Activated mature B cells in which the DNA-binding activity of E-proteins has been disrupted fail to undergo class switch recombination. Here we show that activated B cells overexpressing the antagonist helix-loop-helix protein Id3 do not induce expression of the murine Aicda gene encoding activation-induced deaminase (AID). A highly conserved intronic regulatory element in Aicda binds E-proteins both in vitro and in vivo. The transcriptional activity of this element is regulated by E-proteins. We show that the enforced expression of AID in cells overexpressing Id3 partially restores class switch recombination. Taken together, our observations link helix-loop-helix activity and Aicda gene expression in a common pathway, in which E-protein activity is required for the efficient induction of Aicda transcription.
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http://dx.doi.org/10.1038/ni923 | DOI Listing |
Int J Biol Macromol
January 2025
Henan Province Engineering Research Center of Innovation for Synthetic Biology, School of Life Sciences and Technology, Xinxiang Medical University, Xinxiang, 453003, Henan, China; School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, 453003, Henan, China. Electronic address:
The mechanisms underlying antigen receptor germline gene diversification have always been a topic of intensive study. Here, we discovered that the frequency of stem-loop sequences in the antigen receptor germline gene region is remarkably higher than the genomic background. By analyzing these stem-loop sequences' similarity and distribution patterns, we found that clustered regularly interspaced homologous stem-loop pairs (CRIHSP) are widely present on the germline genes of antigen receptors in different species.
View Article and Find Full Text PDFFish Shellfish Immunol
January 2025
College of Animal Science and Technology, Jilin Agriculture Science and Technology University, Jilin City, China. Electronic address:
Emamectin benzoate (EMB) is an antibiotic insecticide pesticide modified from avermectin. In the current study, we performed an in-depth investigation of the protective effects of epicatechin on EMB-induced liver injury in common carps. The carps were cultured in an aquatic environment containing 2.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Program in Genetics, Molecular, and Cellular Biology, Tufts University Graduate School of Biomedical Sciences, Boston, MA 02111.
CAG/CTG repeats are prone to expansion, causing several inherited human diseases. The initiating sources of DNA damage which lead to inaccurate repair of the repeat tract to cause expansions are not fully understood. Expansion-prone CAG/CTG repeats are actively transcribed and prone to forming stable R-loops with hairpin structures forming on the displaced single-stranded DNA (S-loops).
View Article and Find Full Text PDFNat Commun
December 2024
Division of Protein & Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
The rate and pattern of mutagenesis in cancer genomes is significantly influenced by DNA accessibility and active biological processes. Here we show that efficient sites of replication initiation drive and modulate specific mutational processes in cancer. Sites of replication initiation impede nucleotide excision repair in melanoma and are off-targets for activation-induced deaminase (AICDA) activity in lymphomas.
View Article and Find Full Text PDFJ Biol Chem
December 2024
School of Environmental Science and Engineering, Shandong University, Qingdao, China. Electronic address:
Base editing is preferable for bacterial gene inactivation without generating double-strand breaks, requiring homology recombination, or highly efficient DNA delivery capability. However, the potential of base editing is limited by the adjoined dependence on the editing window and protospacer adjacent motif. Herein, we report an unconstrained base-editing system to enable the inactivation of any genes of interest in bacteria.
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