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Biomedical subjects

T B Shows

Publications and source records attributed to T B Shows.

At least 91 records · Page 5Linked to original sources
PubMed1993

Chromosome mapping and organization of the human beta-galactoside alpha 2,6-sialyltransferase gene. Differential and cell-type specific usage of upstream exon sequences in B-lymphoblastoid cells.

The human beta-galactoside alpha 2,6-sialyltransferase (EC 2.4.99.1) (SiaT-1) gene is localized to human chromosome 3 (q21-q28) by Southern analysis of somatic cell hybrids and by in situ hybridization of metaphase chromosomes. Comparative analysis between the human and the previously reported rat SiaT-1 genomic sequences demonstrates precise conservation of the intron/exon boundaries throughout the coding domains. Furthermore, there is extensive inter-species sequence similarity in some of the exons that contain information only for the 5'-leader regions. Human genomic sequences were also analyzed to reconcile reported differences in the 5'-untranslated region in SiaT-1 mRNAs. In cultured cell lines of the B-lineage, Reh, Nalm-6, Jok-1, Ball-1, Daudi, and Louckes, the study demonstrates that three upstream exons, Exons(Y+Z) and Exon(X), are mutually exclusively utilized, resulting in at least two distinct populations of SiaT-1 mRNA being synthesized. None of these exons is present in the SiaT-1 mRNA isotype expressed in HepG2 human hepatoma cells. In all B-lymphoblastoid cell lines examined, the basal level SiaT-1 mRNA is maintained by the expression of an isotype containing the Exons(Y+Z) sequence. The slightly smaller SiaT-1 mRNA, which contains the Exon(X) sequence but not Exons(Y+Z) sequence, is synthesized at a high level and found only in Jok-1, Daudi, and Louckes, the cell lines with mature B-cell phenotype. The study also provides further evidence that induced SiaT-1 expression accompanies the appearance of CDw75, a putatively sialylated cell surface epitope and a marker of human mature B-lymphocytes. The SiaT-1 induction is the result of the appearance of a novel form of SiaT-1 mRNA isotype.

Animals↗
PubMed1993

Human chemotaxis receptor genes cluster at 19q13.3-13.4. Characterization of the human C5a receptor gene.

The human C5a anaphylatoxin and formyl peptide receptor genes, as well as two genes with high sequence identity to the formyl peptide receptor, FPRH1 and FPRH2, have been mapped to chromosome 19 (Lu et al., 1992). Further analysis reveals that these genes are present in the 19q13.3 band adjacent to the 13.3-13.4 interface. MRNAs for the C5a and formyl peptide receptors, as well as for FPRH1, are expressed in cAMP differentiated U937 cells and human eosinophils, while all four transcripts are expressed in human lung. This observation opens the possibility for coordinate regulation of these genes. In order to initiate the mapping of fine structure at this locus, genomic clones have been analyzed. All four of the genes have a similar structure, with the receptor protein encoded in a single exon. Detailed characterization of the C5a receptor gene reveals a two exon structure, with the 5' untranslated sequence and initiating methionine located in the first exon. An intron of approximately 9 kb separates exon 1 from the receptor-encoding exon 2. The region of genomic DNA flanking the 5' untranslated sequence possesses promoter activity when transfected into the myeloid-derived rat basophilic leukemia RBL-1 cells, but the same region is inactive when transfected into nonmyeloid cells. Deletional analyses indicate that C5a receptor 5' flanking region contains both cell-specific suppressor and promoter regions.

Animals↗
PubMed1993

A t(11;12) 11q23 leukemic breakpoint that disrupts the MLL gene.

Translocations involving 11q23 have been shown to be a consistent finding in human hematopoietic malignancies and in some constitutional abnormalities. The identification of a gene, MLL (myeloid/lymphoid or mixed-lineage leukemia), that spans the breakpoints in four different recurrent 11q23 translocations was recently reported. We describe a rare (11;12)(q23;p13) translocation, observed in leukemic cells from a patient with acute lymphoblastic leukemia, which also disrupts this gene.

