The presence of a p53-like protein during pea seed maturation and germination

The mechanisms that allow monitoring of DNA damage and the activation of re pair systems in plants are poorly known. In mammalian cells the tumor suppr essor protein p53 plays an important role in the checkpoint pathway induced by DNA damage. In this work, me investigated the presence and distribution of the p53-like protein in pea root tip nuclei and its role during early g ermination in relation to DNA damage. In pea seed, PFGE and TdT assays show that DNA fragmentation occurs during maturation and dry seed storage, and that this DNA fragmentation is repaired at the beginning of germination bef ore the onset of proliferation. In the same seeds, the p53-like protein was found during maturation and germination. Immunoblotting characterization o f this protein led to the identification of a single specific protein of ab out 94 kDa, more abundant at the beginning of the hydration process than in actively cycling cells. Furthermore, the p53-like protein revealed differe nt nuclear distribution patterns, probably in relation to the formation of DNA fragments in dry seeds, and to the reactivation of repair mechanisms du ring early germination. These data suggest that the presence of a p53-like protein in quiescent or proliferating, pea embryo is related to DNA damage, and serves for the maintenance of genetic information and the development of normal seedlings.