MicroRNAs (miRNAs) are ~22-nt single-stranded noncoding RNAs with regulatory roles in a wide range of cellular functions by repressing eukaryotic gene expression at a post-transcriptional level. Here, we analyzed the effects on meiosis and fertility of hypomorphic or null alleles of the HYL1, HEN1, DCL1, HST and AGO1 genes, which encode miRNA-machinery components in Arabidopsis. Reduced pollen and megaspore mother cell number and fertility were shown by the mutants analyzed. These mutants also exhibited a relaxed chromatin conformation in male meiocytes at the first meiotic division, and increased chiasma frequency, which is likely to be due to increased levels of mRNAs from key genes involved in homologous recombination. The hen1-13 mutant was found to be hypersensitive to gamma irradiation, which mainly causes double-strand breaks susceptible to be repaired by homologous recombination. Our findings uncover a role for miRNA-machinery components in Arabidopsis meiosis, as well as in the repression of key genes required for homologous recombination. These genes seem to be indirect miRNA targets.
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http://dx.doi.org/10.1038/s41598-017-07702-x | DOI Listing |
Nucleic Acids Res
December 2024
The David and Inez Myers Laboratory for Cancer Research, Tel Aviv University, Tel Aviv 6997801, Israel.
Cellular senescence plays a significant role in tissue aging. Senescent cells, which resist apoptosis while remaining metabolically active, generate endogenous DNA-damaging agents, primarily reactive oxygen species. Efficient DNA repair is therefore crucial in these cells, especially when they undergo senescence escape, resuming DNA replication and cellular proliferation.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Department of Biochemistry and Molecular Biology, College of Life Sciences, Shandong Normal University, Jinan, Shandong 250014, China.
Poly(ADP-ribose) polymerase 1 (PARP1) plays a crucial role in DNA repair and genomic stability maintenance. However, the regulatory mechanisms governing PARP1 activity, particularly through deubiquitination, remain poorly elucidated. Using a deubiquitinase (DUB) library binding screen, we identified cylindromatosis (CYLD) as a bona fide DUB for PARP1 in breast cancer cells.
View Article and Find Full Text PDFBlood Res
December 2024
Division of Laboratory Hematology and Blood Banking, Department of Medical Laboratory Sciences, School of Paramedical Sciences, Shiraz University of Medical Sciences, Meshkin Fam Street, P.O. Box, Shiraz, 71345-1744, Iran.
Background: Acute myeloid leukemia (AML) is a heterogeneous malignancy that responds to various therapies. The sensitivity of leukemia cells to chemotherapy is affected by the DNA damage response (DDR). In this study, we examined the association between RAD51 rs1801320, XRCC3 rs861539, NBS1 rs1805794, MRE11 rs569143, and RAD50 rs2299014 variants of the homologous recombination repair (HRR) pathway and AML outcomes.
View Article and Find Full Text PDFChromosomal instability (CIN) is common in solid tumours and fuels evolutionary adaptation and poor prognosis by increasing intratumour heterogeneity. Systematic characterization of driver events in the TRACERx non-small-cell lung cancer (NSCLC) cohort identified that genetic alterations in six genes, including FAT1, result in homologous recombination (HR) repair deficiencies and CIN. Using orthogonal genetic and experimental approaches, we demonstrate that FAT1 alterations are positively selected before genome doubling and associated with HR deficiency.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Molecular Oncology, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.
CHAMP1 (chromosome alignment-maintaining phosphoprotein 1) plays a role in the repair of DNA double-strand breaks (DSBs) by homologous recombination (HR). The CHAMP1 gene is one of the genes mutated in individuals with intellectual disability. The majority of the mutations are premature termination codon (PTC) mutations, while missense mutations have also been reported.
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