Biomedical subjects

F Esposito

Publications and source records attributed to F Esposito.

2 recordsLinked to original sources

PubMed2005

High Mobility Group A1 (HMGA1) proteins interact with p53 and inhibit its apoptotic activity.

HMGA gene overexpression and rearrangements are frequent in several tumours, but their oncogenic function is still unclear. Here we report of a physical and functional interaction between High Mobility Group A1 (HMGA1) protein and p53 oncosuppressor. We found that HMGA1 binds p53 in vitro and in vivo, and both proteins are present in the same complexes bound to the Bax gene promoter. HMGA1 interferes with the p53-mediated transcription of p53 effectors Bax and p21(waf1) while cooperates with p53 in the transcriptional activation of the p53 inhibitor mdm2. This transcriptional modulation is associated with a reduced p53-dependent apoptosis in cells expressing exogenous HMGA1 and p53, or in cells expressing endogenously the proteins and in which p53 was activated by UV-irradiation. Furthermore, antisense inhibition of HMGA1b expression dramatically increases the UV-induced p53-mediated apoptosis. These data define a new physical and functional interaction between HMGA1 and p53 that modulates transcription of p53 target genes and inhibits apoptosis.

Apoptosis↗

PubMed1979

Specific contact-dependent cell-to-cell communication during preconjugant interactions of the ciliate Euplotes crassus.

A system has been developed to study cellular interactions between cells of complementary mating types prior to mating in the ciliate, Euplotes crassus. The presumptive mates were distinguished by using singlet and doublet cells of appropriate mating types in the mixtures. Cells of a given mating type were prelabelled with [3H]leucine and mixed with unlabelled complementary cells. Exchange of [3H]leucine-labelled material from donor to recipient cells was monitored through the various stages of the preconjugant interaction. A label transfer between the mating type complementary cells was detected from the beginning of the visible mating reaction, which occurs after a waiting period from the time of cell mixing and involves ciliary agglutination prior to cell body fusion. Complementary cells which were prevented from physically contacting each other and cells which were not competent to mate appeared unable to take up the labelled material. It is suggested that this material consists of some substance(s) playing an important role in the preconjugant cell-to-cell interactions of E. crassus.

Animals↗