Abstract / Description of output
Box H/ACA small nucleolar ribonucleoprotein particles (snoRNPs) contain four essential proteins, Cbf5p, Gar1p, Nhp2p, and Nop10p, each of which, with the exception of Gar1p, is required for box H/ACA snoRNA accumulation. Database searches identified a novel essential protein, which we termed Naf1p, with a region of homology to the RNA-binding domain of Gar1p and other features in common with hnRNP-like proteins. Naf1p is localized to the nucleus and is not a stable component of the H/ACA snoRNPs, but it is required for the accumulation of all box H/ACA snoRNAs. This requirement is not at the level of snoRNA transcription initiation or termination. Naf1p shows in vitro RNA-binding activity and also binds directly to Cbf5p and Nhp2p. Naf1p was shown to bind to the CTD in vivo in a two-hybrid assay, and the phosphorylated CTD, but not the nonphosphorylated CTD, was shown to precipitate tagged Naf1p from a cell lysate. We propose that Naf1p is recruited to the CTD of RNA polymerase 11 and binds to nascent box H/ACA snoRNAs promoting snoRNP assembly.
Original language | English |
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Pages (from-to) | 1502-1514 |
Number of pages | 13 |
Journal | RNA |
Volume | 8 |
Issue number | 12 |
Publication status | Published - Dec 2002 |
Keywords / Materials (for Non-textual outputs)
- ACA snoRNPs
- box H
- snoRNP assembly