showed no polymorphism on a panel of cell lines with Eco RI or Pst I. These Southern blots, however, revealed a related, polymorphic sequence in the human genome. Nucleotide sequences in the intron flanking the beta 1 exon shared greater sequence homology than the beta 1 exon itself when compared with the DR beta genomic sequence. The exon may play a role in the generation of variation in expressed class II beta-chain genes and it may be a relic of a different subset of class II products.

Base Sequence↗
PubMed1986

Monoclonal antibodies to HLA-DP-transfected mouse L cells.

Mouse L cells transfected with human HLA-DP (DPw4) alpha and beta genes were used to make monoclonal antibodies in C3H mice. A polymorphic antibody, DP11.1, was obtained, as well as several monomorphic antibodies. In ELISAs, DP11.1 bound to DPw4 cells and, more weakly, to DPw2, but not DPw1, -3, -5, or -6, using HLA homozygous cells. It also bound to L-cell transfectants expressing either DPw2 or DPw4 products. From B lymphoblastoid cell lysates labeled with [35S]methionine, the antibody immunoprecipitated alpha and beta chains of a similar size to those precipitated by a well-characterized DP monoclonal antibody, B7/21.2. Immunoblotting indicated that the DP11.1 antibody was directed against the alpha chain. This result confirms partial sequence data that showed that the DP alpha chain, as well as DP beta, is polymorphic, and that DPw2 and -4 alpha chains are very similar, if not identical.

Animals↗
PubMed1985

A processed pseudogene in an intron of the HLA-DP beta 1 chain gene is a member of the ribosomal protein L32 gene family.

A sequence in an intron of the human HLA-DP beta 1 gene was identified by its homology to the gene encoding ribosomal protein L32 (rpL32). It lacked introns indicating that it was derived from a processed rpL32 mRNA transcript. A human cDNA clone encoding rpL32 was isolated and compared to this human pseudogene and to several related mouse sequences, one of which is contained in an intron of the murine dihydrofolate reductase gene. Comparison of these sequences revealed that they were more related within species than between, suggesting that they became inserted in the genome after man and mouse diverged.

Animals↗
PubMed1985

Complete nucleotide sequence of a functional HLA-DP beta gene and the region between the DP beta 1 and DP alpha 1 genes: comparison of the 5' ends of HLA class II genes.

The complete nucleotide sequence of an HLA-DP beta 1 gene and part of the adjacent DP alpha 1 gene, up to and including the signal sequence exon, were determined. The sequence of the DP beta 1 gene identified it as the DPw4 allele. The six exons of the DP beta 1 gene spanned over 11,000 bp of sequence. The arrangement of the gene was broadly analogous to genes of other class II beta chains. The beta 1 exon was flanked by introns of over 4 kb. Comparisons with published sequences of cDNA clones indicated that an alternative splice junction, at the 3' end of the gene, is used in at least one allele. Variation in choice of splice junction indicates an additional mechanism for allelic variation in class II genes. The sequence also indicated that the DP beta 1 and DP alpha 1 genes are separated by only 2 kb at their 5' ends. Comparison of the 5' ends of the DP alpha 1 and beta 1 genes with other class II sequences, including the DZ alpha gene, showed conservation of several blocks of sequences thought to be involved in control of expression. Some areas of the introns were partially conserved in the DQ beta gene, and several other intron sequences were homologous to sequences found in other unrelated genes.

Alleles↗
PubMed1985

The human HLA class II alpha chain gene DZ alpha is distinct from genes in the DP, DQ and DR subregions.

A new human HLA class II alpha gene DZ alpha was sequenced. The structure and organisation of the gene was similar to other alpha chain genes except for a particularly small intron (95 bp) after the exon encoding the alpha 2 domain, and the position of the stop codon, which was on a different exon to that encoding the cytoplasmic portion of the molecule. Comparison of the DZ alpha sequence with other class II genes showed that the gene is about as distantly related to alpha chain genes in the DP, DQ and DR subregions as they are to each other. The DZ alpha gene results in an unusually large mRNA transcript of greater than 3.0 kb, detected on Northern blots of B cell lines. From the sequence, there are no obvious features that would render DZ alpha a pseudogene, except for an unusual poly(A)+ addition signal, ACTAAA. Analysis of Northern blots shows that sequences downstream (3') of this signal are present in mature mRNA. The large transcripts are probably due to defects in the signals for processing of the mRNA transcript at the 3' end.

