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D J Gilbert

Publications and source records attributed to D J Gilbert.

At least 253 records · Page 14Linked to original sources
PubMed1994

Mouse desmocollin (Dsc3) and desmoglein (Dsg1) genes are closely linked in the proximal region of chromosome 18.

Mouse cDNA clones coding for a desmocollin and a desmoglein, desmosomal cadherins that are putative adhesion molecules of the desmosome type of cell-cell junction characteristically found in epithelial tissues, have been isolated and sequenced. From sequence comparisons with the known human and bovine desmosomal cadherins, these clones represent a mouse Dsc3 and Dsg1. By interspecific backcross analysis, these genes were found to be closely linked in the proximal region of mouse chromosome 18, a region having conserved synteny with human chromosome 18. From these results, and recently reported linkage of DSG1 and DSG2 on human chromosome 18 at 18q12.1 in a deletion panel of somatic cell hybrids, all the desmosomal cadherins genes so far examined are clustered on chromosome 18 in human and mouse, which may have implications for gene expression. We further show that the human DSC3 gene, previously reported to be located on chromosome 9, also maps to human chromosome 18.

Amino Acid Sequence↗
PubMed1994

Mapping of the syndecan genes in the mouse: linkage with members of the myc gene family.

The syndecans are a family of four cell surface heparan sulfate proteoglycans in vertebrates that mediate a variety of cell behaviors, including cell adhesion and the action of growth factors. Their core proteins contain conserved transmembrane and cytoplasmic domains but divergent extracellular regions in which only the glycosaminoglycan attachment sites are conserved. By extensive PCR analyses based on the conserved sequences, we find only four syndecan-related sequences in the mouse. These correspond to the previously described core proteins of syndecan proteoglycans from other vertebrates. We have mapped the genes for syndecan-2 to chromosome 15, syndecan-3 to chromosome 4, and syndecan-4 to chromosome 2 in the mouse. Together with the previous localization of the gene for syndecan-1 to chromosome 12, these data establish that the four syndecan genes are dispersed on different chromosomes and that each syndecan gene is located near a member of the myc gene family. Synd1 is next to Nmyc, Synd2 close to myc, Synd3 near Lmyc, and Synd4 on the same chromosome as Bmyc. The physical relationship between the members of these two gene families appears to be ancient and conserved after the two genome duplications thought to have occurred during vertebrate evolution.

Animals↗
PubMed1994

Identification of two clusters of mouse insulin-like growth factor binding protein genes on chromosomes 1 and 11.

The genes for insulin-like growth factor binding proteins (IGFBPs) encode secreted proteins that bind insulin-like growth factors I and II with high affinity and modulate their biological activities. In this report we have used interspecific backcross mapping and gene cloning to define the chromosomal locations of 4 mouse Igfbp genes. Igfbp1 and 3 are found in the proximal part of chromosome 1. In the human genome these two loci map within 20 kb of one another on chromosome 7p14-p12, and the genes are organized in a tail-to-tail configuration. Mouse Igfbp2 and 5 colocalize to a proximal region of chromosome 1 that is syntenic with human chromosome 2q33-q36, and the two genes are 5 kb apart in a tail-to-tail orientation. These results suggest an evolutionary scheme in which a primordial IGFBP gene duplicated to form a cluster that was later replicated to create second linkage group.

Animals↗
PubMed1994

The mouse and human excitatory amino acid transporter gene (EAAT1) maps to mouse chromosome 15 and a region of syntenic homology on human chromosome 5.

The gene for human excitatory amino acid transporter (EAAT1) was localized to the distal region of human chromosome 5p13 by in situ hybridization of metaphase chromosome spreads. Interspecific back-cross analysis identified the mouse Eaat1 locus in a region of 5p13 homology on mouse chromosome 15. Markers that are linked with EAAT1 on both human and mouse chromosomes include the receptors for leukemia inhibitory factor, interleukin-7, and prolactin. The Eaat1 locus appears not to be linked to the epilepsy mutant stg locus, which is also on chromosome 15. The EAAT1 locus is located in a region of 5p deletions that have been associated with mental retardation and microcephaly.

