The Detection and Measurement of Base and Nucleotide Excision Repair in Cell-Free Extracts of the Yeast Saccharomyces cerevisiae

Methods ◽  
1995 ◽  
Vol 7 (2) ◽  
pp. 177-186 ◽  
Author(s):  
Zhigang Wang ◽  
Xiaohua Wu ◽  
Errol C. Friedberg

Nucleotide excision repair (ner) in eukaryotes is a biochemically complex process involving multiple gene products. The budding yeast Saccharomyces cerevisiae is an informative model for this process. Multiple genes and in some cases gene products that are indispensable for ner have been isolated from this organism. Homologues of many of these yeast genes are structurally and functionally conserved in higher organisms, including humans. The yeast Rad1/Rad10 heterodimeric protein complex is an endonuclease that is believed to participate in damage-specific incision of DNA during ner . This endonuclease is also required for specialized types of recombination. The products of the RAD3, SSL2(RAD25) SSL1 and TFB1 genes have dual roles in ner and in RNA polymerase II-dependent basal transcription.


Author(s):  
Errol C. Friedberg ◽  
Reinhard Fleer ◽  
Louie Naumovski ◽  
Charles M. Nicolet ◽  
Gordon W. Robinson ◽  
...  

1995 ◽  
Vol 15 (4) ◽  
pp. 2245-2251 ◽  
Author(s):  
E L Ivanov ◽  
J E Haber

HO endonuclease-induced double-strand breaks (DSBs) in the yeast Saccharomyces cerevisiae can be repaired by the process of gap repair or, alternatively, by single-strand annealing if the site of the break is flanked by directly repeated homologous sequences. We have shown previously (J. Fishman-Lobell and J. E. Haber, Science 258:480-484, 1992) that during the repair of an HO-induced DSB, the excision repair gene RAD1 is needed to remove regions of nonhomology from the DSB ends. In this report, we present evidence that among nine genes involved in nucleotide excision repair, only RAD1 and RAD10 are required for removal of nonhomologous sequences from the DSB ends. rad1 delta and rad10 delta mutants displayed a 20-fold reduction in the ability to execute both gap repair and single-strand annealing pathways of HO-induced recombination. Mutations in RAD2, RAD3, and RAD14 reduced HO-induced recombination by about twofold. We also show that RAD7 and RAD16, which are required to remove UV photodamage from the silent HML, locus, are not required for MAT switching with HML or HMR as a donor. Our results provide a molecular basis for understanding the role of yeast nucleotide excision repair gene and their human homologs in DSB-induced recombination and repair.


1997 ◽  
Vol 17 (2) ◽  
pp. 635-643 ◽  
Author(s):  
Z Wang ◽  
S Wei ◽  
S H Reed ◽  
X Wu ◽  
J Q Svejstrup ◽  
...  

Nucleotide excision repair (NER) is a biochemical process required for the repair of many different types of DNA lesions. In the yeast Saccharomyces cerevisiae, the RAD7, RAD16, and RAD23 genes have been specifically implicated in NER of certain transcriptionally repressed loci and in the nontranscribed strand of transcriptionally active genes. We have used a cell-free system to study the roles of the Rad7, Rad16, and Rad23 proteins in NER. Transcription-independent NER of a plasmid substrate was defective in rad7, rad16, and rad23 mutant extracts. Complementation studies with a previously purified NER protein complex (nucleotide excision repairosome) indicate that Rad23 is a component of the repairosome, whereas Rad7 and Rad16 proteins were not found in this complex. Complementation studies with rad4, rad7, rad16, and rad23 mutant extracts suggest physical interactions among these proteins. This conclusion was confirmed by experiments using the yeast two-hybrid assay, which demonstrated the following pairwise interactions: Rad4 with Rad23, Rad4 with Rad7, and Rad7 with Rad16. Additionally, interaction between the Rad7 and Rad16 proteins was demonstrated in vitro. Our results show that Rad7, Rad16, and Rad23 are required for transcription-independent NER in vitro. This process may involve a unique protein complex which is distinct from the repairosome and which contains at least the Rad4, Rad7, and Rad16 proteins.


