ARD-1 cDNA from human cells encodes a site-specific single-strand endoribonuclease that functionally resembles Escherichia coli RNase E.
The human ARD-1 (activator of RNA decay) cDNA sequence can rescue mutations in the Escherichia coli rne gene, which specifies the essential endoribonuclease RNase E, resulting in RNase E-like cleavages in vivo in rne-defective bacteria and in vitro in extracts isolated from these cells (Wang, M., and Cohen, S. N. (1994) Proc. Natl. Acad. Sci. U. S. A. 91, 10591-10595). Recent studies indicate that the 13.3-kDa protein encoded by ARD-1 cDNA is almost identical to the carboxyl-terminal end of the bovine protein NIPP-1, a nuclear inhibitor of protein phosphatase 1; separate transcripts formed by alternative splicing are proposed to encode the discrete ARD-1 and combined ARD-1/NIPP-1 products (Van Eynde, A., Wera, S., Beullens, M. , Torrekens, S., Van Leuven, F., Stalmans, W., and Bollens, M. (1995) J. Biol. Chem. 270, 28068-28074). Here we show that affinity column-purified protein encoded by human ARD-1 cDNA in E. coli is a site-specific Mg2+-dependent endoribonuclease that binds in vitro to RNase E substrates, cleaves RNA at the same sites as RNase E, and, like RNase E, generates 5' phosphate termini at sites of cleavage. Our results indicate that the ARD-1 peptide can function as a ribonucleolytic analog of E. coli RNase E as well as a domain of the protein phosphatase inhibitor, NIPP-1.
Claverie-Martin
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Department of Genetics, Stanford University School of Medicine, Stanford, California 94305-5120, USA.
Wang
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Cohen
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D000818:Animals; D002352:Carrier Proteins; D002417:Cattle; D018076:DNA, Complementary / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004722:Endoribonucleases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008274:Magnesium / Q000378:metabolism; D009843:Oligoribonucleotides / Q000378:metabolism; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D011506:Proteins / Q000378:metabolism; D012329:RNA, Bacterial / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D012259:Ribonuclease, Pancreatic / Q000378:metabolism
D002352:Carrier Proteins; D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D009843:Oligoribonucleotides; D011506:Proteins; D012329:RNA, Bacterial; D016601:RNA-Binding Proteins; C021042:protein phosphatase inhibitor-1; D004722:Endoribonucleases; D012259:Ribonuclease, Pancreatic; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; C097081:PPP1R8 protein, human; C022537:ribonuclease E; D008274:Magnesium