title: Trypanosome MTR4 is involved in rRNA processing.
abstract: The yeast putative RNA helicase Mtr4p is implicated in exosome-mediated RNA quality control in the nucleus, interacts with the exosome, and is found in the 'TRAMP' complex with a yeast nuclear poly(A) polymerase (Trf4p/Pap2p or Trf5p) and a putative RNA-binding protein, Air1p or Air2p. Depletion of the Trypanosoma brucei MTR4-like protein TbMTR4 caused growth arrest and defects in 5.8S rRNA processing similar to those seen after depletion of the exosome. TbNPAPL, a nuclear protein which is a putative homolog of Trf4p/Pap2p, was required for normal cell growth. Depletion of MTR4 resulted in the accumulation of polyadenylated rRNA precursors, while depletion of TbNPAPL had little effect. These results suggest that polyadenylation-dependent nuclear rRNA quality control is conserved in eukaryotic evolution. In contrast, there was no evidence for a trypanosome TRAMP complex since no stable interactions between TbMTR4 and the exosome, TbNPAPL or RNA-binding proteins were detected.
authors.affiliation: Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Im Neuenheimer Feld 282, 69120 Heidelberg, Germany.
authors.forename: Marina
authors.initials: M
authors.lastname: Cristodero
authors.forename: Christine E
authors.initials: CE
authors.lastname: Clayton
mesh_terms: D000818:Animals; D020365:RNA Helicases / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D012335:RNA, Ribosomal / Q000378:metabolism*; D014346:Trypanosoma brucei brucei / Q000235:genetics / Q000378:metabolism
chemical_list: D012335:RNA, Ribosomal; D020365:RNA Helicases