The DEAD box RNA helicases p68 (Ddx5) and p72 (Ddx17): novel transcriptional co-regulators.

DEAD box [a motif named after its amino acid sequence (Asp-Glu-Ala-Asp)] RNA helicases are known to play key roles in all cellular processes that require modulation of RNA structure. However, in recent years, several of these proteins have been found to function in transcriptional regulation. In the present paper, we shall review the literature demonstrating the action of p68 and, where data are available, p72 as transcriptional co-regulators for a range of transcription factors, namely ERalpha (oestrogen receptor alpha), the tumour suppressor p53, the myogenic regulator MyoD and Runx2, a transcription factor essential for osteoblast development. We shall also discuss evidence indicating that, in some cases at least, p68 and p72 have distinct, non-redundant, roles.