Blotting, Southern↗
PubMed1993

Molecular analysis of a t(11;14)(q23;q11) from a patient with null-cell acute lymphoblastic leukemia.

/lp;&-3qChromosome 11, band q23, is the frequent site of recurring cytogenetic rearrangements in human leukemia. We have cloned and sequenced the breakpoint junctions from a patient who had null-cell acute lymphoblastic leukemia (ALL) with a t(11;14)(q23;q11). The chromosome 14 breakpoints occurred within the TCRD locus, close to two diversity segments. The chromosome 11 breakpoint occurred between two head-to-head heptamer sequences, and junctional diversity was evident at both derivative junctions, suggesting involvement of the V(D)J recombinase. The TCRA/D locus on the normal chromosome 14 had undergone a V delta 2-D delta 3-psi J alpha joining. Two phage clones with this VDJ rearrangement were isolated; one of these contained an intra-J alpha region deletion. Two clones with the derivative 11 junction were isolated; one of these had a similar, but not identical, deletion. A heptamer-nonamer recognition sequence (located approximately 70 kb 5' to C alpha), not associated with a TCR gene coding segment, was found in the immediate vicinity of both 5' breakpoints. We have designated this sequence 5'del for 5' deleting element. An intra-J alpha region deletion involving this heptamer-nonamer was previously identified in the leukemia cells recovered from a patient who had T-cell ALL. Fifty kilobases of DNA on 11q23 surrounding the breakpoint were cloned and analyzed. No CpG islands or conserved sequences were identified within this region.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Characterization of two 11q23.3-11q24 deletions and mapping of associated anonymous DNA markers.

Translocations in bands 11q23.3-11q24 are associated with several human cancers, including acute lymphoid and acute myeloid leukemias (AML) and Ewing's sarcoma. We have characterized two independent deletions in this region, one derived from a patient with AML who previously had a T-cell lymphoma, and another from a Wilms' tumor patient. Cytogenetic analysis of the ML-2 cell line established from the malignant cells of the AML patient indicated that one chromosome 11 homolog had an interstitial deletion, del(11) (q23q24), and the remaining homolog was involved in a recurring translocation, t(6;11) (q27;q23). According to karyotype analysis on the Wilms' tumor patient (EH), one chromosome 11 was normal and the other carried an interstitial deletion at 11q23.3-11q25. Somatic cell hybrids segregating the EH deletion (EHR4) and the ML-2 deletion (MLR4) have been isolated. The EH deletion is distal to the MLL probe recently associated with 11q23.3 leukemia breakpoints (Ziemin-van der Poel et al.: Proc Natl Acad Sci USA 88:10735-10739, 1991). The ML-2 deletion could involve the MLL gene at a point distal to other breakpoints within MLL. Both deletions include the Ewing's sarcoma breakpoint at 11q24.1. By Southern blot analysis we identified three anonymous DNA markers (D11S272, D11S273, and D11S219) and the ETS/oncogene, which map within each deleted region. These markers are conserved based on zoo blot analysis, and they are valuable for physical mapping and genetic characterization of a region that may code for gene products associated with growth control and tumor suppression in a variety of cancers.

Animals↗
PubMed1993

The genes for the lipopolysaccharide binding protein (LBP) and the bactericidal permeability increasing protein (BPI) are encoded in the same region of human chromosome 20.

The lipopolysaccharide binding protein is an acute-phase reactant produced during gram-negative bacterial infections. The bactericidal/permeability increasing protein is associated with human neutrophil granules and has bactericidal activity on gram-negative organisms. In addition to their functional relationship, both proteins share extensive structural similarity. This article demonstrates that the genes for both proteins are in the same region of human chromosome 20, between q11.23 and q12.

Acute-Phase Proteins↗
PubMed1993

A human chromosome 11 NotI end clone library.

