title: Ngl2p is a Ccr4p-like RNA nuclease essential for the final step in 3'-end processing of 5.8S rRNA in Saccharomyces cerevisiae.
abstract: Saccharomyces cerevisiae contains three nonessential genes (NGL1, NGL2, and NGL3) that encode proteins containing a domain with similarity to a Mg(2+)-dependent endonuclease motif present in the mRNA deadenylase Ccr4p. We have investigated a possible role of these proteins in rRNA processing, because for many of the pre-rRNA processing steps, the identity of the responsible nuclease remains elusive. Analysis of RNA isolated from cells in which the NGL2 gene has been inactivated (ngl2delta) demonstrates that correct 3'-end formation of 5.8S rRNA at site E is strictly dependent on Ngl2p. No role in pre-rRNA processing could be assigned to Ngl1p and Ngl3p. The 3'-extended 5.8S rRNA formed in the ngl2delta mutant is slightly shorter than the 6S precursor previously shown to accumulate upon combined deletion of the 3' --> 5' exonuclease-encoding REX1 and REX2 genes or upon depletion of the exosomal subunits Rrp40p or Rrp45p. Thus, our data add a further component to the set of nucleases required for correct 3'-end formation of yeast 5.8S rRNA.
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D017353:Gene Deletion; D005800:Genes, Fungal; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012322:RNA Precursors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012331:RNA, Fungal / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012340:RNA, Ribosomal, 5.8S / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
chemical_list: D012322:RNA Precursors; D012331:RNA, Fungal; D012340:RNA, Ribosomal, 5.8S; D029701:Saccharomyces cerevisiae Proteins; C078657:CCR4 protein, S cerevisiae; D012260:Ribonucleases