Programmed Cell Death of the Megagametophyte during Post-germinative Growth of White Spruce (Picea glauca) Seeds is Regulated by Reactive Oxygen Species and the Ubiquitin-mediated Proteolytic System
Programmed Cell Death of the Megagametophyte during Post-germinative Growth of White Spruce (Picea glauca) Seeds is Regulated by Reactive Oxygen Species and the Ubiquitin-mediated Proteolytic System
复制标题
DOI：
10.1093/pcp/pcq130
复制
发表时间：
2010-10-01
影响因子：
4.9
通讯作者：
Kermode, Allison R.
中科院分区：
文献类型：
--
作者：
He, Xu;Kermode, Allison R.
白色云杉（Picea glauca）种子的巨配子体在种子萌发后经历程序性细胞死亡。这一过程的特点是独特的形态和生化特征，如DNA片段化和蛋白酶的诱导。种子萌发后，在巨配子体中检测到过氧化氢的双相生产。ROS清除剂或ROS产生抑制剂降低了半胱天冬酶样蛋白酶活性，减缓了细胞死亡的进程。白色云杉的一种过氧化氢酶（CAT）与针对棉籽CAT的抗体发生反应，克隆了相应的CAT基因，并与其他植物物种的过氧化氢酶基因进行了比较。通过酪氨酸磷酸化刺激白色云杉CAT酶的活性。磷酸化的CAT被泛素化并被蛋白酶体降解。此外，蛋白酶体抑制剂MG 132抑制CAT的降解，并延迟细胞死亡。这些结果表明，CAT和泛素介导的蛋白水解系统的相互作用是至关重要的ROS的生产和随后的细胞死亡的控制。
The megagametophyte of white spruce (Picea glauca) seeds undergoes programmed cell death following seed germination. This process is characterized by distinct morphological and biochemical features, such as DNA fragmentation and the induction of proteases. Biphasic production of hydrogen peroxide was detected in the megagametophyte following seed germination. ROS scavengers or inhibitors of ROS production decreased caspase-like protease activity and slowed the progression of cell death. One catalase (CAT) of white spruce reacted with antibodies directed against cotton-seed CAT. The corresponding CAT gene was cloned and compared with the catalase genes of other plant species. The activity of the white spruce CAT enzyme was stimulated by tyrosine phosphorylation. The phosphorylated CAT was subjected to ubiquitination and degraded by the proteasome. Furthermore, the proteasome inhibitor MG132 inhibited the degradation of CAT and delayed cell death. These results suggest that the interplay of CAT and the ubiquitin-mediated proteolytic system is critical in the control of ROS production and subsequent cell death.