A VPE-like protease NtTPE8 exclusively expresses in the integumentary tapetum and is involved in seed development  

作　　者：Wei Wang Hanxian Xiong Rongxin Lin Nantian Zhao Peng Zhao Meng-Xiang Sun 

机构地区：[1]State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University

出　　处：《Journal of Integrative Plant Biology》2019年第5期598-610,共13页植物学报（英文版）

基　　金：supported by National Natural Science Foundation of China Key Project (31630094);National Natural Science Foundation of China Project (31400171);Young Elite Scientists Sponsorship Program by CAST (YESS) (2015QNRC001)

摘　　要：Programmed cell death(PCD)is an essential process for development,and shows conserved cytological features in both plants and animals.Caspases are well-known critical components of the PCD machinery in animals.However,currently few typical counterparts have been identified in plants and only several caspase-like proteases are known to be involved in plant PCD,indicating the existence of great challenge for confirming new caspase-like proteases and elucidating the mechanisms regulating plant PCD.Here,we report a novel cysteine protease,NtTPE8,which was extracted from tobacco seeds and confirmed as a new caspase-like protease.Recombinant NtTPE8 exhibited legumain and caspase-like proteolytic activities,both of which could be inhibited by the pan-caspase inhibitor(Z-VAD-FMK).Notably,NtTPE8 possessed several caspase activities and the capacity to cleave the cathepsin H substrate FVR,indicating a unique character of NtTPE8.NtTPE8 was exclusively expressed in the integumentary tapetum and thus,is the first specific molecular marker reported to date for this cell type.Downregulation of NtTPE8 caused seed abortion,via disturbing early embryogenesis,indicating its critical role in embryogenesis and seed development.In conclusion,we identified a novel caspase-like cysteine protease,NtTPE8,exclusively expressed in the integumentary tapetum that is involved in seed development.Programmed cell death(PCD) is an essential process for development, and shows conserved cytological features in both plants and animals. Caspases are well-known critical components of the PCD machinery in animals. However, currently few typical counterparts have been identified in plants and only several caspase-like proteases are known to be involved in plant PCD, indicating the existence of great challenge for confirming new caspase-like proteases and elucidating the mechanisms regulating plant PCD. Here, we report a novel cysteine protease, NtTPE8, which was extracted from tobacco seeds and confirmed as a new caspase-like protease.Recombinant NtTPE8 exhibited legumain and caspase-like proteolytic activities, both of which could be inhibited by the pan-caspase inhibitor(Z-VAD-FMK). Notably, NtTPE8 possessed several caspase activities and the capacity to cleave the cathepsin H substrate FVR, indicating a unique character of NtTPE8. NtTPE8 was exclusively expressed in the integumentary tapetum and thus, is the first specific molecular marker reported to date for this cell type. Downregulation of NtTPE8 caused seed abortion, via disturbing early embryogenesis, indicating its critical role in embryogenesis and seed development. In conclusion, we identified a novel caspase-like cysteine protease, NtTPE8,exclusively expressed in the integumentary tapetum that is involved in seed development.

关 键 词：Programmed cell DEATH shows CONSERVED cytological exclusively EXPRESSED 

分 类 号：Q[生物学]