The BRCT domain of mammalian Pes1 is crucial for nucleolar localization and rRNA processing.
The nucleolar protein Pes1 interacts with Bop1 and WDR12 in a stable complex (PeBoW-complex) and its expression is tightly associated with cell proliferation. The yeast homologue Nop7p (Yph1p) functions in both, rRNA processing and cell cycle progression. The presence of a BRCT-domain (BRCA1 C-terminal) within Pes1 is quite unique for an rRNA processing factor, as this domain is normally found in factors involved in DNA-damage or repair pathways. Thus, the function of the BRCT-domain in Pes1 remains elusive. We established a conditional siRNA-based knock-down-knock-in system and analysed a panel of Pes1 truncation mutants for their functionality in ribosome synthesis in the absence of endogenous Pes1. Deletion of the BRCT-domain or single point mutations of highly conserved residues caused diffuse nucleoplasmic distribution and failure to replace endogenous Pes1 in rRNA processing. Further, the BRCT-mutants of Pes1 were less stable and not incorporated into the PeBoW-complex. Hence, the integrity of the BRCT-domain of Pes1 is crucial for nucleolar localization and its function in rRNA processing.
Hölzel
Michael
M
Institute of Clinical Molecular Biology and Tumour Genetics, GSF Research Centre, Marchioninistrasse 25, 81377 Munich, Germany. hoelzel@gsf.de
Grimm
Thomas
T
Rohrmoser
Michaela
M
Malamoussi
Anastassia
A
Harasim
Thomas
T
Gruber-Eber
Anita
A
Kremmer
Elisabeth
E
Eick
Dirk
D
D045744:Cell Line, Tumor; D002466:Cell Nucleolus / Q000737:chemistry*; D006801:Humans; D009687:Nuclear Proteins / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism*; D017354:Point Mutation; D017434:Protein Structure, Tertiary / Q000235:genetics; D011506:Proteins / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism*; D034622:RNA Interference; D012323:RNA Processing, Post-Transcriptional; D012335:RNA, Ribosomal / Q000378:metabolism*; D016601:RNA-Binding Proteins; D017384:Sequence Deletion
D009687:Nuclear Proteins; C484463:PES1 protein, human; D011506:Proteins; D012335:RNA, Ribosomal; D016601:RNA-Binding Proteins