Previous Article | Next Article ![]()
Molecular and Cellular Biology, June 2000, p. 4006-4015, Vol. 20, No. 11
Section of Molecular Genetics and
Microbiology and Institute for Cellular and Molecular Biology,
University of Texas at Austin, Austin, Texas
78712-1095,1 and Life Sciences
Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee
37831-80802
Received 16 November 1999/Returned for modification 30 December
1999/Accepted 6 March 2000
The RAT1 gene of Saccharomyces cerevisiae
encodes a 5'
0270-7306/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Saccharomyces cerevisiae RAI1 (YGL246c)
Is Homologous to Human DOM3Z and Encodes a Protein That
Binds the Nuclear Exoribonuclease Rat1p
3' exoribonuclease which plays an essential role in
yeast RNA degradation and/or processing in the nucleus. We have cloned
a previously uncharacterized gene (YGL246c) that we refer to as
RAI1 (Rat1p interacting protein 1). RAI1 is
homologous to Caenorhabditis elegans DOM-3 and human
DOM3Z. Deletion of RAI1 confers a growth defect which can be complemented by an additional copy of RAT1 on
a centromeric vector or by directing Xrn1p, the cytoplasmic homolog of
Rat1p, to the nucleus through the addition of a nuclear targeting
sequence. Deletion of RAI1 is synthetically lethal with the
rat1-1ts mutation and shows genetic interaction
with a deletion of SKI2 but not XRN1. Polysome
analysis of an rai1 deletion mutant indicated a defect in
60S biogenesis which was nearly fully reversed by high-copy
RAT1. Northern blot analysis of rRNAs revealed that rai1 is required for normal 5.8S processing. In the absence
of RAI1, 5.8SL was the predominant form of 5.8S
and there was an accumulation of 3'-extended forms but not 5'-extended
species of 5.8S. In addition, a 27S pre-rRNA species accumulated in the rai1 mutant. Thus, deletion of RAI1 affects
both 5' and 3' processing reactions of 5.8S rRNA. Consistent with the
in vivo data suggesting that RAI1 enhances RAT1
function, purified Rai1p stabilized the in vitro exoribonuclease
activity of Rat1p.
*
Corresponding author. Mailing address: Section of
Molecular Genetics and Microbiology, University of Texas at Austin,
Austin, TX 78712-1095. Phone: (512) 475-6350. Fax: (512) 471-7088. E-mail: arlen{at}mail.utexas.edu.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|