Gar1 is a small nucleolar RNP that is required for pre-mRNA processing and pseudouridylation [1]. It is co-immunoprecipitated with the H/ACA families of snoRNAs. This family represents the conserved central region of Gar1. This region is necessary and sufficient for normal cell growth, and specifically binds two snoRNAs snR10 and snR30. This region is also necessary for nucleolar targeting, and it is thought that the protein is co-transported to the nucleolus as part of a nucleoprotein complex [2]. In humans, Gar1 is also component of telomerase in vivo [3]. Naf1 is an essential protein that plays a role in ribosome biogenesis, modification of spliceosomal small nuclear RNAs and telomere synthesis, and is homologous to Gar1 [4].

1: Ribosome synthesis in Saccharomyces cerevisiae. Venema J, Tollervey D; Annu Rev Genet 1999;33:261-311. PMID:10690410

2: Gar1p binds to the small nucleolar RNAs snR10 and snR30 in vitro through a nontypical RNA binding element. Bagni C, Lapeyre B; J Biol Chem 1998;273:10868-10873. PMID:9556561

3: In vitro assembly of human H/ACA small nucleolar RNPs reveals unique features of U17 and telomerase RNAs. Dragon F, Pogacic V, Filipowicz W; Mol Cell Biol 2000;20:3037-3048. PMID:10757788

4: The box H/ACA RNP assembly factor Naf1p contains a domain homologous to Gar1p mediating its interaction with Cbf5p. Leulliot N, Godin KS, Hoareau-Aveilla C, Quevillon-Cheruel S, Varani G, Henry Y, Van Tilbeurgh H; J Mol Biol. 2007;371:1338-1353. PMID:17612558