2009年6月3日,，北京生命科學(xué)研究所張宏實(shí)驗(yàn)室在Developmental Biology上發(fā)表題為 “The temporally regulated transcription factor SEL-7 controls developmental timing in C. elegans” 的文章,，該文章主要報(bào)道了線蟲的sel-7基因在發(fā)育的時(shí)間調(diào)控過程中的作用。
在多細(xì)胞生物體的發(fā)育過程中,，各個(gè)細(xì)胞的分裂和分化的程序調(diào)控都離不開精密的時(shí)間調(diào)控,。在秀麗線蟲(Caenorhabditis elegans)中，人們已經(jīng)發(fā)現(xiàn)了一系列的異時(shí)性基因參與決定各個(gè)發(fā)育時(shí)期的細(xì)胞行為,。線蟲的側(cè)線細(xì)胞(seam cell)在不同的發(fā)言階段具有不同的細(xì)胞分裂分化行為,，是一個(gè)很好的模型而被廣泛用于發(fā)育的時(shí)間調(diào)控的研究中。
本文報(bào)道了sel-7基因參與決定了線蟲側(cè)線細(xì)胞L3時(shí)期的細(xì)胞命運(yùn),，sel-7的功能性缺失會(huì)導(dǎo)致側(cè)線細(xì)胞L2的細(xì)胞命運(yùn)在L3時(shí)期重復(fù)出現(xiàn),。sel-7之所以能調(diào)控細(xì)胞的命運(yùn)是因?yàn)樗{(diào)節(jié)了hbl-1的時(shí)間表達(dá)模式，而hbl-1是已知的一個(gè)參與L2/L3細(xì)胞命運(yùn)轉(zhuǎn)換的調(diào)控因子,。sel-7是獨(dú)立于其他異時(shí)性基因(lin-46, daf-12和let-7家族miRNA)來抑制L2的細(xì)胞命運(yùn)的滯后表達(dá)的,。sel-7基因本身在側(cè)線細(xì)胞中的表達(dá)也是具有時(shí)間屬性的，這種表達(dá)方式是由一段保守的位于sel-7基因內(nèi)含子里的42bp的序列決定的,。此外,，作者還發(fā)現(xiàn)介導(dǎo)轉(zhuǎn)錄復(fù)合物參與sel-7基因的功能并由此影響側(cè)線細(xì)胞的發(fā)育。本研究發(fā)現(xiàn)了一個(gè)新的受時(shí)間調(diào)控的基因sel-7能調(diào)控側(cè)線細(xì)胞的L2/L3命運(yùn)轉(zhuǎn)換并證明了介導(dǎo)轉(zhuǎn)錄復(fù)合物也參與了線蟲側(cè)線細(xì)胞的時(shí)間信息的整合傳遞,。
博士生夏丹為本文第一作者,，論文的其他作者還有北京生命科學(xué)研究所的黃鑫欣,。張宏博士為本文通訊作者。此項(xiàng)研究由科技部863計(jì)劃,，北京市科委資助,，在北京生命科學(xué)研究所完成。（生物谷Bioon.com）
生物谷推薦原始出處：
Developmental Biology doi:10.1016/j.ydbio.2009.05.574
The temporally regulated transcription factor SEL-7 controls developmental timing in C. elegans
Dan Xiaa, Xinxin Huanga and Hong Zhang, a,
aNational Institute of Biological Sciences, No. 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, PR China
The temporal sequence of cell division and differentiation is explicitly controlled for succession and synchrony of developmental events. In this study we describe how the Caenorhabditis elegans gene sel-7 specifies the L3 stage-specific fate of seam cells, which adopt temporal specificities at each of four larval stages. Loss of function of sel-7 causes reiteration of the L2 stage fate at the L3 stage. sel-7 is involved in regulating the temporal expression pattern of hbl-1, which is a key factor in specifying the L2/L3 progression. We also show that sel-7 functions redundantly with other retarded heterochronic genes, including lin-46, daf-12 and the let-7 family miRNAs, in preventing adoption of the L2 fate at later stages. Expression of sel-7 in seam cells is temporally regulated through an evolutionarily conserved regulatory element located in intron 4 of sel-7. We further demonstrate that reiteration of the L2 proliferative seam cell division at the L3 stage in sel-7 mutants requires activity of the transcriptional mediator complex. Our study reveals that sel-7 functions as a novel heterochronic gene in controlling temporal cell identities and also demonstrates a role of the transcriptional mediator complex in integrating temporal information to specify seam cell division patterns in C. elegans.
