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Loc1p is required for efficient assembly and nuclear export of the 60S ribosomal subunit. Mol Genet Genomics 2006 Oct;276(4):369-77



Pubmed ID




Scopus ID

2-s2.0-33748319405 (requires institutional sign-in at Scopus site)   21 Citations


Loc1p is an exclusively nuclear dsRNA-binding protein that affects the asymmetric sorting of ASH1 mRNA to daughter cells in Saccharomyces cerevisiae. In addition to the role in cytoplasmic RNA localization, Loc1p is a constituent of pre-60S ribosomes. Cells devoid of Loc1p display a defect in the synthesis of 60S ribosomal subunits, resulting in "half-mer" polyribosomes. Previously, we reported that Loc1p is located throughout the entire nucleus; however, upon closer inspection we discovered that Loc1p is enriched in the nucleolus consistent with a role in 60S ribosome biogenesis. Given that Loc1p is an RNA-binding protein and presumably functions in the assembly of 60S ribosomal subunits, we investigated if Loc1p has a role in rRNA processing and nuclear export of 60S subunits. Analysis of pre-rRNA processing revealed that loc1Delta cells exhibit gross defects in 25S rRNA synthesis, specifically a delay in processing at sites A0, A1 and A2 in 35S pre-rRNA. Furthermore, loc1Delta cells exhibit nuclear export defects for 60S ribosomal subunits, again, consistent with a role for Loc1p in the assembly of 60S ribosomal subunits. It is attractive to hypothesize that the two phenotypes associated with loc1Delta cells, namely altered ASH1 mRNA localization and ribosome biogenesis, are not mutually exclusive, but that ribosome biogenesis directly impacts mRNA localization.

Author List

Urbinati CR, Gonsalvez GB, Aris JP, Long RM


Roy M. Long PhD Assistant Dean, Associate Professor in the Medical School Regional Campuses department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Active Transport, Cell Nucleus
Base Sequence
DNA, Fungal
DNA-Binding Proteins
Nuclear Proteins
RNA Precursors
RNA Processing, Post-Transcriptional
RNA, Fungal
RNA-Binding Proteins
Repressor Proteins
Saccharomyces cerevisiae
Saccharomyces cerevisiae Proteins