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Biomedical subjects

D E Jenne

Publications and source records attributed to D E Jenne.

At least 37 records · Page 2Linked to original sources
PubMed1997

The human guanidinoacetate methyltransferase (GAMT) gene maps to a syntenic region on 19p13.3, homologous to band C of mouse chromosome 10, but GAMT is not mutated in jittery mice.

Guanindinoacetate methyltransferase (gene symbol, GAMT) catalyses the synthesis of creatine from guanidinoacetate and S-adensylmethionine. Pathological mutations in the coding region of GAMT were recently identified in two children with symptoms of muscular hypotonia, ataxia, seizures, and abnormal extrapyramidal movements. During contig construction in the telomeric region of human chromosome 19 we identified a cosmid clone carrying the entire GAMT gene. This clone was shown to overlap with cosmids from a contig that was previously mapped to chromosome 19p13.3. The human GAMT gene has a size of about 5 kb and consists of six exons which agree with the published cDNA sequence. Since the mouse mutations jittery/hesitant are located on band C of mouse chromosome 10 in a region of conserved synteny with 19p13.3 and jittery mice exhibit ataxia and abnormal movement behaviour, the genomic sequence of GAMT was determined in wild-type and jittery mice. The coding region of the GAMT gene, however, was not mutated in these mutant mice. Our linkage and sequence data will facilitate the identification of new GAMT mutations in patients suffering from an abnormal creatine metabolism.

Amino Acid Sequence↗
PubMed1997

Cloning and functional expression of the murine homologue of proteinase 3: implications for the design of murine models of vasculitis.

Anti-neutrophil cytoplasmic autoantibodies recognizing conformational epitopes (c-ANCA) of proteinase 3 (PR3) from azurophil granules are a diagnostic hallmark in Wegener's granulomatosis (WG). Because a functional PR3 homologue has not been identified in rodents, it is difficult to assess immunopathological responses in rats or mice immunized with patients' derived c-ANCA or human PR3. Here we report the full length cDNA cloning and functional expression of murine PR3 in HMC-1 cells. Recombinant murine PR3 shows highly similar substrate specificities towards synthetic peptides and is inhibited by human alpha1-proteinase inhibitor like human PR3. However, neither human c-ANCA, rabbit sera nor mouse monoclonal antibodies to human PR3 recognize the murine homologue. Consequently, it is unlikely that disease observed in mice after immunization with c-ANCA or human PR3 is caused by pathogenic antibodies directed against mouse PR3. Recombinant human-mouse chimaeric variants will be a valuable new tool to localize the disease-specific immunodominant epitopes in human PR3.

Amino Acid Sequence↗
PubMed1997

The second case of a t(17;22) in a family with neurofibromatosis type 1: sequence analysis of the breakpoint regions.

A reciprocal t(17;22)(q11.2;q11.2) was found in a female patient with neurofibromatosis type 1 (NF1) and in her affected daughter. Sequence analysis of cloned junction fragments traversing the breakpoints allowed the identification of the structures involved in the rearrangement. Aberrant bands in Southern hybridizations of restriction enzyme-digested DNA of the patient pointed to the disruption of the NF1 gene in intron 31. Semispecific polymerase chain reaction analysis of the genomic DNA of the patient with the specific primer anchored at NF1 exon 31 was used to obtain the breakpoint-spanning fragment of the derivative chromosome 17. The intron 31 sequence turned out to be interrupted within a large irregular (AT) repeat. The chromosome 22-derived sequence of the der(17) junction fragment allowed us to identify cosmids of the corresponding region from a chromosome 22 specific cosmid library. With the support of the breakpoint-spanning cosmids, the chromosome 22 region upstream of the fragment carried by the der(17) was characterized. Primers deduced from the sequence of this upstream region were used in combination with a primer in NF1 intron 31 distal to the breakpoint on chromosome 17 to amplify the der(22) junction fragment. The structure of the junction sequences suggested that the translocation had arisen by unequal homologous recombination between (AT)-rich repeats on chromosome 22 and on chromosome 17 in intron 31 of the NF1 gene. However, our data support the assumption of additional rearrangements prior to, or in the course of, the recombination event, leading to a loss of the sequences between the involved (AT) repeats on chromosome 22. In the direct vicinity of these (AT) repeats, two members of a previously undescribed low-copy repetitive sequence have been found, copies of which are also present on human chromosome 13.

