BmDredd is an initiator caspase and participates in Emodin-induced apoptosis in the silkworm, Bombyx mori.
The identification and analysis of the caspases is essential to research into apoptosis in lepidoptera insects. The domesticated silkworm, Bombyx mori, is the model system for lepidopterans. In this study, we cloned and characterized a B. mori Dredd gene, BmDredd, the proposed insect homologue of human caspase-8, which encoded a polypeptide of 543 amino acids. BmDredd possesses a long N-terminal prodomain, a p20 domain, and a p10 domain. When transiently expressed in Escherichia coli cells, BmDredd underwent spontaneous cleavage and exhibited high proteolytic activity for caspase-8 substrate but relatively low for caspase-3 or -9 substrate. In addition, BmDredd induced apoptosis when transiently expressed in BmN-SWU1 cells, an ovarian cell line of B. mori. Moreover, after the treatment of Emodin, a novel apoptosis inducer, endogenous BmDredd expression level, the caspase-8 activity and the apoptotic rate increased notably in BmN-SWU1 cells. When BmDredd was subjected to interference in BmN-SWU1 cells and Emodin treatment, BmDredd expression levels decreased and the apoptotic rate also decreased significantly. These results suggest BmDredd is the homologue of human caspase-8 and plays a role in Emodin-induced apoptosis in BmN-SWU1 cells of B. mori.
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China; Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing 400716, China.
La
L
Wang
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China.
Juan
J
Song
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China.
Xi-Yan
XY
Bao
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China.
Peng
P
Chen
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China.
Hua-Shan
HS
Yi
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China; Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing 400716, China. Electronic address: pmh047@126.com.
Min-Hui
MH
Pan
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China; Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing 400716, China. Electronic address: lucheng@swu.edu.cn.
Cheng
C
Lu
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D012831:Bombyx / Q000187:drug effects / Q000201:enzymology*; D053181:Caspase 8 / Q000378:metabolism*; D002460:Cell Line; D003001:Cloning, Molecular; D004642:Emodin / Q000494:pharmacology; D004926:Escherichia coli; D017344:Genes, Insect; D006801:Humans; D017422:Sequence Analysis, DNA
D053181:Caspase 8; D004642:Emodin
Apoptosis; BmDredd; Bombyx mori; Caspase; Emodin