Rio1 mediates ATP-dependent final maturation of 40S ribosomal subunits.

ABSTRACT: During the last step in 40S ribosome subunit biogenesis, the PIN-domain endonuclease Nob1 cleaves the 20S pre-rRNA at site D, to form the mature 18S rRNAs. Here we report that cleavage occurs in particles that have largely been stripped of previously characterized pre-40S components, but retain the endonuclease Nob1, its binding partner Pno1 (Dim2) and the atypical ATPase Rio1. Within the Rio1-associated pre-40S particles, in vitro pre-rRNA cleavage was strongly stimulated by ATP and required nucleotide binding by Rio1. In vivo binding sites for Rio1, Pno1 and Nob1 were mapped by UV cross-linking in actively growing cells. Nob1 and Pno1 bind overlapping regions within the internal transcribed spacer 1, and both bind directly over cleavage site D. Binding sites for Rio1 were within the core

SUBMITTER: Turowski TW 

PROVIDER: S-EPMC4231747 | biostudies-literature | 2014 Oct

REPOSITORIES: biostudies-literature