Studies of the strand-annealing activity of mammalian hnRNP complex protein A1.
A1 is a major core protein of the mammalian hnRNP complex, and as a purified protein of approximately 34 kDa, A1 is a strong single-stranded nucleic acid binding protein. Several lines of evidence suggest that the protein is organized in discrete domains consisting of an N-terminal segment of approximately 22 kDa and a C-terminal segment of approximately 12 kDa. Each of these domains as a purified fragment is capable of binding to both ssDNA and RNA. We report here that A1 and its C-terminal domain fragment are capable of potent strand-annealing activity for base-pair complementary single-stranded polynucleotides of both RNA and DNA. This effect is not stimulated by ATP. Compared with A1 and the C-terminal fragment, the N-terminal domain fragment has negligible annealing activity. These results indicate that A1 has biochemical activity consistent with a strand-annealing role in relevant reactions, such as pre-mRNA splicing.
Laboratory of Biochemistry, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.
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Kumar
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Wilson
D000818:Animals; D010584:Bacteriophage phi X 174; D004247:DNA / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000378:metabolism*; D004279:DNA, Viral / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D008970:Molecular Weight; D009693:Nucleic Acid Hybridization; D010446:Peptide Fragments / Q000378:metabolism; D012313:RNA / Q000378:metabolism*; D051381:Rats; D011938:Rec A Recombinases / Q000378:metabolism; D012261:Ribonucleoproteins / Q000032:analysis*
D004277:DNA, Single-Stranded; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D010446:Peptide Fragments; D012261:Ribonucleoproteins; D012313:RNA; D004247:DNA; D011938:Rec A Recombinases