The breast and ovarian cancer susceptibility protein BRCA1 is evolutionarily conserved and functions in DNA double-strand break (DSB) repair through homologous recombination, but its role in meiosis is poorly understood. By using genetic analysis, we investigated the role of the Caenorhabditis elegans BRCA1 orthologue (brc-1) during meiotic prophase. The null mutant in the brc-1 gene is viable, fertile and shows the wild-type complement of six bivalents in most diakinetic nuclei, which is indicative of successful crossover recombination. However, brc-1 mutants show an abnormal increase in apoptosis and RAD-51 foci at pachytene that are abolished by loss of spo-11 function, suggesting a defect in meiosis rather than during premeiotic DNA replication. In genetic backgrounds in which chiasma formation is abrogated, such as him-14/MSH4 and syp-2, loss of brc-1 leads to chromosome fragmentation suggesting that brc-1 is dispensable for crossing over but essential for DSB repair through inter-sister recombination.
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http://dx.doi.org/10.1038/sj.embor.7401167 | DOI Listing |
Nucleic Acids Res
January 2025
Department of Convergent Bioscience and Informatics, College of Bioscience and Biotechnology, Chungnam National University, 99, Daehak-ro, Yuseong-gu, Daejeon 34134, Republic of Korea.
Large genetic variants can be generated via homologous recombination (HR), such as polymerase theta-mediated end joining (TMEJ) or single-strand annealing (SSA). Given that these HR-based mechanisms leave specific genomic signatures, we developed GDBr, a genomic signature interpretation tool for DNA double-strand break repair mechanisms using high-quality genome assemblies. We applied GDBr to a draft human pangenome reference.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Kansai Institute for Photon Science, National Institutes for Quantum Science and Technology (QST), 8-1-7 Umemidai, Kizugawa-shi, Kyoto 619-0215, Japan.
Ionizing radiation induces various types of DNA damage, and the reparability and lethal effects of DNA damage differ depending on its spatial density. Elucidating the structure of radiation-induced clustered DNA damage and its repair processes will enhance our understanding of the lethal impact of ionizing radiation and advance progress toward precise therapeutics. Previously, we developed a method to directly visualize DNA damage using atomic force microscopy (AFM) and classified clustered DNA damage into simple base damage clusters (BDCs), complex BDCs and complex double-strand breaks (DSBs).
View Article and Find Full Text PDFInt J Mol Sci
January 2025
State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences, Beijing 100071, China.
RAD52 plays crucial roles in several aspects of mammalian cells, including DNA double-strand breaks repair, viral infection, cancer development, and antibody class switching. To comprehensively elucidate the role of RAD52 in maintaining genome stability and uncover additional functions of RAD52 in mammals, we performed the transcriptomics and proteomics analysis of the liver of knockout mice. Transcriptomics analysis reveals overexpression of mitochondrial genes in the liver of knockout (RAD52KO) mice.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA.
Prime editing (PE) is a CRISPR-based tool for genome engineering that can be applied to generate human induced pluripotent stem cell (hiPSC)-based disease models. PE technology safely introduces point mutations, small insertions, and deletions (indels) into the genome. It uses a Cas9-nickase (nCas9) fused to a reverse transcriptase (RT) as an editor and a PE guide RNA (pegRNA), which introduces the desired edit with great precision without creating double-strand breaks (DSBs).
View Article and Find Full Text PDFCytokine Growth Factor Rev
January 2025
Center for Precision Medicine, China Medical University Hospital, China Medical University, Taichung, Taiwan; Department of Pathology, College of Medicine, China Medical University, Taichung, Taiwan. Electronic address:
Receptor tyrosine kinases (RTKs) are membrane sensors that monitor alterations in the extracellular milieu and translate this information into appropriate cellular responses. Epidermal growth factor receptor (EGFR) is the most well-known model in which gene expression is upregulated by mitogenic signals through the activation of multiple signaling cascades or by nuclear translocation of the full-length EGFR protein. RON (Receptuer d'Origine Nantatise, also known as macrophage stimulating 1 receptor, MST1R) has recently gained attention as a therapeutic target for human cancer.
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