A NotI end clone library has been constructed from a human-hamster hybrid cell line containing only human chromosome 11. Fifty-one NotI clones were chosen to characterize the library. The majority of NotI clones hybridize to small 15- to 200-kb fragments and have proven to be valuable for chromosome 11 physical mapping by detecting fragments not previously recognized by random probes. These NotI end clones have been used to isolate corresponding NotI linking cosmids which were then used to identify adjacent NotI fragments on pulsed-field gels. The clones were mapped using fluorescence in situ hybridization and a somatic cell hybrid panel. Although these clones were localized over the entirety of chromosome 11, a nonrandom distribution was observed. Northern blot analysis indicated that 57% (17/30) of the NotI clones examined detected poly(A)+ transcripts in HeLa cell RNA.

Animals↗
PubMed1993

A chromosome 11 YAC library.

A targeted yeast artificial chromosome (YAC) library for chromosome 11 has been constructed from the J1 cell line that carries a single human chromosome 11 within a hamster DNA background. Interspecies chimeric clones generated during construction of the library were detected during the screening process and eliminated from the library. Contig assembly becomes much less difficult using such a library as the complexity is decreased and the ends of the clone inserts can be rescued for walking to neighboring clones. The library contains > 1824 clones with an average insert length of 337 kb. This represents a fourfold coverage of chromosome 11 or a > 95% chance of recovering a unique single-copy sequence from the library. Two hundred YAC clones were localized by fluorescence in situ hybridization and found to be randomly distributed along the chromosome. The library has been screened with probes for the chromosome 11 markers HBB, GLUR4, H19, and D11S193. Corresponding YAC clones have been isolated for each locus. This analysis has indicated that the library is unbiased, that cognate YAC clones can be recovered with chromosome 11 markers, and that extensive contig assembly should be feasible.

Animals↗
PubMed1993

Cloning of a portion of the chromosomal gene and cDNA for human beta-fodrin, the nonerythroid form of beta-spectrin.

A 96-bp synthetic oligonucleotide corresponding to an amino acid sequence near the N-terminus of erythroid beta-spectrin was used to screen a human genomic library, and two overlapping recombinants were isolated. DNA sequence analysis established that the genomic fragment encoded beta-fodrin, the nonerythroid form of beta-spectrin, by correlation to a known amino acid sequence of human brain beta-fodrin. The genomic DNA contained regions that cross-hybridized with an erythroid beta-spectrin cDNA probe, and the DNA sequence of these regions revealed a high degree of identity with that of erythroid beta-spectrin and a similar exon/intron organization. A single-copy DNA fragment of the beta-fodrin genomic clone was used to screen a lymphoid cell cDNA library and two recombinants were isolated. The composite DNA sequence of these various genomic and cDNA clones encoded almost all of the first twelve 106 amino acid repeat segments of beta-fodrin that shared 58% identity and 75.5% similarity with the amino acid sequence of beta-spectrin and 66% identity with the nucleotide sequence of beta-spectrin cDNA. The chromosomal localization of the gene was determined to be chromosome 2 by hybridization of a single-copy probe derived from the cloned genomic DNA to DNA of a panel of somatic hybrid cell lines, and in situ hybridization localized the gene to band 2p21. beta-Fodrin was assigned the gene symbol SPTBN1.

Amino Acid Sequence↗
PubMed1993

Correction of mucolipidosis III in vitro by gene transfer.

Mucolipidosis II (ML II, I-cell disease) and mucolipidosis III (ML III, pseudo-Hurler polydystrophy) are human autosomal recessive genetic disorders resulting from deficient UDP-N-acetylglucosamine:lysosomal enzyme precursor N-acetylglucosamine-1-phosphotransferase (GNPT) activity. Normally, this enzyme is involved in the processing of most lysosomal enzymes. Cultured fibroblasts from individuals with either disorder are deficient in a broad array of lysosomal enzymes as a result of the diminished GNPT activity. We report the correction of this phenotype by fusing transformed ML III cells generated for this study to lethally irradiated rodent cells. This method of gene transfer does not require selection for the gene of interest, animal models, nor any knowledge of the gene product except a screening method for its presence. It has generated corrected cell hybrids that contain approximately 1% hamster-derived sequences. These cell lines, which contain the hamster analogue to the human phosphotransferase gene, are useful for the molecular cloning of the gene defective in ML II and ML III.

