32S pre-rRNA processing: a dynamic model for interaction with U3RNA and structural rearrangements of spacer regions.
A model of rearrangement of 32S pre-rRNA during processing was proposed. The first step of these events is the cotranscriptional interaction of the 3'-half of 5.8S rRNA and adjacent part of the internal transcribed spacer (ITS-2) with the 3'-part of the small nucleolar U3RNA from its 155th to 215th nucleotides (numbered for a rat U3RNA). This interaction prevents formation of intramolecular double-stranded structure between 5'-and 3'-end sequences of 5.8S rRNA. The second step is the appearance of extended hairpin structures in the ITS-2, which leads to a compactisation of the entire 32S-pre-rRNA molecule and to the complex formation between 5.8S rRNA and 28S rRNA sequences as the result of U3RNA displacing. After elimination of ITS-2 sequences from 32S pre-rRNA this complex can be included into ribosomes.
Kupriyanova
N S
NS
Institute of Molecular Biology, USSR Academy of Sciences, Moscow.
Timofeeva MYa
D000818:Animals; D001483:Base Sequence; D006801:Humans; D008956:Models, Chemical; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D012342:RNA, Small Nuclear / Q000378:metabolism*; D014158:Transcription, Genetic
D012322:RNA Precursors; D012342:RNA, Small Nuclear