RAG1 and RAG2 catalyze the first DNA cleavage steps in V(D)J recombination. We demonstrate that the isolated central domain of RAG1 has inherent single-stranded (ss) DNA cleavage activity, which does not require, but is enhanced by, RAG2. The central domain, therefore, contains the active-site residues necessary to perform hydrolysis of the DNA phosphodiester backbone. Furthermore, the catalytic activity of this domain on ss DNA is abolished by addition of the C-terminal domain of RAG1. The inhibitory effects of this latter domain are suppressed on substrates containing double-stranded (ds) DNA. Together, the activities of the reconstituted domains on ss versus mixed ds-ss DNA approximate the activity of intact RAG1 in the presence of RAG2. We propose how the combined actions of the RAG1 domains may function in V(D)J recombination and also in aberrant cleavage reactions that may lead to genomic instability in B and T lymphocytes.
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http://dx.doi.org/10.1128/MCB.24.15.6850-6860.2004 | DOI Listing |
Nucleic 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
A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia.
Apurinic/apyrimidinic (AP) sites are endogenous DNA lesions widespread in human cells. Having no nucleobases, they are noncoding and promutagenic. AP site repair is generally initiated through strand incision by AP endonuclease 1 (APE1).
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Medicines Discovery Institute, Cardiff University, Cardiff CF10 3AT, UK.
DNA gyrase is a bacterial type IIA topoisomerase that can create temporary double-stranded DNA breaks to regulate DNA topology and an archetypical target of antibiotics. The widely used quinolone class of drugs use a water-metal ion bridge in interacting with the GyrA subunit of DNA gyrase. Zoliflodacin sits in the same pocket as quinolones but interacts with the GyrB subunit and also stabilizes lethal double-stranded DNA breaks.
View Article and Find Full Text PDFPlants (Basel)
January 2025
College of Forestry and Landscape Architecture, Xinjiang Agricultural University, Urumqi 830052, China.
Rice is exposed to attacks by the three most destructive pathogens, (), pv. (), and (), which cause substantial yield losses and severely threaten food security. To cope with pathogenic infections, rice has evolved diverse molecular mechanisms to respond to a wide range of pathogens.
View Article and Find Full Text PDFAnal Chim Acta
January 2025
Department of Laboratory Medicine, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, People's Republic of China; Wuhan Research Center for Infectious Diseases and Cancer, Chinese Academy of Medical Sciences, Wuhan, People's Republic of China; Hubei Engineering Center for Infectious Disease Prevention, Control and Treatment, Wuhan, People's Republic of China. Electronic address:
Background: In current years, the CRISPR (clustered regularly interspaced short palindromic repeats) based strategies have emerged as the most promising molecular tool in the field of gene editing, intracellular imaging, transcriptional regulation and biosensing. However, the recent CRISPR-based diagnostic technologies still require the incorporation of other amplification strategies (such as polymerase chain reaction) to improve the cis/trans cleavage activity of Cas12a, which complicates the detection workflow and lack of a uniform compatible system to respond to the target in one pot.
Results: To better fully-functioning CRISPR/Cas12a, we reported a novel technique for straightforward nucleic acid detection by incorporating enzyme-responsive steric hindrance-based branched inhibitors with CRISPR/AsCas12a methodology.
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