英国约翰英纳斯中心Robert Sablowski课题组发现，植物使用DNA含量来控制细胞大小。2021年6月11日出版的《科学》杂志发表了这项成果。

研究人员表明，在拟南芥芽干细胞微环境中，通过调整DNA合成前的生长期来纠正由不对称分裂引起的细胞大小变化。KIP相关蛋白4（KRP4）抑制DNA合成的进展并与有丝分裂染色体相关联。F BOX-LIKE 17（FBL17）蛋白去除多余的KRP4。因此，子细胞出生时具有相当数量的KRP4。

抑制剂稀释模型预测，通过染色质遗传的KRP4会强有力地调节大小，而过量游离KRP4的遗传会破坏大小稳态，正如突变分析所证实的那样。研究人员提出，通过与有丝分裂染色体相关联而稳定的细胞周期调节因子将DNA含量作为与细胞大小非依赖的标尺来读取。

据悉，真核细胞如何评估和维持特定于其物种和细胞类型的大小仍不清楚。

附：英文原文

Title: Cell size controlled in plants using DNA content as an internal scale

Author: Marco D’Ario, Rafael Tavares, Katharina Schiessl, Bénédicte Desvoyes, Crisanto Gutierrez, Martin Howard, Robert Sablowski

Issue&Volume: 2021/06/11

Abstract: How eukaryotic cells assess and maintain sizes specific for their species and cell type remains unclear. We show that in the Arabidopsis shoot stem cell niche, cell size variability caused by asymmetric divisions is corrected by adjusting the growth period before DNA synthesis. KIP-related protein 4 (KRP4) inhibits progression to DNA synthesis and associates with mitotic chromosomes. The F BOX-LIKE 17 (FBL17) protein removes excess KRP4. Consequently, daughter cells are born with comparable amounts of KRP4. Inhibitor dilution models predicted that KRP4 inherited through chromatin would robustly regulate size, whereas inheritance of excess free KRP4 would disrupt size homeostasis, as confirmed by mutant analyses. We propose that a cell cycle regulator, stabilized by association with mitotic chromosomes, reads DNA content as a cell size–independent scale.

DOI: 10.1126/science.abb4348

Source: https://science.sciencemag.org/content/372/6547/1176