北京林业大学研究植物绒毡层细胞程序化死亡机制取得重要进展。7月17日，该校生物学院陆海教授团队获得的有关新成果在《植物细胞》在线发表。

该研究首次阐述了半胱氨酸蛋白酶在绒毡层细胞的适时降解过程中的关键控制作用，为从细胞及分子水平上阐明植物花药绒毡层细胞程序化死亡和花粉成熟的调控机制奠定了理论基础；证明了papain类蛋白酶是植物细胞程序化死亡的关键控制基因，为分析植物细胞程序化死亡的调控机制提供了有益而重要的理论参考。

动植物等多细胞生物体在发育过程中,或在某些环境因子的作用下发生的受基因调控的主动死亡过程,被科学家们称为细胞程序化死亡。在此过程中，蛋白酶起着重要作用。蛋白酶基因普遍存在表达模式和生化功能的冗余，其分子机制很难得到准确鉴定。植物花药绒毡层的降解是典型的细胞程序化死亡的过程。该过程的实际控制和执行因子一直没有得到明确阐述。

陆海及其课题组以拟南芥花药为实验材料，详细比较了拟南芥野生型、突变体、过表达等不同株系中花药绒毡层的细胞程序化死亡的过程，发现半胱氨酸蛋白酶基因CEP1控制这一进程，是主要执行者和控制者。（来源：中国科学报 铁铮 杨丽娜）

The Cysteine Protease CEP1, a Key Executor Involved in Tapetal Programmed Cell Death, Regulates Pollen Development in Arabidopsis[

Abstract  Tapetal programmed cell death (PCD) is a prerequisite for pollen grain development in angiosperms, and cysteine proteases are the most ubiquitous hydrolases involved in plant PCD. We identified a papain-like cysteine protease, CEP1, which is involved in tapetal PCD and pollen development in Arabidopsis thaliana. CEP1 is expressed specifically in the tapetum from stages 5 to 11 of anther development. The CEP1 protein first appears as a proenzyme in precursor protease vesicles and is then transported to the vacuole and transformed into the mature enzyme before rupture of the vacuole. cep1 mutants exhibited aborted tapetal PCD and decreased pollen fertility with abnormal pollen exine. A transcriptomic analysis revealed that 872 genes showed significantly altered expression in the cep1 mutants, and most of them are important for tapetal cell wall organization, tapetal secretory structure formation, and pollen development. CEP1 overexpression caused premature tapetal PCD and pollen infertility. ELISA and quantitative RT-PCR analyses confirmed that the CEP1 expression level showed a strong relationship to the degree of tapetal PCD and pollen fertility. Our results reveal that CEP1 is a crucial executor during tapetal PCD and that proper CEP1 expression is necessary for timely degeneration of tapetal cells and functional pollen formation.

原文链接：http://www.plantcell.org/content/early/2014/07/17/tpc.114.127282.full.pdf+html