A role for Saccharomyces cerevisiae histone H2A in DNA repair

Nature ◽  
2000 ◽  
Vol 408 (6815) ◽  
pp. 1001-1004 ◽  
Author(s):  
Jessica A. Downs ◽  
Noel F. Lowndes ◽  
Stephen P. Jackson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Repair ◽  
Histone H2a

scholarly journals Saccharomyces cerevisiae Histone H2A Ser122 Facilitates DNA Repair

Genetics ◽  
2005 ◽  
Vol 170 (2) ◽  
pp. 543-553 ◽  
Author(s):  
Anne C. Harvey ◽  
Stephen P. Jackson ◽  
Jessica A. Downs
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Repair ◽  
Histone H2a

scholarly journals Cis-Elements Governing Trinucleotide Repeat Instability in Saccharomyces cerevisiae

Genetics ◽  
2001 ◽  
Vol 157 (4) ◽  
pp. 1569-1579 ◽  
Author(s):  
Michael L Rolfsmeier ◽  
Michael J Dixon ◽  
Luis Pessoa-Brandão ◽  
Richard Pelletier ◽  
Juan José Miret ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Repair ◽  
Sequence Analysis ◽  
Trinucleotide Repeat ◽  
Model Systems ◽  
Sequence Specificity ◽  
Cis Elements ◽  
Frequent Mutations ◽  
Yeast Genetic ◽  
Molecular Nature

Abstract Trinucleotide repeat (TNR) instability in humans is governed by unique cis-elements. One element is a threshold, or minimal repeat length, conferring frequent mutations. Since thresholds have not been directly demonstrated in model systems, their molecular nature remains uncertain. Another element is sequence specificity. Unstable TNR sequences are almost always CNG, whose hairpin-forming ability is thought to promote instability by inhibiting DNA repair. To understand these cis-elements further, TNR expansions and contractions were monitored by yeast genetic assays. A threshold of ∼15–17 repeats was observed for CTG expansions and contractions, indicating that thresholds function in organisms besides humans. Mutants lacking the flap endonuclease Rad27p showed little change in the expansion threshold, suggesting that this element is not altered by the presence or absence of flap processing. CNG or GNC sequences yielded frequent mutations, whereas A-T rich sequences were substantially more stable. This sequence analysis further supports a hairpin-mediated mechanism of TNR instability. Expansions and contractions occurred at comparable rates for CTG tract lengths between 15 and 25 repeats, indicating that expansions can comprise a significant fraction of mutations in yeast. These results indicate that several unique cis-elements of human TNR instability are functional in yeast.

scholarly journals The SRS2 suppressor of rad6 mutations of Saccharomyces cerevisiae acts by channeling DNA lesions into the RAD52 DNA repair pathway.

Genetics ◽  
1990 ◽  
Vol 124 (4) ◽  
pp. 817-831 ◽  
Author(s):  
R H Schiestl ◽  
S Prakash ◽  
L Prakash
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Repair ◽  
Gamma Ray ◽  
Dna Lesions ◽  
Recombinational Repair ◽  
Repair Pathway ◽  
Uv Mutagenesis ◽  
Uv Sensitivity ◽  
Suppressor Mutations ◽  
Induced Mutagenesis

Abstract rad6 mutants of Saccharomyces cerevisiae are defective in the repair of damaged DNA, DNA damage induced mutagenesis, and sporulation. In order to identify genes that can substitute for RAD6 function, we have isolated genomic suppressors of the UV sensitivity of rad6 deletion (rad6 delta) mutations and show that they also suppress the gamma-ray sensitivity but not the UV mutagenesis or sporulation defects of rad6. The suppressors show semidominance for suppression of UV sensitivity and dominance for suppression of gamma-ray sensitivity. The six suppressor mutations we isolated are all alleles of the same locus and are also allelic to a previously described suppressor of the rad6-1 nonsense mutation, SRS2. We show that suppression of rad6 delta is dependent on the RAD52 recombinational repair pathway since suppression is not observed in the rad6 delta SRS2 strain containing an additional mutation in either the RAD51, RAD52, RAD54, RAD55 or RAD57 genes. Possible mechanisms by which SRS2 may channel unrepaired DNA lesions into the RAD52 DNA repair pathway are discussed.

scholarly journals The Large Subunit of Replication Factor C (Rfclp/Cdc44p) Is Required for DNA Replication and DNA Repair in Saccharomyces cerevisiae

Genetics ◽  
1996 ◽  
Vol 142 (1) ◽  
pp. 65-78 ◽  
Author(s):  
Michael A McAlear ◽  
K Michelle Tuffo ◽  
Connie Holm
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Repair ◽  
Dna Replication ◽  
Uv Radiation ◽  
Large Subunit ◽  
Restrictive Temperature ◽  
Replication Factor C ◽  
Replication Factor ◽  
Factor C

We used genetic and biochemical techniques to characterize the phenotypes associated with mutations affecting the large subunit of replication factor C (Cdc44p or Rfc1p) in Saccharomyces cerevisiae. We demonstrate that Cdc44p is required for both DNA replication and DNA repair in vivo. Cold-sensitive cdc44 mutants experience a delay in traversing S phase at the restrictive temperature following alpha factor arrest; although mutant cells eventually accumulate with a G2/M DNA content, they undergo a cell cycle arrest and initiate neither mitosis nor a new round of DNA synthesis. cdc44 mutants also exhibit an elevated level of spontaneous mutation, and they are sensitive both to the DNA damaging agent methylmethane sulfonate and to exposure to UV radiation. After exposure to UV radiation, cdc44 mutants at the restrictive temperature contain higher levels of single-stranded DNA breaks than do wild-type cells. This observation is consistent with the hypothesis that Cdc44p is involved in repairing gaps in the DNA after the excision of damaged bases. Thus, Cdc44p plays an important role in both DNA replication and DNA repair in vivo.

scholarly journals Histone variant H2A.B-H2B dimers are spontaneously exchanged with canonical H2A-H2B in the nucleosome

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Rina Hirano ◽  
Yasuhiro Arimura ◽  
Tomoya Kujirai ◽  
Mikihiro Shibata ◽  
Aya Okuda ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Dna Repair ◽  
High Speed ◽  
Histone Chaperones ◽  
Histone H2a ◽  
Force Microscopy ◽  
Atomic Force ◽  
Open Conformation ◽  
Replication Sites ◽  
Histone Exchange

AbstractH2A.B is an evolutionarily distant histone H2A variant that accumulates on DNA repair sites, DNA replication sites, and actively transcribing regions in genomes. In cells, H2A.B exchanges rapidly in chromatin, but the mechanism has remained enigmatic. In the present study, we found that the H2A.B-H2B dimer incorporated within the nucleosome exchanges with the canonical H2A-H2B dimer without assistance from additional factors, such as histone chaperones and nucleosome remodelers. High-speed atomic force microscopy revealed that the H2A.B nucleosome, but not the canonical H2A nucleosome, transiently forms an intermediate “open conformation”, in which two H2A.B-H2B dimers may be detached from the H3-H4 tetramer and bind to the DNA regions near the entry/exit sites. Mutational analyses revealed that the H2A.B C-terminal region is responsible for the adoption of the open conformation and the H2A.B-H2B exchange in the nucleosome. These findings provide mechanistic insights into the histone exchange of the H2A.B nucleosome.

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