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Biomedical subjects

C Ponzetto

Publications and source records attributed to C Ponzetto.

At least 55 records · Page 3Linked to original sources
PubMed1988

Variability of the molecular defects corresponding to the presence of a Philadelphia chromosome in human hematologic malignancies.

By analyzing a total of 107 patients affected by chronic myelogenous leukemia (CML; chronic and blast crisis) or lymphoid and myeloid Philadelphia chromosome (Ph') positive acute leukemias, we have investigated the relationship between the molecular defect on the Ph' chromosome and the associated hematologic phenotype. As expected, approximately half of the Ph' positive acute leukemias showed a breakpoint on chromosome 22 falling outside the "breakpoint cluster region" (bcr) known to be involved in CML. Surprisingly, seven of 80 CML cases in chronic phase also showed rearrangements falling outside the bcr region. In two of these cases the breakpoint on chromosome 22 was mapped between 9 and 12 kb upstream to the bcr region. In another case, the breakpoint was located approximately 16 kb downstream to bcr. In the remaining four cases, the precise position of the rearrangement could not be localized with the available bcr probes. DNAs from patients with CML blast crises showed classical bcr rearrangements. No molecular changes were observed during the progression of the disease in six patients whose DNA from both a chronic and acute phase was available. Our results seem to indicate a greater degree of variability of chromosome 22 breakpoints in CML than previously observed, and the lack of additional rearrangements on the Ph' chromosome in CML blast crises with respect to chronic phase.

Adult↗
PubMed1987

Differential expression of the c-abl proto-oncogene and the homeo box-containing gene Hox 1.4 during mouse spermatogenesis.

Mammalian spermatogenesis is a complex developmental process. Spermatozoa, like ova, are uniquely capable of supporting embryonic development. Our approach to understanding this process is to identify genes whose developmental pattern of expression suggests that they may play a role in spermatogenesis. Experiments on the cellular oncogene c-abl and the homeo box-containing gene Hox-1.4 indicate that these genes may be important for male germ cell development. Both genes produce testis-specific transcripts that are present in particular cellular populations of the adult testis. Their developmental specificity, however, is different: c-abl is haploid-specific, whereas Hox-1.4 is expressed in the germ cells as soon as they have entered meiosis. Future studies will focus on examining the protein products of these genes and their function in testicular cells.

Amino Acid Sequence↗
PubMed1986

Isolation of a mouse cDNA coding for a developmentally regulated, testis-specific transcript containing homeo box homology.

A clone, pHBT-1, containing sequences homologous to Drosophila homeo boxes has been isolated from a mouse testis cDNA library. The sequence is 80% homologous at the DNA level and 88% homologous at the amino acid level to the homeo box sequence of the Antennapedia gene of Drosophila. Sequences flanking the 3' end of the homeo box are highly diverged from other murine homeo box-containing genes characterized to date. RNA blot hybridization analysis of mouse testis poly(A)+ RNA revealed transcripts of approximately 1.4 kb in length. Within the limits of sensitivity of detection of Northern blot analysis, no transcripts were seen in any of the adult somatic tissues examined. Other tissues that contain stem cells, namely those of the hemopoietic system, also lacked detectable amounts of HBT-1 transcripts. HBT-1 transcripts were limited to male germ cell-containing tissues, since RNAs from juvenile and adult ovaries did not contain detectable amounts of the 1.4-kb transcripts. Expression of the HBT-1 gene was not detected in embryonic testes, nor in tests of neonatal animals which contain germ cells up to the Type B stage of spermatogonial development. A role for the expression of the HBT-1 gene in the meiotic stages of male germ cell differentiation is postulated.

Animals↗
PubMed1985

Separation of mouse testis cells on a Celsep (TM) apparatus and their usefulness as a source of high molecular weight DNA or RNA.

The use of a self-contained unit-gravity cell separation apparatus for separation of populations of mouse testicular cells is described. The apparatus, a Celsep (TM), maximizes the unit area over which sedimentation occurs, reduces the amount of separation medium employed, and is quite reproducible. Cells thus isolated have been good sources for isolation of DNA, and notably, high molecular weight RNA.

Animals↗
PubMed1985

Haploid expression of a unique c-abl transcript in the mouse male germ line.

RNA from immature mouse testes was shown to lack a low-molecular-weight c-abl transcript previously noted to be the predominant species in adult testes. The developmental pattern of appearance of this c-abl variant was determined by analyzing RNA obtained from purified populations of testicular cells in different stages of spermatogenesis. The appearance of the c-abl testicular variant was coincident with the entry of the germ cells into their haploid state and suggested that the regulated expression of this proto-oncogene may be important in the normal differentiation of the male germ line.

Animals↗
PubMed1982

Inhibition of anaerobic glycolysis in bovine retina extracts by salicylate and acetylsalicylate.

1. Na salicylate 31 mM inhibits anaerobic glycolysis from glucose in bovine retina extracts. The formation rate of DAP and GAP increases while that of FDP, G6P, F6P and lactate decreases. All the above modifications are almost completely removed by 1.4 mM NAD+. 2. Bovine retina extracts, preincubated for 1 hr at 0 degrees C with 31 mM Na salicylate show a strongly reduced glycolytic activity. In this system G6P and F6P do accumulate, FDP, DAP, GAP and lactate decrease. These effects are not altered adding 3.5 mM NAD+ to the preincubation mixture. 3. Acetylsalicylate 31 mM inhibits anaerobic glycolysis in crude retina extracts. As the rate of lactate formation decreases, G6P and F6P do accumulate, while FDP, DAP and GAP diminish. 4. Identical modifications are observed adding the inhibitor directly to the incubation mixture, or preincubating it with the extracts at 0 degrees C for 4 hr. 3.5 mM NAD+ does not remove the effects of acetylsalicylate.

Animals↗
PubMedDate not supplied

Expression of the hybrid P210 bcr/abl protein in Philadelphia chromosome positive B-lymphoid cell lines.

An altered c-abl protein (P210) bearing increased tyrosine kinase activity represents the product of the hybrid bcr/c-abl gene arising as a consequence of the Philadelphia (Ph1) chromosome translocation, the consistent cytogenetic abnormality of chronic myelogenous leukemia (CML). Although the chronic phase of this disease is substantially characterized by a marked proliferation of myeloid cells, the Ph1 translocation occurs in an early multipotent stem cell, giving rise to both myeloid and lymphoid cell lineages. Here we show that P210 bcr/abl protein expression varies greatly in different Ph1 chromosome positive B-lymphoid cell lines obtained from Epstein-Barr virus-transformed lymphocytes of a CML patient in the chronic phase. In addition Ph1 positive and Ph1 negative lymphoid cell lines obtained from the same patient were tested for a number of biological properties including the immunophenotype, the capacity to grow in soft agar and possible tumorigenicity in nude mice. No differences were found.

Animals↗