Genetics ◽  
2000 ◽  
Vol 154 (1) ◽  
pp. 133-146 ◽  
Author(s):  
Ainsley Nicholson ◽  
Miyono Hendrix ◽  
Sue Jinks-Robertson ◽  
Gray F Crouse

Abstract The Saccharomyces cerevisiae homologs of the bacterial mismatch repair proteins MutS and MutL correct replication errors and prevent recombination between homeologous (nonidentical) sequences. Previously, we demonstrated that Msh2p, Msh3p, and Pms1p regulate recombination between 91% identical inverted repeats, and here use the same substrates to show that Mlh1p and Msh6p have important antirecombination roles. In addition, substrates containing defined types of mismatches (base-base mismatches; 1-, 4-, or 12-nt insertion/deletion loops; or 18-nt palindromes) were used to examine recognition of these mismatches in mitotic recombination intermediates. Msh2p was required for recognition of all types of mismatches, whereas Msh6p recognized only base-base mismatches and 1-nt insertion/deletion loops. Msh3p was involved in recognition of the palindrome and all loops, but also had an unexpected antirecombination role when the potential heteroduplex contained only base-base mismatches. In contrast to their similar antimutator roles, Pms1p consistently inhibited recombination to a lesser degree than did Msh2p. In addition to the yeast MutS and MutL homologs, the exonuclease Exo1p and the nucleotide excision repair proteins Rad1p and Rad10p were found to have roles in inhibiting recombination between mismatched substrates.


1989 ◽  
Vol 9 (11) ◽  
pp. 4777-4788 ◽  
Author(s):  
M Baer ◽  
G B Sancar

DNA photolyases catalyze the light-dependent repair of pyrimidine dimers in DNA. The results of nucleotide sequence analysis and spectroscopic studies demonstrated that photolyases from Saccharomyces cerevisiae and Escherichia coli share 37% amino acid sequence homology and contain identical chromophores. Do the similarities between these two enzymes extend to their interactions with DNA containing pyrimidine dimers, or does the organization of DNA into nucleosomes in S. cerevisiae necessitate alternative or additional recognition determinants? To answer this question, we used chemical and enzymatic techniques to identify the contacts made on DNA by S. cerevisiae photolyase when it is bound to a pyrimidine dimer and compared these contacts with those made by E. coli photolyase and by a truncated derivative of the yeast enzyme when bound to the same substrate. We found evidence for a common set of interactions between the photolyases and specific phosphates in the backbones of both strands as well as for interactions with bases in both the major and minor grooves of dimer-containing DNA. Superimposed on this common pattern were significant differences in the contributions of specific contacts to the overall binding energy, in the interactions of the enzymes with groups on the complementary strand, and in the extent to which other DNA-binding proteins were excluded from the region around the dimer. These results provide strong evidence both for a conserved dimer-binding motif and for the evolution of new interactions that permit photolyases to also act as accessory proteins in nucleotide excision repair. The locations of the specific contacts made by the yeast enzyme indicate that the mechanism of nucleotide excision repair in this organism involves incision(s) at a distance from the pyrimidine dimer.


2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Bernadette Connors ◽  
Lauren Rochelle ◽  
Asela Roberts ◽  
Graham Howard

Regulation of DNA repair can be achieved through ubiquitin-mediated degradation of transiently induced proteins. In Saccharomyces cerevisiae, Rad4 is involved in damage recognition during nucleotide excision repair (NER) and, in conjunction with Rad23, recruits other proteins to the site of damage. We identified a synthetic interaction upon UV exposure between Rad4 and Cdc20, a protein that modulates the activity of the anaphase promoting complex (APC/C), a multisubunit E3 ubiquitin ligase complex. The moderately UV sensitive Δrad4 strain became highly sensitive when cdc20-1 was present, and was rescued by overexpression of CDC20. The double mutant is also deficient in elicting RNR3-lacZ transcription upon exposure to UV irradiation or 4-NQO compared with the Δrad4 single mutant. We demonstrate that the Δrad4/cdc20-1 double mutant is defective in double strand break repair by way of a plasmid end-joining assay, indicating that Rad4 acts to ensure that damaged DNA is repaired via a Cdc20-mediated mechanism. This study is the first to present evidence that Cdc20 may play a role in the degradation of proteins involved in nucleotide excision repair.


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