J Biol Chem, Vol. 273, Issue 49, 32870-32877, December 4, 1998
A Ribosomal Protein Is Required for Translational Regulation
of GCN4 mRNA
EVIDENCE FOR INVOLVEMENT OF THE RIBOSOME IN eIF2 RECYCLING
Peter P.
Mueller
§¶,
Patrick
Grueter
,
Alan G.
Hinnebusch§, and
Hans
Trachsel
From the
Institute of Biochemistry and Molecular
Biology, University of Berne, CH-3012 Berne, Switzerland, the
§ Laboratory of Eukaryotic Gene Regulation, NICHHD, National
Institutes of Health, Bethesda, Maryland 20892, and ¶ RDIF/GBF,
National Research Institute for Biotechnology, Mascheroder Weg 1, D-38124 Braunschweig, Germany
In amino acid-starved yeast cells, inhibition of
the guanine nucleotide exchange factor eIF2B by phosphorylated
translation initiation factor 2 results in increased translation of
GCN4 mRNA. We isolated a suppressor of a mutant eIF2B.
The suppressor prevents efficient GCN4 mRNA translation
due to inactivation of the small ribosomal subunit protein Rps31 and
results in low amounts of mutant 40 S ribosomal subunits. Deletion of
one of two genes encoding ribosomal protein Rps17 also reduces the
amounts of 40 S subunits but does not suppress eIF2B mutations or
prevent efficient GCN4 translation. Our findings show that
Rps31-deficient ribosomes are altered in a way that decreases the eIF2B
requirement and that the small ribosomal subunit mediates the effects
of low eIF2B activity on cell viability and translational regulation in
response to eIF2 phosphorylation.
Copyright © 1998 by The American Society for Biochemistry and Molecular Biology, Inc.