Acts as an ATP-dependent RNA helicase, able to unwind both RNA-RNA and RNA-DNA duplexes. Possesses 5' single-stranded RNA overhang nuclease activity. Acts as a positive regulator of transcription. May be involved in 3'-end cleavage and polyadenylation of pre-mRNAs. Binds DNA and RNA. Component of the tRNA-splicing ligase complex required to facilitate the enzymatic turnover of catalytic subunit RTCB (By similarity). Binds (via helicase ATP-binding domain) on both short and long poly(I:C) dsRNA (By similarity). ATP + H2O = ADP + H(+) + phosphate Detected in embryonic retina, brain, heart and liver (at protein level). Detected in embryonic retina, brain, heart, kidney and liver. The helicase domain is involved in the stimulation of RELA transcriptional activity. Belongs to the DEAD box helicase family. DDX1 subfamily.