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D J Gilbert

Publications and source records attributed to D J Gilbert.

At least 127 records · Page 7Linked to original sources
PubMed1997

Cloning and expression analysis of murine phospholipase D1.

Activation of phosphatidylcholine-specific phospholipase D(PLD) occurs as part of the complex signal-transduction cascade initiated by agonist stimulation of tyrosine kinase and G-protein-coupled receptors. A variety of mammalian PLD activities have been described, and cDNAs for two PLDs recently reported (human PLD1 and murine PLD2). We describe here the cloning and chromosomal localization of murine PLD1. Northern-blot hybridization and RNase protection analyses were used to examine the expression of murine PLD1 and PLD2 ina variety of cell lines and tissues. PLD1 and PLD2 were expressed in all RNA samples examined, although the absolute expression of each isoform varied, as well as the ratio of PLD1 to PLD2. Moreover, in situ hybridization of adult brain and murine embryo sections revealed high levels of expression of individual PLDs in some cell types and no detectable expression in others. Thus the two PLDs probably carry out distinct roles in restricted subsets of cells rather than ubiquitous roles in all cells.

Amino Acid Sequence↗
PubMed1997

Peropsin, a novel visual pigment-like protein located in the apical microvilli of the retinal pigment epithelium.

A visual pigment-like protein, referred to as peropsin, has been identified by large-scale sequencing of cDNAs derived from human ocular tissues. The corresponding mRNA was found only in the eye, where it is localized to the retinal pigment epithelium (RPE). Peropsin immunoreactivity, visualized by light and electron microscopy, localizes the protein to the apical face of the RPE, and most prominently to the microvilli that surround the photoreceptor outer segments. These observations suggest that peropsin may play a role in RPE physiology either by detecting light directly or by monitoring the concentration of retinoids or other photoreceptor-derived compounds.

Amino Acid Sequence↗
PubMed1997

Neurturin, a novel neurotrophic factor, is localized to mouse chromosome 17 and human chromosome 19p13.3.

Neurturin is a potent neurotrophic factor closely related to glial cell line-derived neurotrophic factor (GDNF, 40% amino acid sequence identity) and, like GDNF, can promote the survival of numerous neuronal populations including sympathetic, nodose, and dorsal root ganglion sensory neurons. Both neurturin and GDNF signal through the Ret tyrosine kinase and require a glycosylphosphatidylinositol-linked coreceptor. Mutations in Ret and GDNF cause intestinal aganglionosis and renal dysplasia. Activating Ret mutations also cause multiple endocrine neoplasia syndromes (MEN2A and MEN2B). We have isolated mouse and human genomic neurturin clones. The sequence for preproneurturin is encoded by two exons. Mouse and human clones have common intron/exon boundaries. We have used interspecific backcross analysis to localize neurturin to mouse chromosome 17 near the Vav locus and fluorescence in situ hybridization analysis to localize human neurturin to the syntenic region of human chromosome 19p13.3.

Amino Acid Sequence↗
PubMed1997

Genomic organization and chromosomal localization of the mouse telencephalin gene, a neuronal member of the ICAM family.

Telencephalin is a cell adhesion molecule belonging to the immunoglobulin (Ig) superfamily, whose expression is restricted to subsets of neurons in the telencephalon, the most rostral segment of brain. Of all the Ig superfamily molecules so far identified, the structure of telencephalin is most closely related to those of intercellular adhesion molecules (ICAMs)-1 and -3. Here we report the cloning, characterization, and chromosomal localization of the mouse telencephalin gene (Tlcn). The Tlcn gene spanned about 6.3 kb and consisted of 11 exons. A signal peptide and individual nine Ig-like domains of telencephalin were encoded by a single exon, while the transmembrane and cytoplasmic regions were fused in a same exon. The primer extension technique was used to establish that the transcription initiation sites were located 92-95 bp upstream from the ATG start codon. DNA sequencing of the 5'-flanking region revealed the presence of a strong initiator element for TATA-less genes, two CAAT boxes, and numerous potential transcription factor binding sites including four E-box and two N-box sequences. Interspecific backcross analysis demonstrated that the Tlcn gene was mapped in the proximal region of mouse chromosome 9 in close vicinity to the Icam-1 gene, suggesting that Tlcn and Icam-1 are derived from a common ancestral gene by gene duplication.

Animals↗
PubMed1997

Human TNF receptor-associated factor 5 (TRAF5): cDNA cloning, expression and assignment of the TRAF5 gene to chromosome 1q32.