Amino Acid Transport Systems↗
PubMed1994

Characterization of human and mouse cartilage oligomeric matrix protein.

Cartilage oligomeric matrix protein (COMP) is a 524,000-Da protein that is expressed at high levels in the territorial matrix of chondrocytes. The sequences of rat and bovine COMP indicate that it is a member of the thrombospondin gene family. In this study, we have cloned and sequenced human COMP. Phylogenetic analysis using progressive sequence alignment and two parsimony-based algorithms indicates that the COMP gene and a precursor of the thrombospondin-3 and -4 genes were produced by a gene duplication that occurred 750 million years ago. An interspecific backcross mapping panel has been used to map the murine COMP gene to the central region of mouse chromosome 8. Southern blot analysis of a somatic cell hybrid DNA panel and in situ hybridization to human metaphase chromosomes indicate that the human COMP gene is located on chromosome 19 in band p13.1. These data confirm and extend the known regions of homology between human and mouse chromosomes and establish that COMP, like thrombospondin-1, -2, -3, and -4, is present in the human and mouse genomes.

Animals↗
PubMed1994

Structural features of the murine gene encoding the RI beta subunit of cAMP-dependent protein kinase.

The activation of cyclic AMP-dependent protein kinase is controlled by the regulatory (R) subunits of the holoenzyme. Here we present a characterization of the mouse RI beta subunit gene, which in contrast to other subunit genes of cyclic AMP-dependent protein kinase is expressed almost exclusively in neurons. It was determined that RI beta is relatively large with 11 exons spanning a minimum 75 kb. The mouse chromosomal locus (designated Prkar1b) was determined by interspecific backcross mapping and found to reside on the distal arm of chromosome 5. Previously, it was shown that 3.5 kb of DNA encompassing the RI beta promoter could direct neural-specific gene expression in transgenic mice. Analysis of this DNA suggests the presence of an unusually large number of binding sites for transcription factors ranging from tissue-specific regulators, immediate-early genes, and mediators of hormone action. In addition to 18 putative SP1 sites, we identified 27 consensus sequences for basic Helix-Loop-Helix, POU, and Pax family members, 5 AP1 sites, and over 40 half-sites for the superfamily of steroid hormone receptor. Gel mobility-shift assays employing brain nuclear extract and pure transcription factor protein established that many of these DNA sequences are functional in binding protein. The abundance and configuration of transcription factor binding sites within the promoter region of RI beta suggests that this gene is subject to complex modes of regulation in neurons.

Animals↗
PubMed1994

Ifg, Gli, Mdm1, Mdm2, and Mdm3: candidate genes for the mouse pg locus.

Various genes that mapped to the distal end of Chromosome (Chr) 10 were considered as possible candidates for the mouse pygmy (pg) locus. Probes derived from Ifg, Gli, Mdm1, Mdm2, and Mdm3 (Mdm2 and Mdm3 are genes that are coamplified with Mdm1 on the same double minute chromosomes in 3T3DM cells) were used for Southern analysis of DNA from wild-type mice and various pg mutants. In addition, the chromosomal locations of Ifg, Gli, Mdm1, Mdm2, and Mdm3 were determined by interspecific backcross analysis with progeny derived from matings of [(C57BL/6J x Mus spretus)F1 x C57BL/6J] mice. The mapping data indicate that the Mdm loci are linked to each other and to Ifg, pg, and Gli in the distal region of mouse Chr 10. Both the mapping data and the Southern analysis confirm that Mdm1, Mdm2, Mdm3, Ifg, and Gli are distinct from pg.

3T3 Cells↗
PubMed1994

Structural organization of the mouse glycophorin A gene.

