The pattern of prothymosin alpha gene expression coincides with that of myc proto-oncogenes during mouse embryogenesis.

The nuclear protein prothymosin alpha is thought to play a critical role in cellular proliferation. Transcription of the gene encoding prothymosin alpha has been shown to be activated by the proto-oncogene c-myc. Also, prothymosin alpha mRNA expression correlates with that of c-myc in human colon cancer. We compared the previously reported embryonic expression pattern of the proto-oncogene c-myc and the pattern of the prothymosin alpha gene by in situ hybridization. Prothymosin alpha is transcribed in all tissues expressing c-myc, including brown adipose tissue, salivary gland, thymus and liver. In addition, we show that the prothymosin alpha gene is active in tissues expressing specifically N-myc such as the neuronal anlage and hair follicles in skin. Therefore, during mouse foetal development the temporal, spatial and tissue-specific expression patterns of both myc proto-oncogenes coincide with the pattern of prothymosin alpha.