The vertebrate E1/U17 small nucleolar ribonucleoprotein particle

Abstract

Each of the many different box H/ACA ribonucleoprotein particles (RNPs) present in eukaryotes and archaea consists of four common core proteins and one specific H/ACA small RNA, which bears the sequence elements H (ANANNA) and ACA. Most of the H/ACA RNPs are small nucleolar RNPs (snoRNPs), which are localized in nucleoli, and are one of the two major classes of snoRNPs. Most H/ACA RNPs direct pseudouridine synthesis in pre-rRNA and other RNAs. One H/ACA small nucleolar RNA (snoRNA), vertebrate E1/U17 (snR30 in yeast), is required for pre-rRNA cleavage processing that generates mature 18S rRNA. E1 snoRNA is encoded in introns of protein-coding genes, and the evidence suggests that human E1 RNA undergoes uridine insertional RNA editing. The vertebrate E1 RNA consensus secondary structure shows several features that are absent in other box H/ACA snoRNAs. The available UV-induced RNA-protein crosslinking results suggest that the E1 snoRNP is asymmetrical in vertebrate cells, in contrast to other H/ACA snoRNPs. The vertebrate E1 snoRNP in cells is surprisingly complex: (i) E1 RNA contacts directly and specifically several proteins which do not appear to be any of the H/ACA RNP four core proteins; and (ii) multiple E1 RNA sites are needed for E1 snoRNP formation, E1 RNA stability, and E1 RNA-protein direct interactions.

RNA-based affinity purification reveals 7SK RNPs with distinct composition and regulation

“…(Eliceiri 2006), was tagged at the 59 end with hairpins in the PT order. One-tenth of the material bound to washed tobramycin resin was used for SDS-PAGE and silver staining.…”

Noncoding RNAs of the H/ACA Family

“…U17/snR30 is the only H/ACA RNA whose sequence is conserved among diverse eukaryotes, and two conserved antisense sequence elements that are essential for pre-18S rRNA cleavages have been identified (Morrissey and Tollervey 1993). These elements are located in the 3h airpin on opposite strands of the equivalent of the pseudouridine pocket (Cervelli et al 2002;Atzorn et al 2004;Eliceiri 2006). as detailed below (Hamma and Ferre-D'Amare 2004).…”

The Box H/ACA Ribonucleoprotein Complex: Interplay of RNA and Protein Structures in Post-transcriptional RNA Modification

“…Although the biological function of ⌿ is likely to be different for each of its occurrences, its importance for correct function of tRNA, the ribosome, and the spliceosome is well documented (reviewed in Refs. [11][12][13][14].…”