The human glycophorin gene has been extensively studied, but information on the homologous gene from other species has been unavailable. Here, we determined the structural organization of mouse glycophorin A gene and compared it with the human gene. The mouse glycophorin gene is a single copy gene while in humans, there are two highly related genes (A and B) that were generated by homologous recombination. Chromosomal mapping indicated that the mouse gene is located in the central region of the mouse chromosome 8, which is syntenic with human chromosomes 4q28-31 where the human glycophorin A gene has been mapped. The mouse gene consists of 8 exons, while the human gene consists of 7 exons and the length of each exon is quite short except for the last exon. The last 4 exons showed extensive homology between the mouse and human genes but divergence in the 5'-exons of the two genes was high. The results suggest that glycophorin genes of mouse and human may have been generated from the same ancestor, but diverged greatly during evolution. The upstream regulatory region of the mouse gene consists of multiple motifs for DNA binding factors that may be required for its erythroid-specific expression.

Animals↗
PubMed1994

PEBP2 alpha B/mouse AML1 consists of multiple isoforms that possess differential transactivation potentials.

A murine transcription factor, PEBP2, is composed of two subunits, alpha and beta. There are two genes in the mouse genome, PEBP2 alpha A and PEBP2 alpha B, which encode the alpha subunit. Two types of the alpha B cDNA clones, alpha B1 and alpha B2, were isolated from mouse fibroblasts and characterized. They were found to represent 3.8- and 7.9-kb transcripts, respectively. The 3.8-kb RNA encodes the previously described alpha B protein referred to as alpha B1, while the 7.9-kb RNA encodes a 387-amino-acid protein, termed alpha B2, which is identical to alpha B1 except that it has an internal deletion of 64 amino acid residues. Both alpha B1 and alpha B2 associate with PEBP2 beta and form a heterodimer. The alpha B2/beta complex binds to the PEBP2 binding site two- to threefold more strongly than the alpha B1/beta complex does. alpha B1 stimulates transcription through the PEBP2 site about 40-fold, while alpha B2 is only about 25 to 45% as active as alpha B1. Transactivation domain is located downstream of the 128-amino-acid runt homology region, referred to as the Runt domain. Mouse chromosome mapping studies revealed that alpha A, alpha B, and beta genes are mapped to chromosomes 17, 16, and 8, respectively. The last two genes are syntenic with the human AML1 on chromosome 21q22 and PEBP2 beta/CBF beta on 16q22 detected at the breakpoints of characteristic chromosome translocations of the two different subtypes of acute myeloid leukemia. These results suggest that previously described chimeric gene products, AML1/MTG8(ETO) and AML1-EAP generated by t(8;21) and t(3;21), respectively, lack the transactivation domain of AML1.

Amino Acid Sequence↗
PubMed1994

Stat4, a novel gamma interferon activation site-binding protein expressed in early myeloid differentiation.

Interferon regulation of gene expression is dependent on the tyrosine phosphorylation and activation of the DNA-binding activity of two related proteins of 91 kDa (STAT1) and/or 113 kDa (STAT2). Recent studies have suggested that these proteins are substrates of Janus kinases and that proteins related in STAT1 are involved in a number of signalling pathways, including those activated in myeloid cells by erythropoietin and interleukin-3 (IL-3). To clone STAT-related proteins from myeloid cells, degenerate oligonucleotides were used in PCRs to identify novel family members expressed in myeloid cells. This approach allowed the identification and cloning of the Stat4 gene, which is 52% identical to STAT1. Unlike STAT1, Stat4 expression is restricted but includes myeloid cells and spermatogonia. In the erythroid lineage, Stat4 expression is differentially regulated during differentiation. Functionally, Stat4 has the properties of other STAT family genes. In particular, cotransfection of expression constructs for Stat4 and Jak1 and Jak2 results in the tyrosine phosphorylation of Stat4 and the acquisition of the ability to bind to the gamma interferon (IFN-gamma)-activated sequence of the interferon regulatory factor 1 (IRF-1) gene. Stat4 is located on mouse chromosome 1 and is tightly linked to the Stat1 gene, suggesting that the genes arose by gene duplication. Unlike Stat1, neither IFN-alpha nor IFN-gamma activates Stat4. Nor is Stat4 activated in myeloid cells by a number of cytokines, including erythropoietin, IL-3, granulocyte colony-stimulating factor, stem cell factor, colon-stimulating factor 1, hepatocyte growth factor, IL-2, IL-4, and IL-6.