Adult↗
PubMed1996

A new isoleucine substitution of Val-20 in transthyretin tetramers selectively impairs dimer-dimer contacts and causes systemic amyloidosis.

The most frequent form of inherited amyloidoses is associated with mutations in the transthyretin (TTR) gene coding for 127-amino acid residues of four identical, noncovalently linked subunits that form a pair of dimers in the plasma protein complex. Amyloid fibrils containing the variant and to a lesser extent the wild-type form of the TTR molecule are deposited in various organs, including peripheral nerves and the myocardium, with polyneuropathy and cardiomyopathy as major clinical manifestations. So far, more than 40 distinct amino acid substitutions distributed throughout the TTR sequence over 30 positions have been found to be correlated with an increased amyloidogenicity of TTR. Most of these amyloidogenic amino acid substitutions are suspected to alter the conformation and stability of the monomer. Here we identify and characterize by protein and DNA analysis a novel amyloidogenic Val-20 to Ile mutation in a German three-generation family. The index patient suffered from severe amyloid cardiomyopathy at the age of 60. Conformational stability and unfolding behavior of the Ile-20 monomer in urea gradients was found to be almost indistinguishable from that of wild-type TTR. In contrast, tetramer stability was significantly reduced in agreement with the expected change in the interactions between the two opposing dimers via the side chain of Ile-20. Our observations provide strong evidence for the view that amyloidogenic amino acid substitutions in TTR facilitate the conversion of tetrameric TTR complexes into those conformational intermediates of the TTR folding pathway that have an intrinsic amyloidogenic potential.

Amino Acid Sequence↗
PubMed1995

Induction of MHC class I genes in neurons.

Whether neurons express major histocompatibility complex (MHC) class I genes has not been firmly established. The techniques of confocal laser microscopy, patch clamp electrophysiology, and reverse transcriptase-polymerase chain reaction were combined here to directly examine the inducibility of MHC class I genes in individual cultured rat hippocampal neurons. Transcription of MHC class I genes was very rare in neurons with spontaneous action potentials. In electrically silent neurons, transcription was noted, with expression of beta 2-microglobulin under tighter control than in class I heavy chain molecules. Surface expression of class I molecules occurred only in electrically silent neurons treated with interferon gamma. Immunosurveillance by cytotoxic T cells may be focused on functionally impaired neurons.

Action Potentials↗
PubMed1994

A large duplicated area in the polycystic kidney disease 1 (PKD1) region of chromosome 16 is prone to rearrangement.

An area of 500 kb at the proximal end of the polycystic kidney disease 1 (PKD1) region has been mapped in detail, with 260 kb cloned in cosmids. The area cloned from normal individuals contains two homologous but divergent regions each of 75 kb, including the previously described marker 26-6. Pulsed-field gel electrophoresis identified a duplication of 75 kb of this region, referred to as the OX duplication (OXdup), in three patients with PKD1. The OXdup probably arose by an unequal exchange promoted by misalignment of partially homologous areas. Study of the OXdup in a large PKD1 family showed that it segregated with PKD1 in just one-half of the family, indicating that a recent crossover had occurred between the OXdup and PKD1 and showing that it was not a PKD1 mutation. Further analysis identified an OXdup breakpoint fragment: the OXdup was subsequently identified in 2 normal individuals of 110 assayed. The finding of the OXdup and in other individuals an 11-kb deletion (OXdel) at a similar point within this duplicated area indicates that this is an unusually unstable genomic region.

Chromosome Mapping↗
PubMed1994

The human Met-ase gene (GZMM): structure, sequence, and close physical linkage to the serine protease gene cluster on 19p13.3.

