InterPro domain: IPR016819

This entry represents the Pop5 from eukaryotes and related proteins from archaea.

Ribonuclease P (Rnp) is a ubiquitous ribozyme that catalyzes a Mg2 -dependent hydrolysis to remove the 5'-leader sequence of precursor tRNA (pre-tRNA) in all three domains of life [ 1 ]. In bacteria, the catalytic RNA (typically ~120kDa) is aided by a small protein cofactor (~14kDa) [ 2 ]. Archaeal and eukaryote RNase P consist of a single RNA and archaeal RNase P has four or five proteins, while eukaryotic RNase P consists of 9 or 10 proteins. Eukaryotic and archaeal RNase P RNAs cooperatively function with protein subunits in catalysis [ 3 ].

Eukaryotic nuclear RNase P shares most of its protein components with another essential RNP enzyme, nucleolar RNase MRP [ 4 ]. RNase MRP (mitochondrial RNA processing) is an rRNA processing enzyme that cleaves various RNAs, including ribosomal, messenger, and mitochondrial RNAs. It can cleave a specific site within precursor rRNA to generate the mature 5'-end of 5.8S rRNA [ 4 ]. Despite its name, the vast majority of RNase MRP is localized in the nucleolus [ 5 ]. RNase MRP has been shown to cleave primers for mitochondrial DNA replication and CLB2 mRNA. In yeast, RNase MRP possesses one putatively catalytic RNA and at least 9 protein subunits (Pop1, Pop3-Pop8, Rpp1, Snm1 and Rmp1) [ 6 ]. Human RNase MRP complex consists of 267 nucleotides and supports the interaction with and among at least seven protein components: hPop1, hPop5, Rpp20, Rpp25, Rpp30, Rpp38, and Rpp40) and three additional proteins, hPop4, Rpp21 and Rpp14, have been reported to be associated with at least a subset of RNase MRP complexes [ 7 ].

1. The nucleotide sequence of chromosome I from Saccharomyces cerevisiae. Proc. Natl. Acad. Sci. U.S.A. 92, 3809-13
2. Chance and necessity in the evolution of RNase P. RNA 24, 1-5
3. Rpp14 and Rpp29, two protein subunits of human ribonuclease P. RNA 5, 153-7
4. Probing the structure of Saccharomyces cerevisiae RNase MRP. Biochem. Soc. Trans. 33, 479-81
5. Of proteins and RNA: the RNase P/MRP family. RNA 16, 1725-47
6. Accumulation of noncoding RNA due to an RNase P defect in Saccharomyces cerevisiae. RNA 17, 1441-50
7. RNase MRP and disease. Wiley Interdiscip Rev RNA 1, 102-16