Interactions between subunits of Saccharomyces cerevisiae RNase MRP support a conserved eukaryotic RNase P/MRP architecture.
Ribonuclease MRP is an endonuclease, related to RNase P, which functions in eukaryotic pre-rRNA processing. In Saccharomyces cerevisiae, RNase MRP comprises an RNA subunit and ten proteins. To improve our understanding of subunit roles and enzyme architecture, we have examined protein-protein and protein-RNA interactions in vitro, complementing existing yeast two-hybrid data. In total, 31 direct protein-protein interactions were identified, each protein interacting with at least three others. Furthermore, seven proteins self-interact, four strongly, pointing to subunit multiplicity in the holoenzyme. Six protein subunits interact directly with MRP RNA and four with pre-rRNA. A comparative analysis with existing data for the yeast and human RNase P/MRP systems enables confident identification of Pop1p, Pop4p and Rpp1p as subunits that lie at the enzyme core, with probable addition of Pop5p and Pop3p. Rmp1p is confirmed as an integral subunit, presumably associating preferentially with RNase MRP, rather than RNase P, via interactions with Snm1p and MRP RNA. Snm1p and Rmp1p may act together to assist enzyme specificity, though roles in substrate binding are also indicated for Pop4p and Pop6p. The results provide further evidence of a conserved eukaryotic RNase P/MRP architecture and provide a strong basis for studies of enzyme assembly and subunit function.
Aspinall
Tanya V
TV
Faculty of Life Sciences, Manchester Interdisciplinary Biocentre, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.
Gordon
James M B
JM
Bennett
Hayley J
HJ
Karahalios
Panagiotis
P
Bukowski
John-Paul
JP
Walker
Scott C
SC
Engelke
David R
DR
Avis
Johanna M
JM
D004722:Endoribonucleases / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D025941:Protein Interaction Mapping; D021122:Protein Subunits / Q000302:isolation & purification; D012322:RNA Precursors / Q000378:metabolism; D012331:RNA, Fungal / Q000378:metabolism; D012335:RNA, Ribosomal / Q000378:metabolism; D043262:Ribonuclease P / Q000378:metabolism; D012261:Ribonucleoproteins / Q000302:isolation & purification / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins / Q000302:isolation & purification / Q000378:metabolism*
D021122:Protein Subunits; D012322:RNA Precursors; D012331:RNA, Fungal; D012335:RNA, Ribosomal; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; D004722:Endoribonucleases; C058330:mitochondrial RNA-processing endoribonuclease; D043262:Ribonuclease P