Tumor necrosis factor (TNF) receptor-associated factors (TRAFs) are signal transducers for members of the TNF receptor superfamily. We previously identified murine TRAF5 (mTRAF5) and showed that it specifically interacts with the lymphotoxin-beta receptor (LT-beta R) and activates the transcription factor NF-kappa B. Here we have cloned the human TRAF5 homologue (hTRAF5) by cross hybridization with mTRAF5 cDNA. hTRAF5 cDNA is composed of 2894 nucleotides with a 557-amino-acid open reading frame that exhibits 77.5 and 80% identity to mTRAF5 at the nucleotide and amino acid levels, respectively. Northern blot analysis revealed that hTRAF5 mRNA is expressed in all visceral organs. Western blotting revealed that hTRAF5 protein was abundantly expressed in the human follicular dentritic cell line, FDC-1, and to a much lesser degree in several tumor cell lines. Interspecific backcross mapping revealed that Traf5 is located in the distal region of mouse chromosome 1, which shares a region of homology with human chromosome 1q. Fluorescence in situ hybridization confirmed regional localization to human chromosome 1q32.

Amino Acid Sequence↗
PubMed1997

The laminin alpha chains: expression, developmental transitions, and chromosomal locations of alpha1-5, identification of heterotrimeric laminins 8-11, and cloning of a novel alpha3 isoform.

Laminin trimers composed of alpha, beta, and gamma chains are major components of basal laminae (BLs) throughout the body. To date, three alpha chains (alpha1-3) have been shown to assemble into at least seven heterotrimers (called laminins 1-7). Genes encoding two additional alpha chains (alpha4 and alpha5) have been cloned, but little is known about their expression, and their protein products have not been identified. Here we generated antisera to recombinant alpha4 and alpha5 and used them to identify authentic proteins in tissue extracts. Immunoprecipitation and immunoblotting showed that alpha4 and alpha5 assemble into four novel laminin heterotrimers (laminins 8-11: alpha4beta1gamma1, alpha4beta2gamma1, alpha5beta1gamma1, and alpha5beta2gamma1, respectively). Using a panel of nucleotide and antibody probes, we surveyed the expression of alpha1-5 in murine tissues. All five chains were expressed in both embryos and adults, but each was distributed in a distinct pattern at both RNA and protein levels. Overall, alpha4 and alpha5 exhibited the broadest patterns of expression, while expression of alpha1 was the most restricted. Immunohistochemical analysis of kidney, lung, and heart showed that the alpha chains were confined to extracellular matrix and, with few exceptions, to BLs. All developing and adult BLs examined contained at least one alpha chain, all alpha chains were present in multiple BLs, and some BLs contained two or three alpha chains. Detailed analysis of developing kidney revealed that some individual BLs, including those of the tubule and glomerulus, changed in laminin chain composition as they matured, expressing up to three different alpha chains and two different beta chains in an elaborate and dynamic progression. Interspecific backcross mapping of the five alpha chain genes revealed that they are distributed on four mouse chromosomes. Finally, we identified a novel full-length alpha3 isoform encoded by the Lama3 gene, which was previously believed to encode only truncated chains. Together, these results reveal remarkable diversity in BL composition and complexity in BL development.

Amino Acid Sequence↗
PubMed1997

Cloning and chromosomal localization of mouse aquaporin 4: exclusion of a candidate mutant phenotype, ataxia.

Aquaporin-4 is a mammalian water channel protein that is predominately expressed in brain, where it is believed to mediate water homeostasis. Here we report the isolation and characterization of the cDNA for mouse Aqp4 and map the gene to the proximal region of mouse chromosome 18. This region contains the neurological mutation ataxia, but further analysis reveals that Aqp4 is not responsible for the ataxia phenotype.

Amino Acid Sequence↗
PubMed1997

The Nab2 and Stat6 genes share a common transcription termination region.

The two Nab genes, coding for transcriptional corepressors of NGFI-A (Egr-1, Krox24, zif268) and Krox20, have been localized to two regions of the genome, each of which contains at least two members of the Stat gene family. The association of the two Nab genes with the Stat clusters on mouse chromosomes 1 and 10 (human chromosomes 2 and 12) suggest that a Nab gene was involved in at least one of the duplication events that resulted in dispersion of the primordial Stat gene pair to three different mouse chromosomes. Sequencing of the Nab2 genomic locus revealed that it is situated very close to the Stat6 gene. The transcripts of the two genes converge, such that the 3' ends of the Stat6 and Nab2 mRNAs overlap by 58 bp. Both transcripts terminate within a 78-bp region that is absolutely conserved between mouse and human. Analysis of Nab2 cDNA revealed that there is an alternatively spliced form of the Nab2 transcript (lacking exon 3) that produces a protein that lacks the ability to repress transcription by NGFI-A and Krox20.

Alternative Splicing↗
PubMed1997

A family of secreted proteins contains homology to the cysteine-rich ligand-binding domain of frizzled receptors.

