| Structural highlights
Function
CHP1_SCHPO Component of the kinetochore which plays a role in stabilizing microtubules and so allowing accurate chromosome segregation. Has a role in the RNA interference (RNAi) pathway which is important for heterochromatin formation and accurate chromosome segregation. A member of the RNA-induced transcriptional silencing (RITS) complex which is involved in the biosynthesis of dsRNA from primer siRNAs provided by the RNA-directed RNA polymerase (RDRC) complex.[1] [2] [3] [4]
Publication Abstract from PubMed
Centromeric 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[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Doe CL, Wang G, Chow C, Fricker MD, Singh PB, Mellor EJ. The fission yeast chromo domain encoding gene chp1(+) is required for chromosome segregation and shows a genetic interaction with alpha-tubulin. Nucleic Acids Res. 1998 Sep 15;26(18):4222-9. PMID:9722643
- ↑ Thon G, Verhein-Hansen J. Four chromo-domain proteins of Schizosaccharomyces pombe differentially repress transcription at various chromosomal locations. Genetics. 2000 Jun;155(2):551-68. PMID:10835380
- ↑ Motamedi MR, Verdel A, Colmenares SU, Gerber SA, Gygi SP, Moazed D. Two RNAi complexes, RITS and RDRC, physically interact and localize to noncoding centromeric RNAs. Cell. 2004 Dec 17;119(6):789-802. PMID:15607976 doi:10.1016/j.cell.2004.11.034
- ↑ Verdel A, Jia S, Gerber S, Sugiyama T, Gygi S, Grewal SI, Moazed D. RNAi-mediated targeting of heterochromatin by the RITS complex. Science. 2004 Jan 30;303(5658):672-6. Epub 2004 Jan 2. PMID:14704433 doi:10.1126/science.1093686
- ↑ Ishida M, Shimojo H, Hayashi A, Kawaguchi R, Ohtani Y, Uegaki K, Nishimura Y, Nakayama J. Intrinsic nucleic Acid-binding activity of chp1 chromodomain is required for heterochromatic gene silencing. Mol Cell. 2012 Jul 27;47(2):228-41. Epub 2012 Jun 21. PMID:22727667 doi:10.1016/j.molcel.2012.05.017
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