Amino Acid Sequence↗
PubMed1994

Expression of the mouse corticotropin-releasing hormone gene in vivo and targeted inactivation in embryonic stem cells.

Corticotropin-releasing hormone (CRH), one of the primary regulators of the hypothalamic-pituitary-adrenal (HPA) axis, exhibits abnormal regulation in pathologic states such as depression and anorexia nervosa. Analysis of the role of CRH in regulation of the HPA axis would be facilitated by the creation of animal models in which CRH gene structure and function could be manipulated. We have determined the DNA sequence of the mouse CRH gene. Using a highly sensitive reverse transcription-polymerase chain reaction method, we have found expression of CRH mRNA in adrenal, ovary, testis, gut, heart, anterior pituitary, lung, and spleen, in addition to cerebral cortex and hypothalamus. Within the spleen, CRH mRNA is localized specifically to T-lymphocytes. We mapped the chromosomal location of mouse CRH via interspecific mouse backcrosses to chromosome 3, which is not the site of any naturally occurring mutations consistent with CRH deficiency. Because of this, we inactivated a CRH allele in mouse embryonic stem (ES) cells by homologous recombination with a mutant mouse CRH gene lacking the entire coding region of preproCRH. Mice chimeric for each of two ES clones with an inactivated CRH allele are being used to generate animals with complete CRH deficiency.

Animals↗
PubMed1994

In situ localization and chromosomal mapping of the AG1 (Dmp1) gene.

Dentinogenesis is being used as a model for understanding the biomineralization process. The odontoblasts synthesize a structural matrix comprised of Type I collagen fibrils which define the basic architecture of the tissue. The odontoblasts also synthesize and deliver a number of dentin-specific acidic macromolecules into the extracellular compartment. These acidic macromolecules may be involved in regulating the ordered deposition of hydroxyapatite crystals within the matrix. AG1 is the first tooth-specific acidic macromolecule to have been cloned and sequenced. To identify which cells of the rat incisor pulp/odontoblast complex were responsible for synthesis of AG1, in situ hybridization was used. Digoxigenin labeled sense and anti-sense AG1 riboprobes were prepared. The AG1 mRNA was found to be expressed in the mature secretory odontoblasts. Neither pulp cells nor pre-odontoblasts showed any staining with the anti-sense probes. Chromosomal localization studies placed the AG1 gene on mouse chromosome 5q21, in tight linkage with Fgf5. AG1 has been renamed Dmp1 (dentin matrix protein 1) in accordance with present chromosomal nomenclature. Mouse 5q21 corresponds to the 4q21 locus in humans. This is the locus for the human tooth mineralization disorder dentinogenesis imperfecta Type II (DI-II). These data suggest that the Dmp1 gene is involved in mineralization and is a candidate gene for DI-II.

Animals↗
PubMed1994

Cloning and characterization of a mouse brain calcitonin receptor complementary deoxyribonucleic acid and mapping of the calcitonin receptor gene.

We have identified and characterized a mouse brain calcitonin receptor (CTR) complementary DNA (cDNA). This cDNA encodes a receptor protein that, after expression, has high affinity binding for salmon calcitonin (Kd approximately, 12.5 nM) and is coupled to adenylate cyclase. The binding affinity of this expressed receptor for salmon calcitonin is lower than that described for the previously cloned porcine renal and human ovarian CTRs, but is similar to that of the recently described rat brain CTR, designated the C1b form of the receptor. Analysis of the deduced structure of the mouse brain CTR reveals that it is highly related to the other CTR cDNAs that belong to a distinct family of G-protein-coupled receptors with seven transmembrane-spanning domains. The major structural feature that distinguishes the mouse cDNA clone from the other CTRs is the presence of a consecutive 111-basepair nucleotide sequence that encodes a 37-amino acid sequence which is predicted to localize to the first extracellular loop between the second and third transmembrane-spanning domains. We have mapped the CTR gene in the mouse to the proximal region of chromosome 6, which is homologous to the 7q region of human chromosome 7; only a single CTR gene was identified. Preliminary analysis of the mouse CTR gene reveals that it is complex, consisting of multiple exons separated by lengthy introns that would allow for splice variants consistent with the existence of multiple CTR isoforms predicted from the CTR cDNA clones. The differential cellular and tissue distribution of these functionally distinct CTR isoforms provides the molecular basis for the previously reported widespread distribution and functional heterogeneity of the CTR.

