title: Cleavage of pre-mRNA sequences by ribonucleases bound to nuclear RNP particles of rat liver.
abstract: The 30S nuclear RNP particles from rat liver have been shown to split the double-stranded- (ds) and single-stranded (ss) sequences of nuclear pre-mRNA. Experiments performed in vitro have demonstrated that 1) a 5'-exonuclease and an endonuclease specific for double-stranded pre-mRNA sequences exist in the 30S pre-mRNP particles; 2) in dsRNA monophosphorylated 5'-termini arose in the course of incubation with 30S RNP and most of the products remained double-stranded. The analysis of terminal pNp nucleotides revealed a relatively high ratio of pPyp in the cleaved dsRNA, whereas the nucleosides in 5'-terminal pNp of ssRNA showed nearly random distribution. Our results provide a possible explanation for the appearance of pNp termini during the processing of nuclear pre-mRNA of mammalian cells.
mesh_terms: D000818:Animals; D001483:Base Sequence; D002286:Carcinoma, Ehrlich Tumor; D002467:Cell Nucleus / Q000378:metabolism*; D005092:Exonucleases / Q000378:metabolism; D009690:Nucleic Acid Conformation; D009694:Nucleic Acid Precursors / Q000378:metabolism*; D009698:Nucleoproteins / Q000378:metabolism*; D012332:RNA, Heterogeneous Nuclear / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D012260:Ribonucleases / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D009694:Nucleic Acid Precursors; D009698:Nucleoproteins; D012332:RNA, Heterogeneous Nuclear; D012333:RNA, Messenger; D012261:Ribonucleoproteins; D005092:Exonucleases; D012260:Ribonucleases