Prothymosin alpha is a nuclear protein

Prothymosin alpha expression is associated to cell division in rat testis

Using immunohistochemical methods, we have investigated the cellular distribution of prothymosin alpha (ProT) in adult rat testis. A policlonal antibody raised against thymosin alpha 1 conjugated to keyhole limpet hemocyanin was used. ProT immunoreactivity was observed in the cytoplasm and nucleus of spermatogonia and primary spermatocytes in initial phases of the first meiotic division, preleptotene, leptotene and zygotene. However, in pachytene phase they already showed a weak or negative staining. On the other hand, secondary spermatocytes, spermatids, spermatozoa and Sertoli cells were not stained. Based on this fact we suggest that ProT is present in the proliferative cycle in the final steps of G1 phase, throughout the S and G2 phases and in initial steps of the prophase.

Prothymosin alpha is an evolutionary conserved protein covalently linked to a small RNA

A 13 kDa protein, covalently linked to a small RNA from the cytoplasm of mouse cells, was studied. Sequence analysis of its tryptic peptides revealed that the RNA-linked protein is identical to prothymosin alpha. Very similar RNA-protein complexes were identified in human, bovine and yeast cells. Tryptic peptide maps of 125I-labelled RNA-linked proteins of diverse origin demonstrated their marked similarity, thus indicating high evolutionary conservation of prothymosin alpha from yeast to man.