“春化”是植物繼寒冬之后在春天獲得根據(jù)環(huán)境提示來(lái)開(kāi)花的能力的過(guò)程,，是植物的一個(gè)關(guān)鍵適應(yīng)性特征,，對(duì)農(nóng)業(yè)生產(chǎn)有較大影響,。擬南芥開(kāi)花抑制因子FLC在由Polycomb調(diào)控蛋白調(diào)節(jié)的一個(gè)過(guò)程中被“春化”關(guān)閉,。
現(xiàn)在,，F(xiàn)LC的非編碼反義RNA轉(zhuǎn)錄體被發(fā)現(xiàn)存在于冷處理的種子中，并對(duì)溫度變化有響應(yīng),，這說(shuō)明它們?cè)诘蜏馗袘?yīng)和FLC沉默中有可能扮演一個(gè)角兒,。這種類(lèi)型的反義轉(zhuǎn)錄事件（源自基因的3′端）也許是調(diào)控相應(yīng)“正義”轉(zhuǎn)錄的一個(gè)普遍機(jī)制。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 462, 799-802 (10 December 2009) | doi:10.1038/nature08618
Cold-induced silencing by long antisense transcripts of an Arabidopsis Polycomb target
Szymon Swiezewski1, Fuquan Liu1, Andreas Magusin1 & Caroline Dean1
1 John Innes Centre, Colney, Norwich, NR4 7UH, UK
Correspondence to: Caroline Dean1 Correspondence and requests for materials should be addressed to C.D.
Transcription in eukaryotic genomes generates an extensive array of non-protein-coding RNA, the functional significance of which is mostly unknown1. We are investigating the link between non-coding RNA and chromatin regulation through analysis of FLC?—?a regulator of flowering time in Arabidopsis and a target of several chromatin pathways. Here we use an unbiased strategy to characterize non-coding transcripts of FLC and show that sense/antisense transcript levels correlate in a range of mutants and treatments, but change independently in cold-treated plants. Prolonged cold epigenetically silences FLC in a Polycomb-mediated process called vernalization2. Our data indicate that upregulation of long non-coding antisense transcripts covering the entire FLC locus may be part of the cold-sensing mechanism. Induction of these antisense transcripts occurs earlier than, and is independent of, other vernalization markers3 and coincides with a reduction in sense transcription. We show that addition of the FLC antisense promoter sequences to a reporter gene is sufficient to confer cold-induced silencing of the reporter. Our data indicate that cold-induced FLC antisense transcripts have an early role in the epigenetic silencing of FLC, acting to silence FLC transcription transiently. Recruitment of the Polycomb machinery then confers the epigenetic memory. Antisense transcription events originating from 3′ ends of genes might be a general mechanism to regulate the corresponding sense transcription in a condition/stage-dependent manner.
