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J Dausset

Publications and source records attributed to J Dausset.

At least 91 records · Page 5Linked to original sources
PubMed1994

Cloning the human major histocompatibility complex in YACs.

To clone the human major histocompatibility complex (MHC), 53 YACs, with an average size of 490 kb, were isolated and characterized from the CEPH YAC library. These YACs were organized in a single large contig covering more than 4000 kb. Furthermore, a complete physical map of the previously uncloned HLA class I region was established from partial and/or total digestions of 15 YACs spanning 2000 kb. This resulted in the establishment of the first YAC contig that spans the entire MHC region and constitutes an essential step in the isolation of all of the genes present in the region.

Animals↗
PubMed1994

HLA-G mRNA forms in human trophoblasts and peripheral blood lymphocytes: potential use in prenatal diagnosis.

HLA-G limited polymorphic gene maps to the human major histocompatibility complex (MHC) class I subregion and encodes the molecule which is the only MHC class I antigen expressed on cytotrophoblast cells at the maternal-fetal interface. In this tissue, HLA-G primary mRNA is differentially spliced. We have used a sensitive hot start reverse transcriptase-polymerase chain reaction (RT-PCR) technique to investigate the expression of HLA-G gene in first trimester trophoblasts and adult peripheral blood cells. PCR amplification with HLA-G primers specific of exon 3 has enabled us to demonstrate a novel alternatively spliced form of HLA-G mRNA present in fetal first trimester trophoblasts and lacking exon 4 (HLA-G4). Cloning the whole PCR product and hybridizing recombinant bacterial colonies with specific probes has permitted evaluation of HLA-G4 vs. full length mRNA frequency at approximately 1:200. Moreover, the presence of HLA-G transcripts was found at a very weak level in adult peripheral blood lymphocytes and equally in B- and T-cell populations. These results are relevant in the context of immune tolerance and in the potential use of HLA-G transcripts as a marker for RT-PCR detection of the fetal cells in maternal as a marker for RT-PCR detection of the fetal cells in maternal blood.

Abortion, Induced↗
PubMed1994

Nonradioactive screening of glucokinase mutations in maturity onset diabetes of the young.

DNA mutations were previously identified in the glucokinase gene in 56% of French families affected with maturity onset diabetes of the young (MODY), an early onset autosomal dominant form of non-insulin-dependent diabetes mellitus (NIDDM). Mutations were found on almost all exons using the common radioactive single-strand conformation polymorphism (SSCP) technique. In this paper, we describe a non-isotopic SSCP method using the Pharmacia Biotech PhastSystem for the routine screening of new mutations in diabetic patients or in offsprings of diabetic patients. The use of the PhastSystem allowed us to easily and reproducibly optimize the electrophoretic conditions for each exon. We demonstrate the efficiency of this technique by identifying 8 mutations, 7 of which have never previously been detected, in patients referred to us for diagnostic purposes. It appears to be a sensible, easy and reliable method to improve the routine diagnosis of MODY in diabetic subjects or relatives and should be applicable to other genetic diseases.

DNA Mutational Analysis↗
PubMed1993

Dense Alu clustering and a potential new member of the NF kappa B family within a 90 kilobase HLA class III segment.

We have conducted a detailed structural analysis of 90 kilobases (kb) of the HLA Class III region from the Bat2 gene at the centromeric end to 23 kb beyond TNF. A single contig of 80 kb was sequenced entirely with a group of four smaller contigs covering 10 kb being only partly sequenced. This region contains four known genes and a novel telomeric potential coding region. The genes are bracketed by long, dense clusters of Alu repeats belonging to all the major families. At least six new families of MER repeats and one pseudogene are intercalated within and between the Alu clusters. The most telomeric 3.8 kb contains three potential exons, one of which bears strong homology to the ankyrin domain of the DNA binding factors NF kappa B and I kappa B.

Amino Acid Sequence↗
PubMed1992

Altered binding of regulatory factors to HLA class I enhancer sequence in human tumor cell lines lacking class I antigen expression.

Class I antigens encoded in the major histocompatibility complex (MHC) (HLA in man, H-2 in the mouse) play a key role in the recognition of target cells by cytolytic T lymphocytes. Tumor cells frequently do not express class I MHC molecules, which strongly suggests that down-regulation of the latter facilitates escape of tumor cells from immune surveillance. The expression of class I MHC genes is tightly regulated. An enhancer element, conserved in the promoters of mouse and human MHC genes, has been shown to be important for mouse class I MHC gene expression. At least two related regulatory factors (KBF1 and NF-kappa B) bind to this regulatory element. We have analyzed the binding of these factors in cellular extracts of 23 human tumor cell lines displaying various levels of class I mRNA and surface expression. In this panel, combined deficiency of KBF1- and NF-kappa B-like DNA-binding activities was frequent among the class I-negative cell lines and correlated with the absence of class I mRNA. A few cell lines that lack KBF1 binding activity still display NF-kappa B-like activity and express normal levels of MHC class I mRNA. These results suggest (i) that, in the absence of KBF1, NF-kappa B or a related factor promotes MHC class I gene transcription; and (ii) that a combined defect in KBF1/NF-kappa B DNA-binding activity can cause a pleiotropic defect in class I gene expression, which may facilitate tumor progression.

