title: Ribonuclease V of escherichia coli. I. Dependence on ribosomes and translocation.
abstract: A new RNase activity, tentatively named RNase V, was found in cell-free extracts of E. coli. This activity requires ribosomes, G and T factors, tRNA, K(+) or NH(4) (+), Mg(2+), GTP, and a sulfhydryl compound to degrade poly U, poly A, T4 phage mRNA, or E. coli mRNA. RNase V is specific for mRNA; it does not attack ribosomal RNA. It is inhibited by antibiotics that decrease breakdown of mRNA in vivo, such as chloramphenicol and streptomycin, and by such agents as 5'-beta, gamma-methylene-guanosine triphosphate, and fusidic acid, which inhibit ribosome-dependent GTPase and translocation of ribosomes along mRNA. The evidence suggests that RNase V is either an integral part of the ribosome or is tightly associated with it, and that it selectively degrades mRNA in intact cells.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002474:Cell-Free System; D002499:Centrifugation, Density Gradient; D002845:Chromatography; D004926:Escherichia coli / Q000201:enzymology*; D011119:Polynucleotides / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012260:Ribonucleases / Q000378:metabolism*; D012270:Ribosomes / Q000201:enzymology*
chemical_list: D000900:Anti-Bacterial Agents; D011119:Polynucleotides; D012333:RNA, Messenger; D012260:Ribonucleases