Cordycepin-hypersensitive growth links elevated polyphosphate levels to inhibition of poly(A) polymerase in Saccharomyces cerevisiae
To identify genes involved in poly(A) metabolism, we screened the yeast gene deletion collection for growth defects in the presence of cordycepin (3'-deoxyadenosine), a precursor to the RNA chain terminating ATP analog cordycepin triphosphate. Δpho80 and Δpho85 strains, which have a constitutiv...
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Published in | Nucleic acids research Vol. 36; no. 2; pp. 353 - 363 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
England
Oxford University Press
01.02.2008
Oxford Publishing Limited (England) |
Subjects | |
Online Access | Get full text |
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Summary: | To identify genes involved in poly(A) metabolism, we screened the yeast gene deletion collection for growth defects in the presence of cordycepin (3'-deoxyadenosine), a precursor to the RNA chain terminating ATP analog cordycepin triphosphate. Δpho80 and Δpho85 strains, which have a constitutively active phosphate-response pathway, were identified as cordycepin hypersensitive. We show that inorganic polyphosphate (poly P) accumulated in these strains and that poly P is a potent inhibitor of poly(A) polymerase activity in vitro. Binding analyses of poly P and yeast Pap1p revealed an interaction with a kD in the low nanomolar range. Poly P also bound mammalian poly(A) polymerase, however, with a 10-fold higher kD compared to yeast Pap1p. Genetic tests with double mutants of Δpho80 and other genes involved in phosphate homeostasis and poly P accumulation suggest that poly P contributed to cordycepin hypersensitivity. Synergistic inhibition of mRNA synthesis through poly P-mediated inhibition of Pap1p and through cordycepin-mediated RNA chain termination may thus account for hypersensitive growth of Δpho80 and Δpho85 strains in the presence of the chain terminator. Consistent with this, a mutation in the 3'-end formation component rna14 was synthetic lethal in combination with Δpho80. Based on these observations, we suggest that binding of poly P to poly(A) polymerase negatively regulates its activity. |
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Bibliography: | The authors wish it to be known that, in their opinion, the first two authors should be regarded as joint First Authors. ark:/67375/HXZ-ZKGR36RS-3 ArticleID:gkm990 istex:530039AAEFCBE8DBD03DF3965C04EC117D1C43E7 |
ISSN: | 0305-1048 1362-4962 |
DOI: | 10.1093/nar/gkm990 |