Probable ATP-binding RNA helicase. Plays an essential role in early embryonic development. ATP + H2O = ADP + H(+) + phosphate The Q motif is unique to and characteristic of the DEAD box family of RNA helicases and controls ATP binding and hydrolysis. Embryos have bent ceratohyal cartilage. Belongs to the DEAD box helicase family. DDX55/SPB4 subfamily.