Animals↗
PubMed1993

Linkage of Agt and Actsk-1 to distal mouse chromosome 8 loci: a new conserved linkage.

Angiotensinogen is an alpha 2-globulin involved in the maintenance of blood pressure and electrolyte balance. We have refined the position of the mouse angiotensinogen locus (Agt) on Chromosome (Chr) 8 and have also confirmed the assignment of the human angiotensinogen locus (AGT) to Chr 1. The segregation of several restriction fragment length variants (RFLVs) was followed in two interspecific backcross sets and in four recombinant inbred (RI) mouse sets. Analysis of the segregation patterns closely linked Agt to Aprt and Emv-2, which places the angiotensinogen locus on the distal end of mouse Chr 8. Additionally, a literature search has revealed that the strain distribution pattern (SDP) for the mouse skeletal alpha-actin locus 1 (Actsk-1, previously Acta1, Acta, or Acts) is nearly identical to the SDP for Agt in two RI sets. On the basis of this information we were able to reassign Actsk-1 to mouse Chr 8. By screening a panel of human-mouse somatic cell hybrids, we confirmed that the human angiotensinogen locus lies on Chr 1. This information describes a new region of conserved linkage homology between mouse Chr 8 and human Chr 1. It also defines the end of a large region of conserved linkage homology between mouse Chr 8 and human Chr 16.

Actins↗
PubMed1993

Mapping of the genes for human endoplasmic reticular heat shock protein gp96/grp94.

The murine tumor rejection antigen gp96 (TRA1, mapped to mouse chromosome 10) is a member of the heat shock protein family. Using a fragment of the murine gp96 cDNA as a probe, three gp96-related human genes have been isolated and structurally characterized. They have been mapped to human chromosomes 1 (p22), 12 (q24.2-->q24.3), and 15 (q25-->q26) by Southern blot hybridization and in situ hybridization of gene-specific probes. Only one of the genes, designated TRA1 (human chromosome 12) is a coding gene; the other genes (TRA1P1 and TRAP2) appear to be independently derived, processed pseudogenes.

Animals↗
PubMed1993

Brn-3b: a POU domain gene expressed in a subset of retinal ganglion cells.

A search for POU domain transcription factors in human retina cDNA has led to the identification of Brn-3b, a class IV POU domain protein. Immunohistochemical experiments show that chicken, mouse, rabbit, monkey, and human retinas contain Brn-3b exclusively within a subpopulation of ganglion cells. In the adult mouse brain, Brn-3b is found only within cells in the deep layers of the superior colliculus, in the dorsal periaqueductal gray, and in a small cluster of cells in the brain stem near the area postrema. During the immediate postnatal period, cells containing Brn-3b are distributed in a number of regions within the brain stem and cerebellum. These data suggest that Brn-3b plays a role in determining and/or maintaining the identities of a small number of neurons, including a subset of visual system neurons.

Amino Acid Sequence↗
PubMed1993

Molecular genetics of Alport syndrome.

Alport syndrome is a progressive hereditary kidney disease characterized by hematuria, sensorineural hearing loss and ocular lesions with structural defects in the glomerular basement membrane (GBM). The gene frequency has been estimated to be 1:5000. The disease is primarily X chromosome-linked, but autosomal forms have also been reported. The X-linked form has been shown to be caused by mutations in a recently identified alpha 5(IV) collagen chain gene (COL4A5). We have isolated cDNA clones for providing the entire primary structure of the human alpha 5(IV) chain. The gene has been located to the Xq22 region. Using antibodies against synthetic peptides, the alpha 5(IV) chain was shown to be located in the kidney only in the glomerular basement membrane. Thus far, the exon-intron structure has been determined for a large portion of the gene which probably has a size of over 200 kb. Numerous different mutations have been identified in the COL4A5 gene. The mutations include single base mutations, large deletions and other major rearrangements such as inversion and duplication. The consequences of the mutations observed can be considered sufficient to cause structural and functional defects in the type IV collagen molecule and, therefore, also the GBM network. This, in turn can explain the disruption of the GBM and hematuria occurring in these Alport patients. Alport syndrome is the first genetic basement membrane and kidney disease whose gene has been cloned. These recent results have enabled the development of antibodies and DNA probes for accurate diagnosis of Alport syndrome.

