Jeffrey N. Strathern

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Determining the effect of gene deletion is a fundamental approach to understanding gene function. Conventional genetic screens exhibit biases, and genes contributing to a phenotype are often missed. We systematically constructed a nearly complete collection of gene-deletion mutants (96% of annotated open reading frames, or ORFs) of the yeast Saccharomyces(More)
A double-stranded DNA cut has been observed in the mating type (MAT) locus of the yeast Saccharomyces cerevisiae in cultures undergoing homothallic cassette switching. Cutting is observed in exponentially growing cells of genotype HO HML alpha MAT alpha HMR alpha or HO HMLa MATa HMRa, which switch continuously, but not in a/alpha HO/HO diploid strains, in(More)
To study fidelity of RNA polymerase II (Pol II), we analyzed properties of the 6-azauracil-sensitive and TFIIS-dependent E1103G mutant of rbp1 (rpo21), the gene encoding the catalytic subunit of Pol II in Saccharomyces cerevisiae. Using an in vivo retrotransposition-based transcription fidelity assay, we observed that rpb1-E1103G causes a 3-fold increase in(More)
We present a genetic analysis of RAS1 and RAS2 of S. cerevisiae, two genes that are highly homologous to mammalian ras genes. By constructing in vitro ras genes disrupted by selectable genes and introducing these by gene replacement into the respective ras loci, we have determined that neither RAS1 nor RAS2 are by themselves essential genes. However, ras1 -(More)
We describe genetic and physical characterization of rearrangements of chromosome III which result in changes of cell type in S. cerevisiae. Two types of rearrangements were obtained as rare events which caused a change at the locus controlling cell type, MAT, associated with a recessive lethal mutation, in one case from MATalpha to MATa-lethal, and in the(More)
Homothallic Saccharomyces yeasts efficiently interconvert between two cell types, the mating types a and alpha. These interconversions have been proposed to occur by genetic rearrangement ("cassette" insertion) at the locus controlling cell type (the mating type locus). The pattern of switching from one cell type to the other during growth of a clone of(More)
Cells have high-fidelity polymerases whose task is to accurately replicate the genome, and low-fidelity polymerases with specialized functions. Although some of these low-fidelity polymerases are exceptional in their ability to replicate damaged DNA and restore the undamaged sequence, they are error prone on undamaged DNA. In fact, these error-prone(More)
The genes that control the a, alpha and a/alpha cell types in Saccharomyces are carried on transposable elements known as a and alpha cassettes which reside at three different chromosomal loci. Examination of the transcripts by R-looping and filter hybridization indicates that each cassette is capable of producing two divergent transcripts. Cassettes at the(More)
We have detected two site-specific endonucleases in strains of Saccharomyces cerevisiae. One endonuclease, which we call YZ endo, is present only in yeast strains that are undergoing mating-type interconversion. The site at which YZ endo cleaves corresponds to the in vivo double-strand break occurring at the mating-type locus in yeast undergoing mating-type(More)