Antibodies, Monoclonal↗
PubMed1992

Genetic mapping of three human homologues of murine t-complex genes localizes TCP10 to 6q27, 15 cM distal to TCP1 and PLG.

Human homologues of mouse t-complex genes have been cloned and localized physically to chromosome 6p or 6q. TCP1, TCP10, and PLG are human homologues of genes located in the proximal portion of the t-complex on mouse chromosome 17. We present here results of genetic mapping of these human t-complex homologues previously localized to 6q25-q27, 6q21-q27, and 6q26-q27, respectively, by physical techniques. TCP1 and PLG do not recombine with each other and are separated from TCP10 by about 15 cM, while the corresponding mouse genes are no more than 4 cM apart. Genetic mapping with markers well localized cytogenetically places TCP1 and PLG proximal to TCP10 and localizes the latter to the cytogenetic band 6q27. It is likely that the organization of human t-complex homologues on 6q is similar to that of t haplotypes rather than that of wildtype murine chromosome 17.

Animals↗
PubMed1992

The CEPH YAC library.

Because of their large size, YACs provide is a powerful tool for physical mapping studies of complex genomes. As it will be advantageous to have genomic libraries of clones with large inserts for analyzing megabase sized regions of the human genome, we have investigated a number of parameters in order to increase the insert size of the YACs. We constructed a genomic library currently containing more than 85,000 YAC clones. Mean sizes of YACs produced at several stages of construction of the library range from 430 kb to 1,200 kb, representing 13 haploid equivalents of the human genome. This library was organized in order to allow rapid screen of YACs for large scale physical mapping of the human genome.

Chromosome Walking↗
PubMed1991

Theoretical analysis of a physical mapping strategy using random single-copy landmarks.

An approach to physical mapping is analyzed here. This procedure consists of fingerprinting random clones with single-copy landmarks extracted randomly from a region of interest. Results are presented in terms of number of contigs (sets of overlapping clones), number of isolated clones, average length of a contig, and coverage of the genome by contigs larger than a given size. (i) The expected results of an ideal project are presented. (ii) Certain problems that could influence progress of the map (variability in clone insert length, double inserts, etc.) are considered. (iii) An optimal project, which consists of a 7-fold representative library fingerprinted with an average of five sequence-tagged sites per clone, is analyzed. (iv) We present strategical considerations for the proposed approach, and a strategy that minimizes the number of laboratory tests without significant information loss is proposed: clones are arranged on a matrix and pooled according to rows and columns. A fingerprint is determined for each pool, and analysis allows retrieval of the positive clones. This method reduces the number of laboratory tests done by a factor of 160.

Chromosome Mapping↗
PubMed1991

A centromere-based genetic map of the short arm of human chromosome 6.

A genetic map of the short arm of chromosomes 6 (6p) has been constructed with 20 genetic markers that define 16 loci, including a locus at the centromere. The 40 CEPH families and, for 4 loci, 13 additional Utah families were genotyped. All 16 loci form a single linkage group extending from near the telomeric region to the centromere, covering 159 cM (Haldane) on the female map and 94 cM on the male map. Sex differences in recombination frequencies are noted for the 6p map, with an excess occurring in males at the distal end. The genetic order of loci is consistent with their physical localization on 6p. Proximal to the three most distal loci on the map, markers are especially dense, providing an extended region on 6p useful for localizing genes of interest.

Blotting, Southern↗
PubMed1990

Heterogeneity of HLA genetic factors in IDDM susceptibility.

The association of certain HLA-D alleles with insulin-dependent diabetes mellitus (IDDM) is well known. One hundred and sixty-one non-related diabetic individuals and 142 non-related healthy controls were typed for the HLA DR-DQw-Dw association, using a restriction fragment length polymorphism (RFLP) typing method that combines three probe/enzyme systems: DRB/Taq I, DQB/Taq I, and DQB/Bam HI. Comparison of frequencies in both diabetics and controls confirms previous results in terms of HLA class II and IDDM association. Moreover, we have found that DR3/3 heterozygous individuals are more susceptible to IDDM when they are also Dw25 (associated with B18) than when they are Dw24 (associated with B8). Using oligonucleotide dot-blot hybridizations we analyzed the HLA-DQB1 sequence of DR3,Dw24 and DR3,Dw25 homozygous individuals, and we found no difference at position 57 between these two DR3-carrying haplotypes. This observation points to the heterogeneity of HLA genetic factors in IDDM susceptibility.

Alleles↗
PubMed1990

Excess of maternal HLA-DR3 antigens in HLA DR3,4 positive type 1 (insulin-dependent) diabetic patients.