Chromosome Mapping↗
PubMed1993

Localization of the human collagen gene COL7A1 to 3p21.3 by fluorescence in situ hybridization.

An 8-kb genomic probe, containing 34 collagen-encoding exons, was localized to 3p21.3 by fluorescence in situ hybridization. The genomic probe encoded a previously uncharacterized carboxyl terminal portion of the alpha 1(VII) collagen chain. This mapping result confirms the previous assignment of the alpha 1(VII) gene (COL7A1) to 3p21 and offers a finer subregional localization than was previously available.

Animals↗
PubMed1993

Chromosomal localization and nucleoside diphosphate kinase activity of human metastasis-suppressor genes NM23-1 and NM23-2.

Human metastasis-suppressor genes nm23-1 (NME1) and nm23-2 (NME2) are implicated in control of the metastatic potential of malignant cells. Using somatic cell hybrid analysis and fluorescence in situ hybridization we co-localized both genes to 17q21.3. The 17q21 region carries the locus responsible for early-onset familial breast-ovarian cancer and several other genes that are involved in tumorigenesis and differentiation and undergo frequent rearrangements during neoplastic development. Thus, our mapping places the NME genes in a region that may be subjected to multiple selection pressures. NME1 and NME2 genes were expressed as soluble proteins in a T7 bacterial expression system. Both proteins are independently active nucleotide diphosphate kinases and readily form intra- and intermolecular disulfide bonds. The biochemical properties of these proteins may explain the diversity of mature eucaryotic nucleoside diphosphate kinases.

Animals↗
PubMed1992

Cloning of a novel tumor necrosis factor-alpha-inducible primary response gene that is differentially expressed in development and capillary tube-like formation in vitro.

TNF is a proinflammatory cytokine that has pleiotropic effects on cells and tissues, mediated in large part by alterations in target tissue gene expression. We have used the technique of differential hybridization to identify several primary response genes induced by TNF in human umbilical vein endothelial (HUVE) cells, a cell type that is profoundly activated by cytokine treatment. One of these cDNA, designated B94, detects a rapidly and transiently induced 4-kb transcript in TNF-treated HUVE cells, and this transcript is superinduced in the concomitant presence of cycloheximide. Other proinflammatory stimuli including IL-1 beta and LPS are also able to induce B94 mRNA expression. Nuclear run-on experiments demonstrate that TNF induction of B94 transcript occurs primarily at the level of transcriptional activation. Further, B94 is shown to be a single copy gene that is evolutionarily conserved. The gene is localized to the q32 region of chromosome 14, a region that is often rearranged in lymphoid neoplasms. B94 transcript expression is also found to be regulated during mouse development and in an in vitro model of endothelial capillary tube formation. Developmental regulation occurs most prominently in mouse embryonic liver and kidney, and a second smaller form of B94 transcript is detected in the placenta and testes. B94 and other TNF-responsive transcripts are also induced during capillary tube formation suggesting overlap between genes induced by TNF and those induced during angiogenesis. Sequence analysis of the B94 cDNA reveals an open reading frame encoding a 73-kDa polypeptide that has no homology to any known protein. Polyclonal antisera directed against the carboxyl-terminal portion of the B94 protein immunoprecipitates a protein of the predicted molecular mass both from COS cells transfected with a B94 expression vector and from TNF-treated HUVE cells.

Amino Acid Sequence↗