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The initial U3 snoRNA:pre‐rRNA base‐pairing interaction required for pre‐18S rRNA folding revealed by in vivo chemical probing
Author(s) -
Baserga Susan J.,
Dutca Laura M.,
Gallagher Jennifer E.G.
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.704.1
The synthesis of ribosomal subunits in the eukaryotic nucleolus is a conserved, essential process that results in cytoplasmic ribosomes with precisely processed and folded rRNAs assembled with ribosomal proteins. It has been proposed, but never directly demonstrated, that the U3 small nucleolar RNA (snoRNA) is a chaperone for pre‐18S rRNA folding. To test this, we used in vivo chemical probing with dimethyl sulfate to detect changes in pre‐rRNA structure upon genetic manipulation of the yeast, S. cerevisiae. Based on changes in nucleotide reactivity, we found that the U3 snoRNA is indeed required for folding of the pre‐18S rRNA. Furthermore, we detected a new essential base‐pairing interaction that is likely the initial anchor that recruits the U3 snoRNA to the pre‐rRNA, is a prerequisite for the subsequent interactions, and is required for the small subunit (SSU) processome formation. Thus, the U3 snoRNP, via base‐pairing, orchestrates the pre‐rRNA folding that results in the assembly of the small ribosomal subunit. This work was supported by NIH GM52581.