Cosmid clones containing the genes for the human and murine natural killer cell serine protease Met-ase (gene symbol GZMM; granzyme M) were identified by screening human and murine cosmid libraries with rat Met-ase (RNK-Met-1) cDNA. The human gene has a size of 7.5 kb and an exon-intron structure identical to that of serine protease genes located on human chromosomes 5q11-q12, 14q11.2, and 19p13.3 that are expressed by lymphocytes, mast cells, or myelomonocyte precursors. Using cosmid DNA as a probe for fluorescence in situ hybridization, we identified the chromosomal position of human Met-ase as 19p13.3. Interphase studies with two differentially labeled probes for Met-ase and the azurocidin (AZU1), proteinase 3 (PRTN3), and neutrophil elastase (ELA2) gene cluster revealed that the distance of Met-ase from this gene cluster is in the range of 200 to 500 kb. Using differentially labeled mouse cosmid probes, we also mapped the murine gene for Met-ase to chromosomal band 10C, close to the gene for lamin B2. Thus, the Met-ase, AZU1, PRTN3, and ELA2 genes fall into an established region of homology between mouse chromosomal band 10C and human 19p13.3.

Amino Acid Sequence↗
PubMed1994

Structure of the azurocidin, proteinase 3, and neutrophil elastase genes. Implications for inflammation and vasculitis.

The granule-associated elastase homologues neutrophil elastase (NE), proteinase 3 (PR3), and azurocidin (AZU) are involved in immune defense reactions of neutrophils and monocytes. Proteinase 3 and NE contribute to the destruction and elimination of microorganisms, cleave elastin and other proteins of connective tissues, and generate chemotactic activities by forming alpha 1-proteinase inhibitor (alpha 1-PI) complexes. Azurocidin is cytotoxic to certain microorganisms and chemotactic to monocytes. All three proteins are produced and packaged into azurophil granules in large quantities during neutrophil development. The genes encoding AZU, PR3, and NE are closely clustered in this sequence within 50 kb of genomic DNA and have the same transcriptional orientation. All three genes show the same exon-intron organization as neutrophil cathepsin G, mast cell chymase 1, and the lymphocyte serine proteases, granzymes A, B, and H. The AZU-PR3-NE gene cluster was mapped to the telomeric region on the short arm of human chromosome 19 (19p13.3), whereas cathepsin G, lymphocyte granzymes B and H, and mast cell chymase 1 are organized as a separate gene cluster on chromosome 14q11.2. Neutrophil-derived serine proteases are widely regarded as pathogenic factors in degenerative and inflammatory diseases with abnormal tissue catabolism. Autoantibodies against PR3 are an obligate feature in the pathogenesis of Wegener's granulomatosis, a systemic autoimmune vasculitis. In addition, PR3 appears to regulate growth and terminal differentiation of the myelomonocyte lineage. Future investigations will clarify whether allelic variations in the AZU-PR3-NE locus predispose patients to increased degradation of elastic fibers, as in pulmonary emphysema, and to the formation of autoantibodies against PR3 in patients with Wegener's granulomatosis.

Amino Acid Sequence↗
PubMed1993

Human megakaryocytes express clusterin and package it without apolipoprotein A-1 into alpha-granules.

Clusterin, a 70-Kd disulfide-linked two-chain plasma glycoprotein circulates in blood as a high-density lipoprotein particle and is highly induced after tissue injury and tissue remodeling. In this study, peripheral blood leukocytes were assayed for clusterin expression. The protein was predominantly detectable in human platelets by immune cytochemistry. The content of clusterin was determined and amounts to 2.5 +/- 1.3 micrograms/10(9) platelets, thus representing about 2% of the blood pool. Clusterin purified from human platelets had the same molecular weight as plasma clusterin under nonreducing conditions and was composed of two disulfide-linked nonidentical subunits of the same size. Both preparations were sensitive to reduction yielding the two subunits of 35 Kd. In contrast to plasma clusterin, the platelet form was not complexed to apolipoprotein A-I. By immunogold labeling, alpha-granule localization of clusterin was observed. Complete release of platelet clusterin occurred at optimal doses of A23187, phorbol myristate acetate (PMA), and thrombin. Because clusterin mRNA was detected by hybridization in situ in bone marrow-derived megakaryocytes, platelet clusterin is most likely produced and packaged into alpha-granules during megakaryocyte development.

Apolipoprotein A-I↗
PubMed1993

Human clusterin (CLI) maps to 8p21 in proximity to the lipoprotein lipase (LPL) gene.

