Human RNA helicase A is homologous to the maleless protein of Drosophila.
RNA helicase A is an abundant nuclear enzyme of HeLa cells that unwinds double-stranded RNA in a 3' to 5'direction (Lee, C. G., and Hurwitz, J. (1992) J. Biol. Chem. 267, 4398-4407). A complementary DNA (cDNA) clone expressing RNA helicase A was isolated by screening a human cDNA library with polyclonal antibodies produced against the purified protein. The deduced amino acid sequence from this clone showed that RNA helicase A is a member of the DEAH family of proteins thought to be helicases. Sequence comparison among all known proteins of the DEAH family revealed that the highest homology was between RNA helicase A and the maleless protein (MLE) of Drosophila. There was 49% identity and 85% similarity throughout the overall primary sequences of both proteins, suggesting that RNA helicase A is the human counterpart of Drosophila MLE. Polyclonal antibodies against Drosophila MLE recognized RNA helicase A in crude nuclear extracts of HeLa cells as well as the purified protein. A recombinant RNA helicase A containing 6 histidine residues at the NH2 terminus was expressed in Sf9 cells using a baculovirus vector. The protein isolated from insect cells and the enzyme purified from HeLa cells exhibited identical RNA helicase and RNA-dependent ATPase activities.
Lee
C G
CG
Graduate Program in Molecular Biology, Memorial Sloan-Kettering Cancer Center, Sloan-Kettering Institute, New York, New York 10021.
Hurwitz
J
J
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002460:Cell Line; D002868:Chromosomal Proteins, Non-Histone; D004247:DNA; D004265:DNA Helicases; D004268:DNA-Binding Proteins; D004330:Drosophila; D029721:Drosophila Proteins; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D008969:Molecular Sequence Data; D009036:Moths; D009687:Nuclear Proteins / Q000235:genetics*; D020365:RNA Helicases; D012316:RNA Nucleotidyltransferases / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics*
D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; C070837:mle protein, Drosophila; D004247:DNA; D012316:RNA Nucleotidyltransferases; D004265:DNA Helicases; D020365:RNA Helicases