Amino Acid Sequence↗
PubMed1985

Structure, sequence and polymorphism in the HLA-D region.

Molecular analysis of the HLA-D region has uncovered a complex array of related genes encompassing a minimum of 6 alpha and 7 beta chain sequences. A high level of polymorphism is characteristic of the DQ alpha and beta genes, as well as DR beta. The DP genes, both alpha and beta, are also polymorphic, though to a lesser extent. The genes fit into the previously established loci: DP, DQ and DR, except for a newly-discovered sequence, DZ alpha, which is approximately equally related to all of the other alpha chain genes. Analysis of the polymorphism and evolution of the HLA-D region, by examination of the sequences, calls for several independent duplication events in the generation of this family of genes.

Base Sequence↗
PubMed1984

Linkage map of two HLA-SB beta and two HLA-SB alpha-related genes: an intron in one of the SB beta genes contains a processed pseudogene.

Three overlapping cosmid clones contain coding sequences for four HLA Class II genes, provisionally identified as two HLA-SB alpha and two HLA-SB beta genes. The genes are in the order beta, alpha, beta, alpha, inverted with respect to each other. One of the SB beta genes contains a 513 bp sequence that appears to be a processed pseudogene, flanked by direct 17 bp repeat sequences, in the intron upstream of the beta 1 exon. The pseudogene is homologous to a family of sequences of approximately 25-40 members, most of which are not on chromosome 6. A cDNA clone, highly homologous to the pseudogene, except for its 5' end, contains a normal poly(A) addition site and a poly(A) tail. The cDNA clone is homologous to a single-copy gene in both man and mouse, encoded on human chromosome 15. A search of published DNA sequences identified a mouse sequence, with about 77% similarity to the pseudogene sequence, in the negative strand of an intron in a mouse dihydrofolate reductase gene. The second SB beta gene does not contain the pseudogene sequence.

Amino Acid Sequence↗
PubMed1984

Six HLA-D region alpha-chain genes on human chromosome 6: polymorphisms and associations of DC alpha-related sequences with DR types.

Analysis of cosmid clones containing genes related to the HLA-DR alpha chain calls for at least six HLA-D region alpha-chain coding sequences in man; namely, DR alpha, DC alpha, DX alpha (very closely related to DC alpha), SB alpha 1, SB alpha 2 (two closely linked genes on the same cosmid clones), and DZ alpha. The first four genes have been described previously. SB alpha 2 and DZ alpha are recently identified genes, characterized by their unique and, from a limited study, nonpolymorphic bands when used as probes for human DNA on Southern blots. All of the genes are present in somatic cell hybrids containing a human X/6 translocation chromosome, and so they are all presumably in the HLA region. The polymorphisms in the region of the DC alpha and related DX alpha genes were studied with Southern blots of DNA from a set of mostly homozygous HLA-D-typing cell lines. With EcoRI, the band patterns for the DC alpha gene corresponded to the major cross-reactive HLA-DR serotypes associated with DC (namely MT1, -2, and -3) while the DX alpha band was invariant. Both genes were polymorphic with the enzyme Taq I. Within some DR types additional polymorphic variation was detected at the DNA level, implying the existence of subtypes. The pattern of polymorphisms for DC alpha, and to a lesser extent for DX alpha, suggests that these genes may play an important role in certain HLA-D associations with disease.

Chromosomes, Human, 6-12 and X↗
PubMed1984

Isolation and sequencing of a cDNA clone for a human HLA-ABC antigen.

A cDNA clone, pHLA-A, containing sequences specific for a human class I HLA antigen heavy chain, was isolated from a bank of clones made from partially purified HLA-ABC heavy chain mRNA from the human lymphoblastoid cell line Bristol 8 (HLA-A1, A2, B8, B16). The clone corresponded to sequence for the -COOH-terminal 117 amino acids of an HLA-ABC alpha-chain. It differed in at least 15 positions from the published HLA-B7 amino acid sequence but in only two residues when compared to the partial HLA-A2 protein sequence, and was identical to the HLA-A3 protein sequence derived from the nucleotide sequence of the gene. It also differed from some published human HLA-ABC sequences by the addition of three extra -COOH-terminal amino acids: cysteine-lysine-valine. The clone may correspond to either the HLA-A1 allele, for which independent sequence information is not available, or to HLA-A2, in which case there are possible explanations for the discrepancies. Comparison of the pHLA-A sequence with genomic HLA sequences suggests variations in splicing at the end of the protein coding region in some HLA-ABC heavy chain genes, and the use of alternative poly(A) addition sites.