Clusterin (gene symbol: CLI) is a post-translationally nicked, two-chain plasma and tissue glycoprotein of 80 kDa. It forms high-density lipoprotein complexes with apolipoprotein A-I in plasma, functions as an inhibitor of the cytolytic reaction of the terminal complement proteins C5 to C9, and is secreted by Sertoli cells in large amounts into the seminal fluid. By isolating and characterizing three partially overlapping cosmid clones, we have established the complete physical map of the clusterin gene which spans about 20 kb. The subchromosomal position of the clusterin gene (CLI) and the order of CLI and the lipoprotein lipase (LPL) gene were determined by fluorescence in situ hybridization. We show that CLI, previously assigned to chromosome 8, is located on 8p21 proximal to the LPL locus. Based on this localization we consider clusterin as a novel candidate gene determining susceptibility to atherosclerosis.

Arteriosclerosis↗
PubMed1993

The human granzyme A (HFSP, CTLA3) gene maps to 5q11-q12 and defines a new locus of the serine protease superfamily.

Human granzyme A (HFSP, Hanukah factor serine protease; CTLA3, cytotoxic T-lymphocyte-associated serine esterase-3), a homodimeric, trypsin-like serine protease of 60 kDa found in granules of cytolytic T cells and natural killer cells, is implicated in lymphocyte-mediated target cell lysis. It contributes to DNA fragmentation in perforin (PRF1)-lysed target cells through an unknown mechanism. We have isolated a cosmid clone for the functional gene of human granzyme A and established its complete exon-intron map of 10 kb. Using an 11-kb subfragment of the cloned genomic DNA as a probe, we have identified the chromosomal position of human granzyme A on 5q11-q12. Thus, the human granzyme A gene falls into a region of homology between human chromosome 5 and mouse chromosome 13, band D, where the mouse granzyme A gene has been located previously. The granzyme A gene is not linked to known members of the large superfamily of serine proteases.

Animals↗
PubMed1992

Three human elastase-like genes coordinately expressed in the myelomonocyte lineage are organized as a single genetic locus on 19pter.

The human neutrophil and monocyte-derived serine protease homologues neutrophil elastase (NE), proteinase 3 (PR3), and azurocidin (AZU) are involved in a variety of immune defense reactions. NE and PR3 assist in the destruction of phagocytosed microorganisms, cleave the important connective-tissue protein elastin, and generate chemotactic activities by forming alpha 1-proteinase inhibitor complexes and elastin peptides. AZU is cytotoxic to certain microorganisms and chemotactic for monocytes. All three proteins are produced and packaged into azurophil granules in large quantities during neutrophil differentiation. We have isolated several cosmid clones each of which contains the functional genes for AZU, PR3, and NE in this order. The PR3 gene is separated by 8 kilobases from the 3' end of the AZU gene and by 3 kilobases from the 5' end of the NE gene. We report a physical map of the gene cluster, its location on chromosome 19pter, and the exon-intron organization of the AZU and PR3 genes. Our fluorescence in situ hybridization studies disprove the previous chromosomal assignment of the human NE gene to 11q14. The five exons of AZU and PR3 are organized like those of NE and other granule-associated serine proteases of hematopoietic cells. NE, PR3, and AZU are coordinately downregulated in the premonocytic cell line U937 during induced terminal differentiation. The cluster-like physical organization of these genes and concerted regulation during hematopoietic differentiation suggests that they are located in a developmentally activated chromatin domain promoting high-level, cell-specific expression in the monocyte-myelocyte lineage.

Amino Acid Sequence↗
PubMed1992

The human vitronectin (complement S-protein) gene maps to the centromeric region of 17q.

Vitronectin (complement S-protein, serum-spreading factor, epibolin) is a multifunctional glycoprotein that mediates cell-to-substrate adhesion, inhibits the cytolytic action of the terminal complement cascade in vitro and binds to several serine protease inhibitors of the serpin family, viz. antithrombin III, plasminogen activator inhibitor I (PAI-1) and II (PAI-2), heparin cofactor II and protease nexin. Using high resolution fluorescence in situ hybridization, we mapped the vitronectin gene to the centromeric region of the long arm of chromosome 17 corresponding to 17q11. The location was confirmed by co-hybridization with the centromere-specific alphoid probe p17H8 (D17Z1) and by chromosome banding with 4,6-diamidino-2-phenylindole-dihydrochloride (DAPI). None of the previously mapped genes that are evolutionary related to vitronectin are located on the same chromosome.

Centromere↗
PubMed1992

Human perforin (PRF1) maps to 10q22, a region that is syntenic with mouse chromosome 10.

