Article Dans Une Revue Biology of Reproduction Année : 2001

Status of p53, p21, mdm2, pRb Proteins, and DNA Methylation in Gonocytes of Control and γ-Irradiated Rats During Testicular Development1

Résumé

In fetal and newborn rat testes, gonocytes, which stop cycling for about 8 days, become highly radiosensitive. The presence of p53, p21, mdm2, and pRb, which are involved in cell cycle, apoptosis control, or both, were studied by immunohistochemistry to determine if their expression is related to this radiosensitivity. A strong cytoplasmic expression of p53 and p21 was detected. Cytoplasmic expression of p53 occurred only in arrested gonocytes, whereas that of p21 was observed before and after the block. P21 was found to colocalize with mitochondria. No expression of mdm2 was detected and pRb was present only when the gonocytes started cycling again. In animals exposed to 1.5 Gy of gamma-irradiation at Day 19 postcoitum, p53 expression was prolonged in time, whereas no change was observed in p21 amounts and localization, compared with controls. Using antibodies against 5-methyl cytosine, it was shown that gonocyte DNA passed from a hypomethylated to a methylated status 1 day after gonocytes stopped cycling. A prolonged survival of gonocytes after exposure to radiation was followed by their progressive apoptosis, which finally involved the entire gonocyte population between Days 6 and 12 postpartum. The elevated but delayed sensitivity of gonocytes to genotoxic stress may be related to the unusual expression of p53 and p21, which may itself be related to the large DNA methylation changes.

Fichier non déposé

Dates et versions

hal-04251894 , version 1 (20-10-2023)

Identifiants

Citer

Stéphanie G. Moreno, Bernard Dutrillaux, Hervé Coffigny. Status of p53, p21, mdm2, pRb Proteins, and DNA Methylation in Gonocytes of Control and γ-Irradiated Rats During Testicular Development1. Biology of Reproduction, 2001, 64 (5), pp.1422-1431. ⟨10.1095/biolreprod64.5.1422⟩. ⟨hal-04251894⟩

Collections

26 Consultations
0 Téléchargements

Altmetric

Partager

  • More