A hierarchical transcriptional network activates specific CDK inhibitors that regulate G2 to control cell size and number in Arabidopsis

第一作者：Yuji Nomoto

第一单位：日本金泽大学

通讯作者：Masaki Ito

 Abstarct 

背景回顾：How cell size and number are determined during organ development remains a fundamental question in cell biology. 

细胞大小和数量在器官发育过程中是如何被决定的？这一问题是细胞生物学的基础问题之一。

主要研究：Here, we identified a GRAS family transcription factor, called SCARECROW-LIKE28 (SCL28), with a critical role in determining cell size in Arabidopsis. SCL28 is part of a transcriptional regulatory network downstream of the central MYB3Rs that regulate G2 to M phase cell cycle transition.

本文中，作者鉴定到了GRAS家族成员SCL28在拟南芥的细胞大小决定中扮演关键作用。SCL28是以MYB3Rs为核心的转录调控网络中的一员，该网络主要是参与G2到M期的细胞周期转变。

结果-SCL28-SMOS1-SMRs： We show that SCL28 forms a dimer with the AP2-type transcription factor, AtSMOS1, which defines the specificity for promoter binding and directly activates transcription of a specific set of SIAMESE-RELATED (SMR) family genes, encoding plant-specific inhibitors of cyclin-dependent kinases and thus inhibiting cell cycle progression at G2 and promoting the onset of endoreplication. Through this dose-dependent regulation of SMR transcription, SCL28 quantitatively sets the balance between cell size and number without dramatically changing final organ size. 

作者发现，SCL28能够与AP2类转录因子AtSMOS1形成一个二聚体，后者决定了该复合体的启动子结合特异性，直接激活编码植物特异性细胞周期蛋白依赖激酶抑制因子SMR家族特定一类成员的转录，从而抑制G2期的细胞周期进程，促进核内复制。通过对SMR转录的剂量依赖型调控，SCL28能够在不剧烈改变最终器官大小的前提下，定量设定细胞大小与数量之间的平衡。

结论：We propose that this hierarchical transcriptional network constitutes a cell cycle regulatory mechanism that allows to adjust cell size and number to attain robust organ growth.

作者认为，这种层级转录网络构成了一种细胞周期调控机制，帮助调节细胞大小和数量之间的平衡，以实现器官的稳健生长。

** Masaki Ito **

doi: https://doi.org/10.1038/s41467-022-29316-2

Journal: Nature Communications​

Published date: March 29, 2022