Perforin (PRF1) is a cytolytic, channel-forming protein of cytolytic T cells, natural killer cells, and granulated metrial gland cells and plays a crucial role in the killer cell-mediated elimination of virally infected host cells, tumor cells, and allotransplants. Two-thirds of the perforin sequence is homologous to the lytic, channel-forming complement proteins C6, C7, C8 alpha, C8 beta, and C9. Using cosmid DNA containing the PRF1 gene as a probe for fluorescence in situ hybridization, we have reevaluated its chromosomal location. Previously assigned to chromosome 17q11-q21, it has now been mapped to 10q22. The human PRF1 locus lies within a conserved synteny segment present on mouse chromosome 10, consistent with the previous chromosomal assignment of mouse perforin. The perforin locus is not linked to any of the genes of the terminal complement system.

Animals↗
PubMed1992

Clusterin: the intriguing guises of a widely expressed glycoprotein.

The glycoprotein clusterin has recently entered the scientific arena in diverse guises. It forms high-density lipoprotein complexes with apolipoprotein A-I, participates in the terminal complement reaction and serves as a granule constituent in neuronal and endocrine cells. Apically secreted, it is also found in the male reproductive tract and the tubular lumen of epithelial ducts. Thus, it may serve important functions in tissue remodelling, immune defense and transport of biologically active peptides.

Amino Acid Sequence↗
PubMed1991

Genomic organization and subchromosomal in situ localization of the murine granzyme F, a serine protease expressed in CD8+ T cells.

Granzyme F belongs to a closely related family of seven murine serine proteases stored in cytoplasmic granules of lymphoid cell populations. In contrast to the murine granzymes A to E and G, granzyme F is exclusively expressed in the CD4-CD8+ subset of peripheral T cells. To characterize the genomic sequences responsible for its highly restricted expression, we isolated a cosmid clone and sequenced a 7.5-kb genomic fragment that contains the promoter region and all five exons of the murine granzyme F gene. A TATA box sequence is located at position -25 relative to the transcription initiation site, which was determined by RNase protection. The genomic organization of granzyme F is similar to that of granzyme B and granzyme C, leukocyte elastase, cathepsin G, rat mast cell protease II, and complement factor D (adipsin). By the use of two fluorochromes for simultaneous high resolution in situ hybridization, the granzyme F gene was localized in close proximity distally from the TCR alpha-chain locus on mouse chromosome 14.

Amino Acid Sequence↗
PubMed1991

Clusterin (complement lysis inhibitor) forms a high density lipoprotein complex with apolipoprotein A-I in human plasma.

Clusterin/human complement lysis inhibitor (CLI) is incorporated stoichiometrically into the soluble terminal complement complex and inhibits the cytolytic reaction of purified complement components C5b-9 in vitro. Using an anti-clusterin affinity column, we found that an additional protein component with a molecular mass of 28-kDa co-purifies with clusterin from human plasma. We show by immunoblotting and amino acid sequencing that this component is apolipoprotein A-I (apoA-I). By using physiological salt buffers containing 0.5% Triton X-100, apoA-I is completely dissociated from clusterin bound to the antibody column. Free clusterin immobilized on the antibody-Sepharose selectively retains apoA-I from total human plasma. Delipidated apoA-I and to a lesser extent ultracentrifugation-purified high density lipoproteins (HDL) adsorbed to nitrocellulose also have a binding affinity for purified clusterin devoid of apoA-I. The isolated apoA-I-clusterin complex contains approximately 22% (w/w) lipids which are composed of 54% (mole/mol) total cholesterol (molar ratio of unesterified/esterified cholesterol, 0.58), 42% phospholipids, and 4% triglycerides. In agreement with the low lipid content, apoA-I-clusterin complexes are detected only in trace amounts in HDL fractions prepared by density ultracentrifugation. In free flow isotachophoresis, the purified apoA-I-clusterin complex has the same mobility as the native clusterin complex in human plasma and is found in the slow-migrating HDL fraction of fasting plasma. Our data indicate that clusterin circulates in plasma as a HDL complex, which may serve not only as an inhibitor of the lytic terminal complement cascade, but also as a regulator of lipid transport and local lipid redistribution.

Apolipoprotein A-I↗