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 p is one of the clones found to be down-regulated following treatment with RA. To further investigate the regulation of p, the mRNA expression of p in various neuronal cell lines and primary neuronal cultures was examined. Transcripts of p were reduced in differentiated PC12 and IMR-32 cells but not in SH-SY5Y cells. Partial cDNA fragments of p were isolated from rat and chick for the systematic analysis of p72 expression in different adult tissues and developmental stages. While prominent expression of p 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 p in rat and chick tissues which is consistent with a role of p during early development.