Amino Acid Sequence↗
PubMed1983

The complete nucleotide sequence of the I-E alpha d immune response gene.

We have isolated and sequenced the complete murine I-E alpha immune response gene of the H-2db haplotype. The I-E alpha d gene consists of 5300 basepairs and is organized into five or possibly six exons that correspond to different domains of the alpha chain. The amino acid sequence deduced from the I-E alpha gene shows 75% homology to its human counterpart, the HLA-DR alpha chain. The absence of I-E antigen in H-2 mice is due to lack of E alpha chain synthesis. We show here that this defect is caused by a deletion in the 5' end of the I-E alpha b gene.

Amino Acid Sequence↗
PubMed1983

Molecular analysis of the HLA-D region genes.

Analysis of the amino acid sequence of the HLA-DR alpha chain and the structure of the gene encoding it have shown strong homologies to membrane proximal domains of the DR beta chain and HLA-ABC, as well as to beta 2-microglobulin. Weaker, but nevertheless apparent homologies to C kappa and C lambda immunoglobulin domains support the interpretation that these genes diverged in evolution from a primordial immunoglobulin-like domain. Cosmid clones containing sequences related to the DR alpha chain have been isolated. These sequences probably represent the SB and DC alpha genes. In addition to the alpha "genes," some of the cosmids also contain sequences related to the DR beta chain suggesting that the human HLA-D region alpha and beta genes are interspersed.

Amino Acid Sequence↗
PubMed1983

Sequences related to HLA-DR alpha chain on human chromosome 6: restriction enzyme polymorphism detected with DC alpha chain probes.

Three sets of cosmid clones--containing the HLA-DR alpha chain gene and two additional related genes--were isolated from human genomic DNA libraries by using a cDNA probe for the HLA-DR alpha chain. Southern blot analysis using DNA from somatic cell hybrids indicated that all of the clones mapped to chromosome 6. Partial sequence analysis showed that the two additional related genes were highly homologous to each other, and to the HLA-DR alpha chain, in parts of the exon that encoded the alpha 2 domain but were more divergent in intron sequences. One of the genes corresponds to the HLA-DR-related DC series. DNA probes made from this gene revealed marked restriction enzyme polymorphism when hybridized to genomic DNA from HLA-DR typed homozygous cell lines. The patterns obtained from a number of homozygous and heterozygous cell lines correlated with the HLA-DR crossreactive serotypes and also indicated that there is a further sequence in the haploid human genome that is closely homologous with the DC alpha chain sequence. One family was studied and showed the expected HLA-DR-associated inheritance of restriction enzyme patterns. No polymorphism has yet been demonstrated in restriction enzyme fragments that include the other cloned sequence, which may correspond to the SB alpha chain gene or to a novel HLA-DR-related gene. These experiments indicate that there are at least three sequences in the human genome related, but not identical, to the HLA-DR alpha chain gene.

Base Sequence↗
PubMed1982

cDNA clones coding for the heavy chain of human HLA-DR antigen.

Two cDNA clones, pDRH1 and pDRH2, containing sequences specific for human HLA-DR antigens were isolated from a bank of cDNA clones made from partially purified HLA-DR mRNA from the human lymphoblastoid cell line Maja. The clones were specific for the Mr 34,000 HLA-DR antigen glycoprotein chain. The identity of these clones was established by (i) their ability to hybridize specifically to HLA-DR mRNA in a positive selection assay; (ii) mRNA species hybridizing to the cDNA clones were expressed in B-cell but not in T-cell or fibroblast cell cultures; and (iii) a nucleotide sequence in the longer clone, pDRH2, could be translated into an amino acid sequence that is identical to the limited NH2-terminal amino acid sequence available for the purified HLA-DR antigen Mr 34,000 chain. Analysis of DNA from human, mouse, and human--mouse somatic cell hybrid lines by Southern transfer of restriction endonuclease digests indicated that the HLA-DR heavy chain is encoded in chromosome 6. This finding is compatible with the location of at least one of the HLA-D/DR heavy chain genes within the HLA region. In addition, the sequences coding for HLA-DR heavy chain appear to be present in only one or a few copies in the genome and to be relatively simple in structure.

