title: [Destruction of mRNA poly-A sequences by polynucleotide phosphorylase in rat liver microsomes].
abstract: A possible role of polynucleotide phosphorylase (PNPase) in the destruction of poly-A fragments located at the 3'-OH end of mRNA from rat liver polyribosomes was studied. Using hybridization of mRNP particles and mRNA with poly-U Sepharose 4B, it was found that polyribosomal PNPase in vitro destroys the poly-A sequences of approximately 25% of poly-A+ mRNA during the first minutes of incubation at a high rate. The destruction of the poly-A fragment of mRNA by PNPase is incomplete, since part of it is presumably protected by proteins firmly bound to the poly-A sequences of mRNA.
mesh_terms: D000818:Animals; D008862:Microsomes, Liver / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D011061:Poly A / Q000378:metabolism*; D011117:Polyribonucleotide Nucleotidyltransferase / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D012261:Ribonucleoproteins / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D012261:Ribonucleoproteins; D011061:Poly A; D011117:Polyribonucleotide Nucleotidyltransferase
vernacular_title: Rzrushenie polinykleotidfosforilazoĭ poli-A-posledovatel'nostei mRNK v poliribosomakh iz pecheni krysy.