The susceptibility determinants of Type 1 (insulin-dependent) diabetes mellitus are known to be associated with both HLA-DR3 and DR4. In our study we wished to determine if the parental origin of these antigens could influence susceptibility to the disease. We analysed the inheritance of DR3 and DR4 haplotypes from the father or mother (DR3p, DR4p, DR3m and DR4m, respectively), in the index cases and in the affected and non-affected siblings of 246 diabetic simplex and 41 multiplex families without affected parents. An independent series of 80 multiplex families (GAW 5) was also studied. Among the DR3,4 positive index cases and affected siblings, the paternal and maternal DR3 and DR4 antigens were not distributed randomly: 62% and 72%, respectively, had received DR4 from their father and DR3 from their mother (DR4p/DR3m), while only 38% and 28%, respectively, had received a paternal DR3 together with a maternal DR4 (DR3p/DR4m). This differed significantly from the 50% expected ratio (p less than 0.01) and was not observed in unaffected siblings. No excess of maternal DR3 in the absence of DR4 and no excess of paternal DR4 in the absence of DR3 were observed. The finding suggests that some maternal DR3 related event (presumably during pregnancy) might play an enhancing role in the pathogenesis of Type 1 diabetes. It also implies that siblings with both DR4p and DR3m have a significantly higher risk for disease than those with DR3p and DR4m.

Adult↗
PubMed1990

Construction and characterization of a yeast artificial chromosome library containing seven haploid human genome equivalents.

Prior to constructing a library of yeast artificial chromosomes (YACs) containing very large human DNA fragments, we performed a series of preliminary experiments aimed at developing a suitable protocol. We found an inverse relationship between YAC insert size and transformation efficiency. Evidence of occasional rearrangement within YAC inserts was found resulting in clonally stable internal deletions or clonally unstable size variations. A protocol was developed for preparative electrophoretic enrichment of high molecular mass human DNA fragments from partial restriction digests and ligation with the YAC vector in agarose. A YAC library has been constructed from large fragments of DNA from an Epstein-Barr virus-transformed human lymphoblastoid cell line. The library presently contains 50,000 clones, 95% of which are greater than 250 kilobase pairs in size. The mean YAC size of the library, calculated from 132 randomly isolated clones, is 430 kilobase pairs. The library thus contains the equivalent of approximately seven haploid human genomes.

Cloning, Molecular↗
PubMed1990

HLA- and H-2-associated variations of intra- and extracellular magnesium content.

Erythrocyte and plasma magnesium (EMg, PMg) levels have been shown to be genetically controlled in human and mouse. The possible association of these genetic factors with the major histocompatibility complex (MHC) (HLA and H-2) was investigated. Among unrelated adult male blood donors, HLA-B35 carriers have PMg (P less than 0.01) and EMg (P less than 0.0005) levels lower than those of noncarriers, while HLA-B38 carriers exhibit a significant (P less than 0.05) increase of both PMg and EMg levels when compared to the other individuals. Furthermore, HLA identical sibs have EMg values more similar than those of HLA different sibs. In the mouse, erythrocyte (P less than 0.001), plasma (P less than 0.001), liver (P less than 0.03), and spleen (P less than 0.04) Mg contents vary significantly according to H-2, with higher values being found in H-2k than in H-2q or H-2b congenic strains. However, non-MHC genes also have an influence on erythrocyte (P less than 10(-10], plasma (P less than 10(-10], spleen (P less than 10(-5], and kidney (P less than 10(-6] Mg contents as shown by differences between H-2 identical strains, which differ by the C3H and B10 genetic backgrounds. In conclusion, genetic factors controlling intra- and extracellular Mg levels are composed of at least three components: MHC (HLA and H-2)-associated genes, non-MHC genes, and tissue factors modulating the respective importance of the first two sets of factors. The mechanisms underlying this genetic system are discussed.

Adult↗
PubMed1989

The "Sardinian" HLA-A30,B18,DR3,DQw2 haplotype constantly lacks the 21-OHA and C4B genes. Is it an ancestral haplotype without duplication?

The C4 and 21-OH loci of the class III HLA have been studied by specific DNA probes and the restriction enzyme Taq 1 in 24 unrelated Sardinian individuals selected from completely HLA-typed families. All 24 individuals had the HLA extended haplotype A30,Cw5,B18, BfF1,DR3,DRw52,DQw2, named "Sardinian" in the present paper because of its frequency of 15% in the Sardinian population. Eighteen of these were homozygous for the entire haplotype, and six were heterozygous at the A locus and blank (or homozygous) at all the other loci. In all completely homozygous cells and in four heterozygous cells at the A locus, the restriction fragments of the 21-OHA (3.2 kb) and C4B (5.8 kb or 5.4 kb) genes were absent, and the fragments of the C4A (7.0 kb) and 21-OHB (3.7 kb) genes were present. It is suggested that the "Sardinian" haplotype is an ancestral haplotype without duplication of the C4 and 21-OH genes, practically always identical in its structure, also in unrelated individuals. The diversity of this haplotype in the class III region (about 30 kb less) may be at least partially responsible for its misalignment with most haplotypes, which have duplicated C4 and 21-OH genes, and therefore also for its decreased probability to recombine. This can help explain its high stability and frequency in the Sardinian population. The same conclusion can be suggested for the Caucasian extended haplotype A1,B8,DR3 that always seems to lack the C4A and 21-OHA genes.

Blotting, Southern↗