A Xenopus zinc finger protein that specifically binds dsRNA and RNA-DNA hybrids.
Proteins containing C2H2 type zinc finger motifs represent one of the largest classes of nucleic acid-binding proteins found in nature. We describe a novel zinc finger protein, dsRBP-ZFa, isolated by screening an expression library with dsRNA. The dsRBP-ZFa cDNA encodes a protein containing seven zinc finger motifs and an acidic C-terminal domain. Mobility shift experiments demonstrate that dsRBP-ZFa binds dsRNA and RNA-DNA hybrids with nanomolar dissociation constants and in a sequence independent manner. We also show that DNA and single stranded RNA fail to compete with dsRNA for binding suggesting dsRBP-ZFa prefers to bind an A-form helix. Using western analyses we have localized dsRBP-ZFa primarily to the nucleus of Xenopus laevis oocytes. The identification of dsRBP-ZFa provides the first example of a zinc finger protein that is specific for dsRNA. In addition, dsRBP-ZFa does not contain the previously described dsRNA binding motif, suggesting certain zinc fingers may provide an alternative way to recognize the A-form helix.
Finerty
P J
PJ
Department of Biochemistry and Howard Hughes Medical Institute, 6110a EIHG, Salt Lake City, UT, 84112, USA.
Bass
B L
BL
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins; D004926:Escherichia coli; D015723:Gene Library; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes; D016366:Open Reading Frames; D016133:Polymerase Chain Reaction; D017433:Protein Structure, Secondary; D012313:RNA / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D014981:Xenopus; D029867:Xenopus Proteins; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; D015345:Oligonucleotide Probes; D012330:RNA, Double-Stranded; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D029867:Xenopus Proteins; C108057:dsRBP-ZFa protein, Xenopus; D012313:RNA; D004247:DNA