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R Utrera

Publications and source records attributed to R Utrera.

6 recordsLinked to original sources
PubMed2000

Cloning, chromosome mapping and functional characterization of a human homologue of murine gtse-1 (B99) gene.

Murine Gtse-1 (G(2) and S phase expressed protein), previously named B99, is a wt-p53 inducible gene that encodes a microtubule-localized protein which is able to induce G(2)/M phase accumulation when ectopically expressed. Here we report the cloning and characterization of a new cDNA (GTSE-1) encoding a human homologue of the mouse Gtse-1 protein. Chromosome mapping of mouse and human genes assigned Gtse-1 to chromosome 15 and GTSE-1 to chromosome 22q13.2-q13.3 in a region with conserved synteny to that where Gtse-1 mapped. Analysis of the genomic structure revealed that GTSE-1 contains at least 11 exons and 10 introns, spanning approximately 33kb of genomic DNA. Similar to murine Gtse-1, the product of GTSE-1 localized to the microtubules, was able to delay G(2)/M progression when ectopically expressed and was cell cycle regulated. Taken together, these results indicate GTSE-1 as the human functional homologue of murine Gtse-1.

Amino Acid Sequence↗
PubMed2000

GJB2 gene mutations in childhood deafness.

The frequency of childhood deafness is estimated at 1:1,000 and at least half of these cases are genetic. Recently, mutations in the GJB2 gene have been found in a great number of familial and sporadic cases of congenital deafness in Caucasians. The most common mutation (70%) is the frameshift mutation of a single guanine in position 35 (35delG). More than 20 mutations in the GJB2 gene are associated with DFNB1, a prevalent type of autosomal recessive non-syndromic neurosensory deafness. Last year we initiated a systematic screening programme to evaluate the causes of deafness in the population of prelingually deaf children who are referred to our cochlear implant programme. All of the deaf children and their parents undergo a comprehensive medical review, directed to identify causes of acquired deafness and manifestations of syndromic hearing impairment. DNA is extracted from the blood of all of the children. The technique AS-PCR (allele-specific polymerase chain reaction) is used for the identification of the mutation 35delG. Screening for other GJB2 gene mutations is carried out by single-strand conformation polymorphisms (SSCP). Our results on the identification of DFNB1 will be presented, as well as a discussion on the implications of an aetiological diagnosis in cochlear implantation.

Child↗
PubMed1999

wt p53 dependent expression of a membrane-associated isoform of adenylate kinase.

Six novel p53-inducible transcripts were recently cloned from Val5, a murine cell line stably expressing a temperature-sensitive p53 allele. One of the isolated clones represented a novel isoform of cytosolic adenylate kinase (AK1), a highly conserved monomeric enzyme involved in cellular homeostasis of adenine nucleotides. The corresponding protein, which we named AK1beta, was specifically induced upon activation of wt p53 in Val5 cells. The AK1beta protein differs from cytoplasmic AK1 by having 18 extra amino acids at the N-terminus. The extra residues in AK1beta provide a consensus signal for N-terminal myristoylation; as expected, AK1beta was shown to localize to the plasma membrane. The human AK1 gene contains several consensus p53 binding sites and we report that p53-dependent induction of the alternative AK1beta transcript also occurs in human cells. By using antisense ablation experiments in Val5 fibroblasts we show that AK1beta plays a relevant role in the establishment of reversible cell-cycle arrest as induced by p53 in these cells. These findings suggest that within a p53-dependent genetic program, a specific isoform of adenylate kinase has a previously undescribed growth-regulatory function, which might not necessarily require its best characterized biochemical activity.

3' Untranslated Regions↗
PubMed1998

A novel p53-inducible gene coding for a microtubule-localized protein with G2-phase-specific expression.

Wild-type (wt) p53 can act as a sequence-specific transcriptional activator and it is believed that p53 elicits at least part of its biological effects by regulating the expression of specific target genes. By using a differential subtractive hybridization approach in a murine cell line stably transfected with a temperature-sensitive p53 mutant (Val135), we isolated a set of genes markedly induced by wt p53. One of them, provisionally named B99, was further characterized; its transcriptional induction was dependent on wt p53 function and the corresponding protein product was shown to accumulate after DNA damage in different cell types. Immunofluorescence analysis located the B99 protein to the microtubule network. Flow cytometry revealed that upon activation of p53 function the endogenous B99 protein was selectively induced in the G2 fraction of the cell population. When B99 was ectopically expressed in p53-null murine fibroblasts, B99-transfected cells displayed an increased fraction with a 4N DNA content, indicative of interference with G2 phase progression. Taken together these data suggest that B99 might play a role in mediating specific biological activities of wt p53 during the G2 phase.

Amino Acid Sequence↗
PubMed1995

Gas1-induced growth suppression requires a transactivation-independent p53 function.

In normal cells, induction of quiescence is accompanied by the increased expression of growth arrest-specific genes (gas). One of them, gas1, is regulated at the transcriptional level and codes for a membrane-associated protein (Gas1) which is down regulated during the G0-to-S phase transition in serum-stimulated cells. Gas1 is not expressed in growing or transformed cells, and when overexpressed in normal fibroblasts, it blocks the G0-to-S phase transition. Moreover, Gas1 blocks cell proliferation in several transformed cells with the exception of simian virus 40- or adenovirus-transformed cell lines. In this paper, we demonstrate that overexpression of Gas1 blocks cell proliferation in a p53-dependent manner and that the N-terminal domain-dependent transactivating function of p53 is dispensable for Gas1-induced growth arrest. These data therefore indicate that the other intrinsic transactivation-independent functions of p53, possibly related to regulation of apoptosis, should be involved in mediating Gas1-induced growth arrest.

3T3 Cells↗