Rice Papers

Nature ，8 February 2010

Control of Arabidopsis apical–basal embryo polarity by antagonistic transcription factors

我们知道细胞都有极性，胚更有apical–basal axis，将来会分化出shoot/root顶端分生组织，目前知道这种极性是由PLETHORA (PLT) genes所控制，这篇文章找到了PLT1 and PLT2所直接调控的转录共抑制子TOPLESS(TPL)，并且利用TPL作为遗传材料，还找到了HD-ZIP III家族基因也起着重要调控作用，他们足可以使root pole into a second shoot pole，这篇文章说明了PLT and HD-ZIP III作为拮抗作用，调节着root and shoot poles的分化。这篇文章faculty1000给了9分，很高的评价，我就看了摘要，写的我自己都看不下去了。

Plants, similarly to animals, form polarized axes during embryogenesis on which cell differentiation and organ patterning programs  are  orchestrated.  During  Arabidopsis  embryogenesis, establishment of the shoot and root stem cell populations occurs at opposite ends of an apical–basal axis. Recent work has identified the PLETHORA (PLT) genes as master regulators of basal/root fate1–3, whereas the master regulators of apical/shoot fate have remained elusive. Here we show that the PLT1 and PLT2 genes are direct targets of the transcriptional corepressor TOPLESS (TPL) and that PLT1/2 are necessary for the homeotic conversion of shoots to roots in tpl-1 mutants. Using tpl-1 as a genetic tool, we identify the CLASS III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIP III) transcription factors as master regulators of embryonic
apical fate, and show they are sufficient to drive the conversion of the embryonic root pole into a second shoot pole. Furthermore, genetic and misexpression studies show an antagonistic relationship between the PLT and HD-ZIP III genes in specifying the root and shoot poles.