Amino Acid Sequence↗
PubMed1982

Introduction of a human X-6 translocation chromosome into a mouse teratocarcinoma: investigation of control of HLA-A, B, C expression.

We have developed an approach to human developmental biology which exploits somatic cell genetics. With this system we have examined the production of the HLA-A,B,C antigens, A human-mouse somatic cell hybrid was constructed which contained a human X-7 chromosome translocation carrying the HLA region; this hybrid was used as a donor of the X-6 translocation in the technique of microcell transfer. The X-6 chromosome recipient was the mouse embryonal carcinoma cell line PCC4. The microcell hybrid MCP-6 retained the embryonal carcinoma phenotype as judged by shape and absence of H-2 expression. Nonetheless, the expression of the HLA-A,B,C genes was not extinguished. HLA-A,B,C antigen production of the cell surface, however, was not detected because this hybrid apparently could not make beta 2-microglobulin.

Animals↗
PubMed1982

The ppp(A2'p)nA and protein kinase systems in wild-type and interferon-resistant Daudi cells.

Daudi cells, a human lymphoblastoid line, are exceptionally sensitive to the growth inhibitory effects of interferon, 1 unit/ml being sufficient to inhibit cell growth. In addition, interferon treatment of these cells severely inhibits the incorporation of exogenous thymidine into DNA and causes cells to accumulate in the G1(G0) at the expense of the S phase of the cell cycle. The possible involvement of ppp(A2'p)nA(n = 2 to less than or equal to 4) in these effects has been investigated. No (less than 1 nM) ppp(A2'p)nA or (A2'p)nA or alternative products of the ppp(A2'p)nA synthetase [e.g. NAD (2'pA)2] were detected in interferon-treated cells. In addition no evidence was obtained for the occurrence of ppp(A2'p)nA-mediated ribosomal RNA cleavage in these cells even after several days of treatment with relatively high doses of interferon. A line of Daudi cells which is resistant to all three of the above effects of interferon was selected. The wild type and resistant lines were compared with respect to the ppp(A2'p)nA and interferon and double-stranded RNA (dsRNA)-mediated protein kinase systems. The resistant line was not receptor-negative as it responded to interferon by the production of elevated levels of the ppp(A2'p)nA synthetase similar to those observed in extracts from wild-type cells. There was no detectable difference between the lines in the levels of the (2'-5')phosphodiesterase responsible for the degradation of ppp(A2'p)nA. There was, however, about a twofold increase in the ppp(A2'p)nA-dependent endoribonuclease activity in response to interferon with extracts from the wild-type but not the resistant cells. In addition, although the dsRNA-dependent protein kinase activity increased in both types of cell there was a striking reduction in the level of protein phosphorylation in general in response to interferon with material from the wild-type but not the resistant cells.

2',5'-Oligoadenylate Synthetase↗
PubMed1982

Lack of expression of HLA-ABC antigens in choriocarcinoma and other human tumor cell lines.

We studied a panel of 21 human tumor and other cell lines, mainly of epithelial origin, for the expression of HLA-ABC antigens by an indirect radiobinding assay using monoclonal antibodies. Four of the lines, 2 choriocarcinomas, a breast tumor cell lin (MDA-MB-157), and a colon carcinoma (LoVo) showed no detectable reaction with the antibodies. The levels of binding in another breast tumor line (SkBr3) and a colon carcinoma line (LS174T) were much reduced. These cell lines plus some of the HLA-ABC positive lines from the panel were studied by immunoprecipitation of 35S-labeled cell extracts. Two mechanisms for alteration of the HLA-ABC antigen levels at the cell surface were apparent. In the choriocarcinomas and one breast tumor line, beta 2 microglobulin (beta 2m) was expressed but little or no HLA-A, B, or C polypeptides were synthesized. The other HLA-ABC negative lines had defects similar to that in the previously reported Burkitt's lymphoma cell line DAUDI. In these lines, HLA-ABC polypeptides were produced but did not appear at the cell surface because beta 2m was not synthesized. The absence of HLA-ABC determinants from the cell surface is presumed to afford protection against T-cell immune attack whether naturally as against the trophoblast during pregnancy or in abnormal situations against certain tumors.

Antibodies, Monoclonal↗