PLC低温春化信号传递介绍.ppt

The FLC gene is epigenetically modified during vernalization It is consistent with this model that VIN3 is clearly the most upstream component of vernalization so far identi?ed because vin3 is the only mutantin which FLC repression is blocked during cold exposure, and in which no histone modi?cations are detected during vernalization. 2.Epigenetic maintenance of the vernalized statein Arabidopsis thaliana requires LIKE HETEROCHROMATINPROTEIN1 Reprinted by permission from Macmillan Publishers, Ltd: NATURE GENETICS. Sung, S., He, Y., Eshoo, T.W., Tamada, Y., Johnson, L., Nakahigashi, K., Goto, K., Jacobsen, S.E., and Amasino. R.M. (2006) Epigenetic maintenance of the vernalized state in Arabidopsis thaliana requires LIKE HETEROCHROMATIN PROTEIN 1. Nature Genetics 38: 706 – 710. Copyright 2006. Here, we report that A.thaliana LIKE HETEROCHROMATIN PROTEIN1(LHP1) isnecessary to maintain the epigenetically repressed state of FLC upon return to warm conditions typical of spring. LHP1 is enriched at FLC chromatin after prolonged exposure to cold,and LHP1 activity is needed to maintain the increased levels of H3K9 dimethylation at FLC chromatin that are characteristic of the vernalized state. A 2.8-kb region of the ?rst intron of FLC is required for stable maintenance of FLC repression. We ?nd that a deletion of just 289bp is suf?cient to prevent maintenance of the silenced state of FLC. The VRE region may serve as a site of recruitment of a vernalization-speci?c, chromatin-remodeling complex that isrequired for the initial increase in H3K9 dimethylation. Elevated H3K9 dimethylation alone is not suf?cient to recruit LHP1, becausenot all chromatin with elevated levels of H3K9 dimethylationis associated with LHP1; therefore, additional factors, perhaps associated with theVRE, are required for LHP1 recruitment and stable silencing of euchromatic genes. 谢谢！ * H2A H2B H3 H4 A partial list of histone modifications in Arabidopsis (Zhang et al. 2008) Histone modifi