A role for RAD54B in homologous recombination in human cells

Miyagawa, Kiyoshi; Tsuruga, Takanori; Kinomura, Aiko; Usui, Kiyomi; Katsura, Mari; Tashiro, Satoshi; Mishima, Hiromu K.; Tanaka, Kozo

doi:10.1093/emboj/21.1.175

Cited by 77 publications

(87 citation statements)

References 31 publications

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“…Although previous studies suggest that Rad54B plays roles in the HR and DNA repair processes 6,7 , we found a completely novel function of Rad54B; Rad54B suppressed the p53 levels and functions in the steady state independently of the activity of ATM (Fig. 1g,h and Supplementary Fig.…”

Section: Rad54b Suppresses the P53 Levels Independently Of Atmmentioning

confidence: 56%

“…All media were supplemented with 10% fetal bovine serum. The RAD54B KO HCT116 cells were previously described 6 . MG132 (C2211) and cycloheximide (C4859) were obtained from Sigma-Aldrich.…”

Section: Methodsmentioning

confidence: 99%

“…Rad54B and Rad54 belong to a subfamily of doublestranded DNA-dependent ATPases referred to as the SWI2/SNF2 family, which is characterized by conserved helicase-like sequence motifs 5 . Although previous studies suggested that Rad54B plays roles in the HR and DNA repair processes [6][7][8][9] , biochemical analysis has shown that Rad54B is a less active DNA-dependent ATPase than Rad54 (ref. 10).…”

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confidence: 99%

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Rad54B serves as a scaffold in the DNA damage response that limits checkpoint strength

et al. 2014

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The strength of the DNA damage checkpoint critically influences cell fate, yet the mechanisms behind the fine tuning of checkpoint strength during the DNA damage response (DDR) are poorly understood. Here we show that Rad54B-a SNF2 helicase-like DNA-repair protein-limits the strength of both the G1/S and G2/M checkpoints. We find that Rad54B functions as a scaffold for p53 degradation via its direct interaction with the MDM2-MDMX ubiquitin-ligase complex. During the early phases of the DDR, Rad54B is upregulated, thereby maintaining low checkpoint strength and facilitating cell cycle progression. Once the p53-mediated checkpoint is established, Rad54B is downregulated, and high checkpoint strength is maintained. Constitutive upregulation of Rad54B activity, which is frequently observed in tumours, promotes genomic instability because of checkpoint override. Thus, the scaffolding function of Rad54B dynamically regulates the maintenance of genome integrity by limiting checkpoint strength.

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Section: Rad54b Suppresses the P53 Levels Independently Of Atmmentioning

confidence: 56%

“…All media were supplemented with 10% fetal bovine serum. The RAD54B KO HCT116 cells were previously described 6 . MG132 (C2211) and cycloheximide (C4859) were obtained from Sigma-Aldrich.…”

Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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Rad54B serves as a scaffold in the DNA damage response that limits checkpoint strength

et al. 2014

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“…AtRAD54 is a putative homolog of SNF2/RAD54 subfamily that is involved in both DNA repair and transcriptional regulation. (65) AtRAD54 is activated in synthetic Arabidopsis auto-and allotetraploids but not in diploid parents and natural allotetraploids (A. suecica), (43) suggesting a role of DNA recombination and repair in the maintenance of genomic stability during early stages of polyploidy formation. Types of genomic and gene expression changes documented in the polyploids.…”

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confidence: 99%

Mechanisms of genomic rearrangements and gene expression changes in plant polyploids

2006

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SummaryPolyploidy is produced by multiplication of a single genome (autopolyploid) or combination of two or more divergent genomes (allopolyploid). The available data obtained from the study of synthetic (newly created or human-made) plant allopolyploids have documented dynamic and stochastic changes in genomic organization and gene expression, including sequence elimination, inter-chromosomal exchanges, cytosine methylation, gene repression, novel activation, genetic dominance, subfunctionalization and transposon activation. The underlying mechanisms for these alterations are poorly understood. To promote a better understanding of genomic and gene expression changes in polyploidy, we briefly review origins and forms of polyploidy and summarize what has been learned from genome-wide gene expression analyses in newly synthesized autoand allopolyploids. We show transcriptome divergence between the progenitors and in the newly formed allopolyploids. We propose models for transcriptional regulation, chromatin modification and RNA-mediated pathways in establishing locus-specific expression of orthologous and homoeologous genes during allopolyploid formation and evolution. Polyploidy and its formsPolyploidy occurs throughout the evolutionary history of all eukaryotes, (1,2) predominately in flowering plants (3,4) including many important agricultural crops. (5) Compared to plants, polyploidy occurs rarely in animals, but clearly exists in some invertebrates (e.g. insects) and vertebrates (e.g. fish, amphibians and reptiles). (4,6) The relative paucity of polyploidy in animals is attributed to the delicate schemes of sex determination and animal development, which are disrupted by polyploidization. (7,8) Therefore, polyploid animals rarely exist. (9) Moreover, aneuploid and polyploid cells in animals and human are often associated with malignant cell proliferation or carcinogenesis. (10) However, endopolyploidy (somatic polyploid cells within a diploid individual) appears to be a physiological response to developmental changes in plants and some animals, (11,12) indicating plasticity of plant and animal genomes. In the post-sequencing era, polyploidy is proving to be a fascinating and challenging field of plant biology, stimulating many research advances and insightful reviews. (2,13 -24) Here we attempt to update the views using genomic-scale results and provide new mechanistic insights.Historically, Winkler (1916) introduced the term polyploidy, (25) and Winge (1917) called attention to the general importance of polyploidy in the evolution of angiosperms. (26) At that time, research in polyploidy was somewhat limited by the plant and animal materials that were available in nature. In 1937, Blakeslee and Avery induced polyploidy in plants using colchicine, a chemical inhibitor of mitotic cell divisions. (27) The technique has been successfully used to induce chromosome doubling in meristemic cells of diploids and interspecific hybrids. Doubling a single 'diploid' genome results in an autotetraploid, while doubling c...

