THE PATTERN OF PROTHYMOSIN-ALPHA GENE-EXPRESSION COINCIDES WITH THAT OF MYC PROTOONCOGENES DURING MOUSE EMBRYOGENESIS

The nuclear protein prothymosin alpha is thought to play a critical ro le in cellular proliferation. Transcription of the gene encoding proth ymosin alpha has been shown to be activated by the proto-oncogene c-my c. Also, prothymosin alpha mRNA expression correlates with that of c-m yc in human colon cancer. We compared the previously reported embryoni c expression pattern of the proto-oncogene c-myc and the pattern of th e prothymosin alpha gene by in situ hybridization. Prothymosin alpha i s transcribed in all tissues expressing c-myc, including brown adipose tissue, salivary gland, thymus and liver. In addition, we show that t he prothymosin alpha gene is active in tissues expressing specifically N-myc such as the neuronal anlage and hair follicles in skin. Therefo re, during mouse foetal development the temporal, spatial and tisue-sp ecific expression patterns of both myc protooncogenes coincide with th e pattern of prothymosin alpha.