EXPRESSION OF THE DEAD BOX RNA HELICASE P68 IS DEVELOPMENTALLY AND GROWTH-REGULATED AND CORRELATES WITH ORGAN DIFFERENTIATION MATURATION INTHE FETUS/

The human DEAD bos protein p68 is an established RNA-dependent ATPase and RNA helicase, p68 has been highly conserved in evolution and appea rs to be essential for normal growth, suggesting that this protein pla ys an important role in the cell. Although the biochemical activities of p68 are fairly well characterized, little is known about its biolog ical function. This report shows that p68 is detectable in quiescent c ell lines, but its expression is induced by serum, suggesting that thi s protein may play a role in cell growth. It is also shown that both p 68 mRNA and protein are differentially expressed in adult tissues; in this case, however, the levels do not always correlate with proliferat ion status, suggesting that the regulation of expression in the animal may be different from that in cell lines. Finally, it is shown that p 68 expression is developmentally regulated and appears to correlate wi th organ differentiation/maturation. These findings suggest that p68 e xpression may not simply reflect proliferation/differentiation status and that it appears to be regulated in a more complex may. (C) 1998 Jo hn Wiley & Sons, Ltd.