Lsm Proteins are required for normal processing and stability of ribosomal RNAs.
Depletion of any of the essential Lsm proteins, Lsm2-5p or Lsm8p, delayed pre-rRNA processing and led to the accumulation of many aberrant processing intermediates, indicating that an Lsm complex is required to maintain the normally strict order of processing events. In addition, high levels of degradation products derived from both precursors and mature rRNAs accumulated in Lsm-depleted strains. Depletion of the essential Lsm proteins reduced the apparent processivity of both 5' and 3' exonuclease activities involved in 5.8S rRNA processing, and the degradation intermediates that accumulated were consistent with inefficient 5' and 3' degradation. Many, but not all, pre-rRNA species could be coprecipitated with tagged Lsm3p, but not with tagged Lsm1p or non-tagged control strains, suggesting their direct interaction with an Lsm2-8p complex. We propose that Lsm proteins facilitate RNA protein interactions and structural changes required during ribosomal subunit assembly.
Kufel
Joanna
J
Wellcome Trust Centre for Cell Biology, Swann Building, King's Buildings, University of Edinburgh, United Kingdom.
Allmang
Christine
C
Petfalski
Elisabeth
E
Beggs
Jean
J
Tollervey
David
D
D001483:Base Sequence; D015152:Blotting, Northern; D017353:Gene Deletion; D005838:Genotype; D008957:Models, Genetic; D008969:Molecular Sequence Data; D063211:N-Terminal Acetyltransferase C; D010641:Phenotype; D011233:Precipitin Tests; D012313:RNA / Q000378:metabolism; D039381:RNA Cap-Binding Proteins; D012333:RNA, Messenger / Q000378:metabolism; D012335:RNA, Ribosomal / Q000378:metabolism*; D012337:RNA, Ribosomal, 18S / Q000378:metabolism; D012340:RNA, Ribosomal, 5.8S / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D017414:Ribonucleoprotein, U4-U6 Small Nuclear / Q000235:genetics / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology*
C114069:LSM1 protein, S cerevisiae; C117009:NAA38 protein, human; D039381:RNA Cap-Binding Proteins; D012333:RNA, Messenger; D012335:RNA, Ribosomal; D012337:RNA, Ribosomal, 18S; D012340:RNA, Ribosomal, 5.8S; D016601:RNA-Binding Proteins; D017414:Ribonucleoprotein, U4-U6 Small Nuclear; D029701:Saccharomyces cerevisiae Proteins; D012313:RNA; D063211:N-Terminal Acetyltransferase C