Developmental and tissue-specific expression of DEAD box protein p72

Retinoic acid (RA) is a vitamin A derivative that has been well documented to be involved in cell differentiation. Using RNA fingerprinting by arbitrarily primed PCR, we have previously identified a number of transcripts that are regulated during RA-induced neuronal differentiation of embryonal carcinoma NT2/D1 cells. DEAD box protein p72 is one of the clones found to be down-regulated following treatment with RA. To further investigate the regulation of p72, the mRNA expression of p72 in various neuronal cell lines and primary neuronal cultures was examined. Transcripts of p72 were reduced in differentiated PC12 and IMR-32 cells but not in SH-SY5Y cells. Partial cDNA fragments of p72 were isolated from rat and chick for the systematic analysis of p72 expression in different adult tissues and developmental stages. While prominent expression of p72 was observed in brain and testis, the expression was down-regulated in brain, muscle and liver during development. Taken together, our findings provide the first demonstration on the spatial and temporal expression profile of p72 in rat and chick tissues which is consistent with a role of p72 during early development.