Structural highlights
Function[SWI6_SCHPO] Recognizes and binds histone H3 tails methylated at 'Lys-9', leading to epigenetic repression. Involved in the repression of the silent mating-type loci MAT2 and MAT3. May compact MAT2/3 into a heterochromatin-like conformation which represses the transcription of these silent cassettes. Publication Abstract from PubMedCentromeric heterochromatin assembly in fission yeast requires the RNAi pathway. Chp1, a chromodomain (CD) protein, forms the Ago1-containing RNA-induced transcriptional silencing (RITS) complex and recruits siRNA-bound RITS to methylated histone H3 lysine 9 (H3K9me) via its CD. Here, we show that the CD of Chp1 (Chp1-CD) possesses unique nucleic acid-binding activities that are essential for heterochromatic gene silencing. Detailed electrophoretic-mobility shift analyses demonstrated that Chp1 binds to RNA via the CD in addition to its central RNA-recognition motif. Interestingly, robust RNA- and DNA-binding activity of Chp1-CD was strongly enhanced when it was bound to H3K9me, which was revealed to involve a positively charged domain within the Chp1-CD by structural analyses. These results demonstrate a role for the CD that provides a link between RNA, DNA, and methylated histone tails to ensure heterochromatic gene silencing. Intrinsic nucleic Acid-binding activity of chp1 chromodomain is required for heterochromatic gene silencing.,Ishida M, Shimojo H, Hayashi A, Kawaguchi R, Ohtani Y, Uegaki K, Nishimura Y, Nakayama J Mol Cell. 2012 Jul 27;47(2):228-41. Epub 2012 Jun 21. PMID:22727667[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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