Recruitment and dissociation of nonhomologous end joining proteins at a DNA double-strand break in Saccharomyces cerevisiae.
نویسندگان
چکیده
Nonhomologous end joining (NHEJ) is an important DNA double-strand-break (DSB) repair pathway that requires three protein complexes in Saccharomyces cerevisiae: the Ku heterodimer (Yku70-Yku80), MRX (Mre11-Rad50-Xrs2), and DNA ligase IV (Dnl4-Lif1), as well as the ligase-associated protein Nej1. Here we use chromatin immunoprecipitation from yeast to dissect the recruitment and release of these protein complexes at HO-endonuclease-induced DSBs undergoing productive NHEJ. Results revealed that Ku and MRX assembled at a DSB independently and rapidly after DSB formation. Ligase IV appeared at the DSB later than Ku and MRX and in a strongly Ku-dependent manner. Ligase binding was extensive but slightly delayed in rad50 yeast. Ligase IV binding occurred independently of Nej1, but instead promoted loading of Nej1. Interestingly, dissociation of Ku and ligase from unrepaired DSBs depended on the presence of an intact MRX complex and ATP binding by Rad50, suggesting a possible role of MRX in terminating a NHEJ repair phase. This activity correlated with extended DSB resection, but limited degradation of DSB ends occurred even in MRX mutants with persistently bound Ku. These findings reveal the in vivo assembly of the NHEJ repair complex and shed light on the mechanisms controlling DSB repair pathway utilization.
منابع مشابه
Recruitment and dissociation of NHEJ proteins at a DNA double-strand break in Saccharomyces cerevisiae
متن کامل
Mismatch tolerance by DNA polymerase Pol4 in the course of nonhomologous end joining in Saccharomyces cerevisiae.
In yeast, the nonhomologous end joining pathway (NHEJ) mobilizes the DNA polymerase Pol4 to repair DNA double-strand breaks when gap filling is required prior to ligation. Using telomere-telomere fusions caused by loss of the telomeric protein Rap1 and double-strand break repair on transformed DNA as assays for NHEJ between fully uncohesive ends, we show that Pol4 is able to extend a 3'-end who...
متن کاملSaccharomyces cerevisiae Sae2- and Tel1-dependent single-strand DNA formation at DNA break promotes microhomology-mediated end joining.
Microhomology-mediated end joining (MMEJ) joins DNA ends via short stretches [5-20 nucleotides (nt)] of direct repeat sequences, yielding deletions of intervening sequences. Non-homologous end joining (NHEJ) and single-strand annealing (SSA) are other error prone processes that anneal single-stranded DNA (ssDNA) via a few bases (<5 nt) or extensive direct repeat homologies (>20 nt). Although th...
متن کاملSaccharomyces cerevisiae Sin3p facilitates DNA double-strand break repair.
There are two main pathways in eukaryotic cells for the repair of DNA double-strand breaks: homologous recombination and nonhomologous end joining. Because eukaryotic genomes are packaged in chromatin, these pathways are likely to require the modulation of chromatin structure. One way to achieve this is by the acetylation of lysine residues on the N-terminal tails of histones. Here we demonstra...
متن کاملInitiation of Ageing Process by Meiotic and Mitotic Recombination within the Ribosomal DNA Genes in Saccharomyces cerevisiae
In the budding yeast of Saccharomyces cerevisiae the tandem repeated of rDNA genes are located onchromosome XII, which is in the nucleolus. There are different types of proteins in the nucleoluskeleton,silencing proteins have got important role in nucleolus.It is shown that meiotic recombination between nonsister chromatids in the rDNA genes are stronglysuppressed, and s...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Genetics
دوره 178 3 شماره
صفحات -
تاریخ انتشار 2008