This paper describes the identification of a new family of mammalian genes that encode secreted proteins containing homology to the cysteine-rich ligand-binding domain found in the frizzled family of transmembrane receptors. The secreted frizzled-related proteins (sFRPs) are approximately 30 kDa in size, and each contains a putative signal sequence, a frizzled-like cysteine-rich domain, and a conserved hydrophilic carboxy-terminal domain. The sFRPs are not the products of differential splicing of the known frizzled genes. Glycosylphosphatidylinositol-anchored derivatives of sFRP-2 and sFRP-3 produced in transfected human embryonic kidney cells confer cell-surface binding by the Drosophila Wingless protein. These observations suggest that sFRPs may function in vivo to modulate Wnt signaling, or, alternatively, as novel ligands for as yet unidentified receptors.

Amino Acid Sequence↗
PubMed1997

Identification and mapping of Casp7, a cysteine protease resembling CPP32 beta, interleukin-1 beta converting enzyme, and CED-3.

Cloning of interleukin-1 beta converting enzyme (ICE) and Caenorhabditis elegans death protein CED-3 revealed the structural and functional homology between these two proteases. It also suggested the involvement of ICE-like cysteine proteases in apoptosis. Several CED-3- and ICE-like cysteine proteases have been described, including Nedd2/Ich-1, CPP32 beta, Tx, ICErel3, and Mch2. We have previously described a mouse ortholog of cysteine protease CPP32 beta that shares strong homology with ICE and CED-3. Here, we describe the cloning of mouse and human Casp7, another member of this family of cysteine proteases. Mouse Casp7 encodes a putative 340-amino-acid polypeptide that contains all the known conserved residues required for protease function, including the QACRG sequence, aspartic acid residues for internal cleavage sites, and the residues required for substrate binding. Three RNA variants of human Casp7 were also cloned. Amino acid sequence analysis indicated that Casp7 shared high homology with CPP32 beta/Casp3 and Mch2/Casp6. Northern blot analysis demonstrated that a 2.6-kb Casp7 mRNA was expressed in various tissues except brain. Mouse interspecific backcross mapping allowed localization of Casp7 to the distal region of mouse chromosome 19, linked to Mxi1, Adra2a, and Aop1.

Amino Acid Sequence↗
PubMed1997

DUB-2 is a member of a novel family of cytokine-inducible deubiquitinating enzymes.

Cytokines regulate cell growth by inducing the expression of specific target genes. We have recently identified a cytokine-inducible, immediate-early gene, DUB-1, that encodes a deubiquitinating enzyme with growth regulatory activity. In the current study, we have isolated a highly related gene, DUB-2, that is induced by interleukin-2. The DUB-2 mRNA was induced in T cells as an immediate-early gene and was rapidly down-regulated. Like DUB-1, the DUB-2 protein had deubiquitinating activity in vitro. When a conserved cysteine residue of DUB-2, required for ubiquitin-specific thiol protease activity, was mutated to serine (C60S), deubiquitinating activity was abolished. DUB-1 and DUB-2 proteins are highly related throughout their primary amino acid sequence except for a hypervariable region at their COOH terminus. Moreover, the DUB genes co-localize to a region of mouse chromosome 7, suggesting that they arose by a tandem duplication of an ancestral DUB gene. Additional DUB genes co-localize to this region, suggesting a larger family of cytokine-inducible DUB enzymes. We propose that different cytokines induce specific DUB genes. Each induced DUB enzyme thereby regulates the degradation or the ubiquitination state of an unknown growth regulatory factor, resulting in a cytokine-specific growth response.

Animals↗
PubMed1997

Mouse CD-RAP/MIA gene: structure, chromosomal localization, and expression in cartilage and chondrosarcoma.

A cDNA encoding a novel protein has been previously isolated from two independent sources: melanoma cell cultures and chondrocytes. The protein from human melanoma cell lines and tumors is called melanoma inhibitory activity (MIA) (Blesch et al. [1994] Cancer Res. 54:5695-5701) and the protein from primary bovine chondrocytes and cartilaginous tissues is called cartilage-derived retinoic acid-sensitive protein (CD-RAP) (Dietz and Sandell [1996] J. Biol. Chem. 271:3311-3316). In order to investigate the gene regulation and function of CD-RAP/MIA, the mouse gene locus was isolated and analyzed. Developmental expression was determined by in situ hybridization to mouse embryos. Expression was limited to cartilaginous tissues and was initiated with the advent of chondrogenesis, remaining abundant throughout development. The mouse gene was isolated and sequenced from a 129Sv library and sequenced directly from an additional strain, B6C3Fe. The mouse CD-RAP/MIA gene is 1.5 kbp and consists of four exons. The promoter sequence of the gene contains many potential regulatory domains including 8 basic helix-loop-helix protein-binding domains and an AT-rich domain, both motifs shown to be present in the cartilage-specific enhancer of the type II procollagen gene. Other potential cis-acting motifs include binding sites for GATA-1, NF-IL6, PEA3, w-elements, NF kappa B, Zeste and Sp1. The gene, called cdrap, was localized to the end of an arm of chromosome 7 at the same site as the transforming growth factor beta 1 (Tgf-beta 1) and the glucose phosphate isomerase 1 (Gpi 1) genes. Potential mouse mutants that mapped to the same region of chromosome 7 were identified. Two of the potential mutants with skeletal phenotypes were sequenced, pudgy (pu) and extra toes with spotting (XsJ); however, no mutations were found in the coding sequence. To determine whether CD-RAP/MIA is associated with tumors of cartilage, mRNAs from a variety of rodent tissues and cell lines were screened. Expression was detected in a rodent tumor, the Swarm rat chondrosarcoma and a chondrosarcoma cell line derived from it, but not in other tissues or tumors of non-cartilage origin. Immunolocalization revealed CD-RAP/MIA protein localized in cartilage only. These results show that the normal expression of CD-RAP/MIA is limited to cartilage; however, pathologically, it is expressed both in melanoma and chondrosarcoma. The restricted expression of CD-RAP/MIA may provide an opportunity to monitor cartilage metabolic activity as well as the tumor activity of melanoma and chondrosarcoma.

