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Ebp2p, yeast homologue of a human protein that interacts with Epstein–Barr virus Nuclear Antigen 1, is required for pre‐rRNA processing and ribosomal subunit assembly
Author(s) -
Tsujii Rota,
Miyoshi Keita,
Tsuno Akiko,
Matsui Yasushi,
Tohe Akio,
Miyakawa Tokichi,
Mizuta Keiko
Publication year - 2000
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1046/j.1365-2443.2000.00346.x
Subject(s) - biology , ribosome biogenesis , polysome , eukaryotic small ribosomal subunit , ribosomal rna , nucleolus , ribosomal protein , ribosome , protein subunit , eukaryotic ribosome , eukaryotic large ribosomal subunit , saccharomyces cerevisiae , microbiology and biotechnology , rna , biochemistry , gene , cytoplasm
Background A defect in the secretory pathway causes the transcriptional repression of both rRNA and ribosomal protein genes in Saccharomyces cerevisiae , suggesting a coupling of ribosome synthesis and plasma membrane synthesis. Rrs1p, an essential nuclear protein, is required for the secretory response. Results EBP2 , encoding the yeast homologue of a human protein that interacts with Epstein–Barr virus Nuclear Antigen 1, was cloned in a two‐hybrid screen using RRS1 as a bait. The rrs1‐1 mutation, which produces Rrs1p without the C‐terminal half and causes a defect in the secretory response, almost abolished the interaction with Ebp2p. Ebp2p is essential for growth and is mainly localized in the nucleolus. The effects of Ebp2p depletion on ribosome biogenesis is quite similar to that of Rrs1p depletion; in the Ebp2p‐depleted cells, the rate of pre‐rRNA processing is slower, and significantly less mature 25S rRNA is produced compared to those in wild‐type cells. The polysome pattern indicates that Ebp2p‐depletion causes a decrease of 80S monosomes and polysomes, an accumulation of 40S subunits, and the appearance of half‐mer polysomes. Conclusions Ebp2p is required for the maturation of 25S rRNA and 60S subunit assembly. Ebp2p may be one of the target proteins of Rrs1p for executing the signal to regulate ribosome biogenesis.