Cellular studies of MrDb (DDX18)

Helicases are present in viruses, prokaryotes, and eukaryotes, and several of them have been linked to human diseases. Here we study the role of one putative DEAD-box RNA helicase, MrDb (DDX18), in tumor cells. We show that MrDb is a nucleolar protein ubiquitously expressed in tumor cells and that it is more abundantly expressed in proliferating cells. Inhibition of MrDb with dominant negative mutant or a shRNA reduces tumor cell proliferation without inducing a cell cycle arrest or apoptosis. These findings suggest that MrDb is important for cell proliferation and that its inhibition could prevent tumor cell proliferation.