Amino Acid Sequence↗
PubMed1994

Identification and chromosomal mapping of a receptor tyrosine kinase with a putative phospholipid binding sequence in its ectodomain.

We have cloned a novel receptor tyrosine kinase that has an unusual ectodomain. The extracellular sequence consists of 416 amino acids and has none of the structural motifs that have been found in other receptor tyrosine kinases. The 150 amino acids in the amino terminus of the receptor is homologous to a putative phospholipid-binding sequence that is found also in other cell adhesion molecules such as the neuronal A5 antigen and coagulation factors V and VIII. The kinase domain has a short cytoplasmic tail and contains a short insert between subdomains I and II. The structure of this receptor kinase suggests that it belongs to a new family of receptors involved in cell-cell interactions. The cell adhesion kinase (Cak) is expressed at low levels in most adult tissues and expression is highest in the brain and lung. Using fluorescence in situ hybridization and interspecific backcross mapping, the Cak gene was localized to human chromosome 6 and mouse chromosome 17.

Amino Acid Sequence↗
PubMed1993

Isolation of a cDNA encoding thymic shared antigen-1. A new member of the Ly6 family with a possible role in T cell development.

We have previously characterized a novel mouse thymocyte marker, defined as thymic shared Ag-1 (TSA-1), present on both immature thymocytes and a subset of thymic medullary epithelial cells. MTS 35, a mAb specific for TSA-1, alters T cell differentiation when added to fetal thymic organ cultures, suggesting TSA-1 may be important for T cell development in the thymus. In this study, we describe the isolation of a cDNA encoding TSA-1 using transient expression of COS-7 cells and selection with MTS 35. The predicted amino acid sequence of this cDNA encodes a 15 to 17-kDa protein and the expressed protein is linked to the membrane via a phosphatidylinositol moiety. TSA-1 is transcriptionally active at various levels in all organs examined, suggesting that its role is not solely intrathymic. TSA-1 shares amino acid sequence homology to the mouse Ly6 multigene family, epidermal growth factor-like receptors, and to cobra venom neurotoxin. The Tsa-1 locus is located on chromosome 15 linked to Ly6 on the mouse genome. We also examined the effects of MTS 35 in fetal thymic organ cultures repopulated with two subsets of thymocytes representing defined stages of T cell development. Our results suggest that TSA-1 may play a role during positive selection and the transition from CD4+CD8+ thymocytes to the mature CD4+CD8- and CD4-CD8+ subsets.

Amino Acid Sequence↗
PubMed1993

Mouse MHC class I-like Fc receptor encoded outside the MHC.

In many mammalian species antibodies transmitted from the mother provide humoral immunity to the young. Maternal IgG from milk is transported across the intestinal epithelium of neonatal rats by an Fc receptor (FcRn) that comprises an alpha-chain similar to the class I Ag of the MHC and beta 2-microglobulin. Suckling mice also acquire antibodies by uptake from the gut. We made a neonatal mouse intestinal cDNA library and screened it with a probe encoding rat FcRn alpha-chain. The nucleotide and predicted amino acid sequences of the two positive clones were very similar to those of rat FcRn. Comparison of the FcRn domains to various MHC class I and CD1 molecules suggests a divergence of FcRn from MHC early in the mammalian lineage. We expressed one of these cDNA in mouse 3T3 fibroblasts. Cells that expressed the cDNA product bound the Fc fragment of IgG with the same pH dependence as neonatal rat intestinal epithelium. We detected RNA that hybridize with the mouse cDNA only in neonatal small intestine and fetal yolk sac, two tissues involved in IgG transport. These data show that the mouse cDNA code for FcRn alpha-chain. The mouse FcRn alpha-chain is similar in sequence to the class I MHC Ag, encoded on chromosome 17 in the mouse. However, we find that the mouse FcRn gene lies outside the MHC, on chromosome 7.

Amino Acid Sequence↗