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“…Inactivation of the mouse RAD54 gene causes a marked sensitivity to DNA-damaging agents in embryonic stem cells, but somatic cells deleted for Rad54 show only a slight increase in radiosensitivity (43)(44)(45)(46). Inactivation of the RAD54B gene in a colon cancer cell line resulted in a severe reduction of targeted integration frequency, whereas sensitivity to DNA-damaging agents and sister chromatid exchange was not significantly affected (47). hRad54 protein colocalizes with hRad51 and BRCA1 in the nucleus (48,49), and significant colocalization of Rad54B with hRad51 and BRCA1 has also been observed (50).…”

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confidence: 99%

Effects of Tumor-associated Mutations on Rad54 Functions

Smirnova

Komen

Sung

et al. 2004

Journal of Biological Chemistry

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Yeast RAD54 gene, a member of the RAD52 epistasis group, plays an important role in homologous recombination and DNA double strand break repair. Rad54 belongs to the Snf2/Swi2 protein family, and it possesses a robust DNA-dependent ATPase activity, uses free energy from ATP hydrolysis to supercoil DNA, and cooperates with the Rad51 recombinase in DNA joint formation. There are two RAD54-homologous genes in human cells, hRAD54 and RAD54B. Mutations in these human genes have been found in tumors. These tumor-associated mutations map to conserved regions of the hRad54 and hRad54B proteins. Here we introduced the equivalent mutations into the Saccharomyces cerevisiae RAD54 gene in an effort to examine the functional consequences of these gene changes. One mutant, rad54 G484R, showed sensitivity to DNA-damaging agents and reduced homologous recombination rates, indicating a loss of function. Even though the purified rad54 G484R mutant protein retained the ability to bind DNA and interact with Rad51, it was nearly devoid of ATPase activity and was similarly defective in DNA supercoiling and D-loop formation. Two other mutants, rad54 N616S and rad54 D442Y, were not sensitive to genotoxic agents and behaved like the wild type allele in homologous recombination assays. Consistent with the mild phenotype associated with the rad54 N616S allele, its encoded protein was similar to wild type Rad54 protein in biochemical attributes. Because dysfunctional homologous recombination gives rise to genome instability, our results are consistent with the premise that tumor-associated mutations in hRad54 and Rad54B could contribute to the tumor phenotype or enhance the genome instability seen in tumor cells.In Saccharomyces cerevisiae, homologous recombination (HR) 1 represents an important means for the repair of DNA double strand breaks and other types of DNA damage and also for restarting stalled replication forks (1-5). HR depends on the use of a homologous DNA molecule as a template to eliminate double strand breaks and other lesions mostly with high fidelity. Impaired HR results in genetic instability and sensitivity to genotoxic agents (6) and can lead to cancer in humans (7). Double strand break repair by HR is dependent on genes of the RAD52 epistasis group, RAD50, RAD51, RAD54, RAD55, RAD57, RAD59, RDH54/TID1, MRE11, and XRS2, in which structure and function have been highly conserved (6). Before repair can occur, the ends of double strand breaks are processed by nucleolytic resection of the 5Ј ends of the breaks to yield ssDNA, which is then bound by Rad51 to form a helical nucleoprotein filament often referred to as the presynaptic filament. Nucleation of Rad51 onto the ssDNA is facilitated by recombination mediators, including Rad52, the Rad55-Rad57 complex, and Rad54 (6,8). Once assembled, the presynaptic filament mediates a search for homology in the homologous dsDNA partner and forms a DNA joint molecule (called D-loop) with the latter. The length of the nascent DNA joint molecule is extended by DNA branch migration (9...

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A role for RAD54B in homologous recombination in human cells

Cited by 77 publications

References 31 publications

Rad54B serves as a scaffold in the DNA damage response that limits checkpoint strength

Rad54B serves as a scaffold in the DNA damage response that limits checkpoint strength

Mechanisms of genomic rearrangements and gene expression changes in plant polyploids

Effects of Tumor-associated Mutations on Rad54 Functions

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