Amino Acid Sequence↗
PubMed1997

Matrix metalloproteinase-9 maps to the distal end of chromosome 2 in the mouse.

The activity and expression of matrix metalloproteinase-9/gelatinase B (MMP-9), an enzyme implicated in the implantation process in mice, was investigated in normal and parthenogenetic blastocyst outgrowths. Conditioned media from parthenogenetic blastocysts after 4 days of culture had reduced levels of MMP-9 activity compared to conditioned medium from normal outgrowths. Levels of MMP-9 mRNA assayed by reverse transcription-polymerase chain reaction methods were also reduced in parthenogenetic blastocysts compared to normal outgrowths. Genetic mapping studies showed that Mmp9 maps to the distal end of chromosome 2 near the proximal boundary of a region affected by genomic imprinting. Both parental alleles of Mmp9, however, are expressed in 11.5-day embryos derived from interspecific crosses of Mus musculus and Mus spretus. Thus, loss of MMP-9 activity in parthenogenetic blastocysts does not appear to be due to imprinting but, rather, due to a defect of trophoblast giant cell proliferation and differentiation.

Animals↗
PubMed1997

The mouse Spam1 maps to proximal chromosome 6 and is a candidate for the sperm dysfunction in Rb(6.16)24Lub and Rb(6.15)1Ald heterozygotes.

We have determined the chromosomal localization of the murine gene encoding the 68-kDa sperm adhesion molecule 1, Spam1 or Ph-20. Using two independent approaches, fluorescence in situ hybridization (FISH) and interspecific backcross analysis we show the Spam1 maps to proximal mouse Chromosome (Chr) 6. This map position is within the conserved linkage group corresponding to human Chr 7q, where the human homolog, SPAM 1, has been shown to map previously. Genetic mapping shows the gene to be very closely linked to Met, one of the most proximal loci on MMU 6. It thus places the gene near the centromere and the junction of the Rb(6.16)24Lub and Rb(6.15)1Ald translocations. The essential role of the Spam1 sperm antigen in mouse sperm-egg interactions and its gene location provide strong support for its candidacy as the gene involved in the dysfunction of mouse sperm bearing the Rb(6.16)24Lub or Rb(6.15)1Ald translocation.

Animals↗
PubMed1997

Eyes absent: a gene family found in several metazoan phyla.

Genes related to the Drosophila eyes absent gene were identified in vertebrates (mouse and human), mollusks (squid), and nematodes (C. elegans). Proteins encoded by these genes consist of conserved C-terminal and variable N-terminal domains. In the conserved 271-amino acid C-terminal region, Drosophila and vertebrate proteins are 65-67% identical. A vertebrate homolog of eyes absent, designated Eya2, was mapped to Chromosome (Chr) 2 in the mouse and to Chr 20q13.1 in human. Eya2 shows a dynamic pattern of expression during development. In the mouse, expression of Eya2 was first detected in 8.5-day embryos in the region of head ectoderm fated to become the forebrain. At later stages of development, Eya2 is expressed in the olfactory placode and in a variety of neural crest derivatives. In the eye, expression of Eya2 was first detected after formation of the lens vesicle. At day 17.5, the highest level of Eya2 mRNA was observed in primary lens fibers. Low levels of Eya2 expression was detected in retina, sclera, and cornea. By postnatal day 10, Eya2 was expressed in secondary lens fibers, cornea, and retina. Although Eya2 is expressed relatively late in eye development, it belongs to the growing list of factors that may be essential for eye development across metazoan phyla. Like members of the Pax-6 gene family, eyes absent gene family members were probably first involved in functions not related to vision, with recruitment for visual system formation and function occurring later.

Age Factors↗