Screening and identification of yeast sequences that cause growth inhibition when overexpressed |
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Authors: | R Akada J Yamamoto and I Yamashita |
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Institution: | (1) Center for Gene Science, Hiroshima University, Higashi-Hiroshima 739, Japan, JP |
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Abstract: | To isolate genes that negatively regulate cell growth, we constructed a galactose-inducible expression library with partially
digested Saccharomyces cerevisiae genomic DNA fragments inserted downstream of the GAL10 promoter. In all, 240 000 yeast transformants were screened for lethality on galactose medium. From 17 such transformants
identified, 16 nonoverlapping DNA sequences were obtained. Restriction mapping and determination of DNA sequences adjacent
to the GAL10 promoter indicated that the inserts encoded part or all of the URA2, RBP1, TPK3, SAC7, BOI1, and BNI1 genes, and also open reading frames (ORFs) from chromosomes IV, V, IX, XI, and XIII. Some of the identified sequences lacked
the amino-terminal sequences of the ORFs, suggesting that truncated forms of the proteins might be necessary for growth inhibition.
The sequence of the pGA108 insert was highly homologous to the telomeric X-element and contained an ARS consensus sequence, suggesting a possible growth inhibitory effect of an RNA molecule. Overexpression of the BNI1ΔN and BOI1ΔN genes, which lacked amino-terminal sequences, was associated with phenotypes similar to those of mutants defective in bud
formation. Overexpression of the GIN4 and GIN12 sequences induced elongated buds and a G2/M arrest-like phenotype, respectively.
The phenotypes induced by the overexpression of our cloned sequences could result from either a dominant-positive or a dominant-negative
effect and, unexpectedly, in one case from an effect of an RNA.
Received: 3 June 1996 / Accepted: 1 October 1996 |
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Keywords: | Saccharomycescerevisiae Overexpression Growth inhibition Library screening |
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