DNA-RNA hybrids associated with R-loops promote DNA damage and genomic instability. The capacity of hybrids at different genomic sites to cause DNA damage was not known, and the mechanisms leading from hybrid to damage were poorly understood. Here, we adopt a new strategy to map and characterize the sites of hybrid-induced damage genome-wide in budding yeast. We show that hybrid removal is essential for life because persistent hybrids cause irreparable DNA damage and cell death. We identify that a subset of hybrids is prone to cause damage, and the chromosomal context of hybrids dramatically impacts their ability to induce damage. Furthermore, persistent hybrids affect the repair pathway, generating large regions of single-stranded DNA (ssDNA) by two distinct mechanisms, likely resection and re-replication. These damaged regions may act as potential precursors to gross chromosomal rearrangements like deletions and duplications that are associated with R-loops and cancers.
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http://dx.doi.org/10.1016/j.molcel.2018.06.037 | DOI Listing |
Understanding kinase action requires precise quantitative measurements of their activity . In addition, the ability to capture spatial information of kinase activity is crucial to deconvolute complex signaling networks, interrogate multifaceted kinase actions, and assess drug effects or genetic perturbations. Here we developed a proteomic kinase activity sensor platform (ProKAS) for the analysis of kinase signaling using mass spectrometry.
View Article and Find Full Text PDFThe shelterin complex protects chromosome ends from the DNA damage repair machinery and regulates telomerase access to telomeres. Shelterin is composed of six proteins (TRF1, TRF2, TIN2, TPP1, POT1 and RAP1) that can assemble into various subcomplexes . However, the stoichiometry of the shelterin complex and its dynamic association with telomeres in cells is poorly defined.
View Article and Find Full Text PDFUnlabelled: In vitro fertilization (IVF) is a widely used assisted reproductive technology to achieve a successful pregnancy. However, the acquisition of oxidative stress in embryo in vitro culture impairs its competence. Here, we demonstrated that a nuclear coding gene, methyltransferase- like protein 7A (METTL7A), improves the developmental potential of bovine embryos.
View Article and Find Full Text PDFIn duplex DNA, A-T and G-C form Watson-Crick base pairs, and Hoogsteen pairing only dominates upon protein binding or DNA damage. Using NMR, we show that an A-T Hoogsteen base pair previously observed in crystal structures of transposon DNA hairpins bound to TnpA protein forms in solution even in the absence of TnpA. This Hoogsteen base pair, located adjacent to a dinucleotide apical loop, exists in dynamic equilibrium with a minor Watson-Crick conformation (population ∼11% and lifetime ∼55 µs).
View Article and Find Full Text PDFHuntington's Disease (HD), a progressive neurodegenerative disorder with no disease-modifying therapies, is caused by a CAG repeat expansion in the HD gene encoding polyglutamine-expanded huntingtin (HTT) protein. Mechanisms of HD cellular pathogenesis and cellular functions of the normal and mutant HTT proteins are still not completely understood. HTT protein has numerous interaction partners, and it likely provides a scaffold for assembly of multiprotein complexes many of which may be altered in HD.
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