在經(jīng)典植物模型擬南芥中對(duì)植物根發(fā)育所做的一項(xiàng)研究發(fā)現(xiàn),，一種微RNA（miRNA165/6）與細(xì)胞間的通信有關(guān),，并且是根細(xì)胞命運(yùn)的一個(gè)決定因子。
將水和溶質(zhì)從根向莖輸送的木質(zhì)部微管的模式形成,，被發(fā)現(xiàn)取決于一個(gè)新穎的雙向信號(hào)作用通道,，該通道涉及一個(gè)轉(zhuǎn)錄因子在一個(gè)方向上、microRNA在另一個(gè)方向上的細(xì)胞到細(xì)胞間的運(yùn)動(dòng),。這個(gè)轉(zhuǎn)錄因子為SHORT ROOT,，是在維管柱中產(chǎn)生的，它進(jìn)入內(nèi)皮中,，在那里與SCARECROW一起激發(fā)微RNA MIR165a 和166b,，后者又回到維管細(xì)胞中，降解它們的目標(biāo),、編碼“Class III homeodomain-leucine zipper”轉(zhuǎn)錄因子的信使RNA,。
這個(gè)調(diào)控通道中由在演化上保守的轉(zhuǎn)錄因子和miRNA組成的一個(gè)級(jí)聯(lián)的參與表明，它也許是對(duì)陸地生長(zhǎng)條件的一種演化適應(yīng),。 （生物谷Bioon.com）
生物谷推薦原文出處：
Nature doi:10.1038/nature08977
Cell signalling by microRNA165/6 directs gene dose-dependent root cell fate
Annelie Carlsbecker1,2,8, Ji-Young Lee3,4,8, Christina J. Roberts2, Jan Dettmer1, Satu Lehesranta1, Jing Zhou3,4, Ove Lindgren1,5, Miguel A. Moreno-Risueno6, Anne Vatén1, Siripong Thitamadee1, Ana Campilho1, Jose Sebastian3, John L. Bowman7, Yk? Helariutta1,8 & Philip N. Benfey6,8
Institute of Biotechnology/Department of Biosciences, University of Helsinki, FIN-00014, Finland
Department of Physiological Botany, Evolutionary Biology Center, Uppsala University, Norbyv?gen 18D, SE-752 36 Uppsala, Sweden
Boyce Thompson Institute for Plant Research, Tower Road, Ithaca, New York 14853, USA
Graduate Field of Plant Biology, Cornell University, Ithaca, New York 14853, USA
Institute of Technology, University of Tartu, Tartu 50411, Estonia
Biology Department and IGSP Center for Systems Biology, Duke University, Durham, North Carolina 27708, USA
School of Biological Sciences, Monash
A key question in developmental biology is how cells exchange positional information for proper patterning during organ development. In plant roots the radial tissue organization is highly conserved with a central vascular cylinder in which two water conducting cell types, protoxylem and metaxylem, are patterned centripetally. We show that this patterning occurs through crosstalk between the vascular cylinder and the surrounding endodermis mediated by cell-to-cell movement of a transcription factor in one direction and microRNAs in the other. SHORT ROOT, produced in the vascular cylinder, moves into the endodermis to activate SCARECROW. Together these transcription factors activate MIR165a and MIR166b. Endodermally produced microRNA165/6 then acts to degrade its target mRNAs encoding class III homeodomain-leucine zipper transcription factors in the endodermis and stele periphery. The resulting differential distribution of target mRNA in the vascular cylinder determines xylem cell types in a dosage-dependent manner.
