Biomedical subjects

K Mesa

Publications and source records attributed to K Mesa.

5 recordsLinked to original sources

PubMed1998

Molecular cloning and characterization of TIEG2 reveals a new subfamily of transforming growth factor-beta-inducible Sp1-like zinc finger-encoding genes involved in the regulation of cell growth.

Sp1-like zinc finger transcription factors are involved in the regulation of cell growth and differentiation. Recent evidence demonstrating that mammalian cells express novel, yet uncharacterized, Sp1-like proteins has stimulated a search for new members of this family. We and others have recently reported that the transforming growth factor (TGF)-beta-regulated gene TIEG encodes a new Sp1-like protein that inhibits cell growth in cultured cells. Here we report the identification, nuclear localization, DNA binding activity, transcriptional repression activity, and growth inhibitory effects of TIEG2, a novel TGF-beta-inducible gene related to TIEG. TIEG2 is ubiquitously expressed in human tissues, with an enrichment in pancreas and muscle. TIEG2 shares 91% homology with TIEG1 within the zinc finger region and 44% homology within the N terminus. Biochemical characterization reveals that TIEG2 is a nuclear protein, which, as predicted from the primary structure, specifically binds to an Sp1-like DNA sequence in vitro and can repress a promoter containing Sp1-like binding sites in transfected Chinese hamster ovary epithelial cells. Furthermore, functional studies using [3H]thymidine uptake and MTS (3-(4, 3-dimethyltiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-su lfophenyl)-2 H-tetrazolium) assays demonstrate that the overexpression of TIEG2 in Chinese hamster ovary cells inhibits cell proliferation. Thus, TIEG2, together with TIEG1, defines a new subfamily of TGF-beta-inducible Sp1-like proteins involved in the regulation of cell growth.

Amino Acid Sequence↗

PubMed1997

Tooth avulsions resulting from basketball net entanglement.

The authors conducted a survey of dentists reporting tooth avulsions from basketball net accidents. Although the number of people injured was small, the dental injuries were serious. In many cases, multiple teeth were avulsed as a result of the maxillary anterior teeth becoming entangled in the basketball net while the patients were attempting to slamdunk a basketball either on a lowered backboard or from a raised take-off area. The authors present recommendations for preventing tooth avulsions resulting from basketball net entanglement.

Accidents, Home↗

PubMed1996

A novel profile of expressed sequence tags for zinc finger encoding genes from the poorly differentiated exocrine pancreatic cell line AR4IP.

Genes encoding for C2H2 zinc finger proteins are known to regulate normal cell proliferation and differentiation and have often been found to be mutated in different forms of cancer. We are interested in understanding the role of these genes as regulators of cell proliferation and differentiation in the exocrine pancreas. Therefore, we have generated expressed sequence tags (ESTs) encoding pancreas-enriched zinc finger peptides using the polymerase chain reaction and hybridization techniques [Adams, M.D. et al. (1991) Science, 252, 1651-1656]. Here we report the primary structure and expression pattern of 18 different zinc finger-encoding cDNAs (DZF-1-18) from the azaserine-derived tumoral cell line AR4IP which displays a poorly differentiated phenotype. Sequence analysis shows that all of these clones encode peptides which share the consensus DNA-binding motif with the Drosophila zinc finger transcription factor krüppel. High stringency Northern blot analysis shows that eight different zinc finger transcripts are expressed at high levels in normal adult rat pancreas and therefore constitute good candidates to play a role as transcription factors in exocrine pancreatic cells.

Animals↗

PubMed1996

Identification and characterization of zinc finger encoding genes from the tumoral exocrine pancreatic cell line AR42J.

Zinc finger transcription factors are DNA-binding proteins that are known to determine the identity of cells by regulating cell-specific gene expression. In addition, mutations in some members of this family have been found to be associated with several neoplasias, including Wilms' tumor and leukemias. Because the mechanisms that regulate normal, as well as neoplastic, pancreatic cell differentiation are poorly understood, we are searching for pancreas-enriched transcription factors that may determine the identity of pancreatic cells. Towards this end, we have used the polymerase chain reaction and degenerate primers against the highly conserved (Cys2-His2) zinc finger domain to amplify novel transcription factor encoding cDNAs from the well-characterized pancreatic acinar cell line AR42J. Using this approach, we have identified 17 different zinc finger encoding cDNAs (AZF-1 to -17). Sequence analysis shows that all of these clones encode for different zinc finger peptides which share the consensus DNA binding motif with the Drosophila transcription factor krüppel. As a first step in the characterization of these genes, the purified PCR products were used to determine their spatial pattern of expression by northern blot analysis. Using these techniques, we find that numerous zinc finger encoding genes are expressed in AR42J acinar cells as well as in normal adult rat pancreas and suggest that they may play a role as transcription factors in exocrine pancreatic cells.

Age Factors↗

PubMed1996

Three dynamin-encoding genes are differentially expressed in developing rat brain.

Dynamin proteins are members of a recently described family of GTPases involved in receptor-mediated processes. To date, three different dynamin-encoding genes have been identified in mammalian tissues. Dynamin I is expressed only in neurons, whereas dynamin II is ubiquitously expressed. A third isoform, dynamin III, was originally isolated from a rat testis cDNA library and shown to be testis-specific. However, here we report the cloning and characterization of dynamin III from brain and lung, demonstrating a more extended pattern of expression for this isoform. In addition, we have investigated the temporal pattern of expression of these three genes during brain development. We find that both dynamin I and dynamin III mRNA levels are up-regulated during embryogenesis, whereas dynamin II mRNA levels remain unchanged. From these results, we conclude that dynamin III is not a testis-specific isoform and, furthermore, that rat brain expresses three different dynamin-encoding genes that are differentially regulated during development. Therefore, this large isoform diversity of dynamin proteins in brain predicts a significant complexity in the understanding of dynamin-based processes in this tissue.

Alternative Splicing↗