Histone3 lysine4 trimethylation regulated by the facilitates chromatin transcription complex is critical for DNA cleavage in class switch recombination.

Stanlie, Andre; Aida, Masatoshi; Muramatsu, Masamichi; Honjo, Tasuku; Begum, Nasim A · Proc Natl Acad Sci U S A · 2010

basic_science · Level V

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Abstract

Ig class switch recombination (CSR) requires expression of activation-induced cytidine deaminase (AID) and transcription through target switch (S) regions. Here we show that knockdown of the histone chaperone facilitates chromatin transcription (FACT) completely inhibited S region cleavage and CSR in IgA-switch-inducible CH12F3-2A B cells. FACT knockdown did not reduce AID or S region transcripts but did decrease histone3 lysine4 trimethylation (H3K4me3) at both the Sμ and Sα regions. Because knockdown of FACT or H3K4 methyltransferase cofactors inhibited DNA cleavage in H3K4me3-depleted S regions, H3K4me3 may serve as a mark for recruiting CSR recombinase. These findings revealed an unexpected evolutionary conservation between CSR and meiotic recombination.

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