In mutant studies, the apparently redundant role(s) of p68 and p72/p82 correspond to their ability to catalyze RNA rearrangement rather than RNA unwinding reactions.     ///    We found that p68 negatively controls p72/p82 gene expression but not vice versa.     ///    Redundant role of DEAD box proteins p68 (Ddx5) and p72/p82 (Ddx17) in ribosome biogenesis and cell proliferation..     ///    "Knocking down of either gene does not affect cell proliferation, in case of p68 suppression, however, only on condition that p72/p82 overexpression was granted. "