Sj. Hong et al., ISOLATION OF AN EXTRAGENIC SUPPRESSOR OF THE RNA1-1 MUTATION IN SACCHAROMYCES-CEREVISIAE, MGG. Molecular & general genetics, 259(4), 1998, pp. 404-413
The small GTPase Ran is essential for nucleocytoplasmic transport of m
acromolecules. In the yeast Saccharomyces cerevisiae, Rna1p functions
as a Ran-GTPase activating protein (RanGAP1). Strains carrying the rna
1-1 mutation exhibit defects in nuclear transport and, as a consequenc
e, accumulate precursor tRNAs. We have isolated two recessive suppress
ors of the rna1-1 mutation. Further characterization of one of the sup
pressor mutations, srn10-1, reveals that the mutation (i) can not bypa
ss the need for Rna1p function and (ii) suppresses the accumulation of
unspliced pretRNA caused by ma1-1. The SRN10 gene is not essential fo
r cell viability and encodes an acidic protein (pI = 5.27) of 24.8 kDa
. Srn10p is located in the cytoplasm, as determined by indirect immuno
fluorescence microscopy. Two-hybrid analysis reveals that there is a p
hysical interaction between Srn10p and Rna1p in vive. Our results iden
tify a protein that interacts with the yeast RanGAP1.