Cloning and functional characterization of the Lymantria dispar initiator caspase dronc

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• 作者：Koji Kitaguchi ; Rina Hamajima ; Hayato Yamada ; Michihiro Kobayashi ; Motoko Ikeda
• 关键词：Dronc ; Initiator caspase ; Lymantria dispar ; Bombyx mori ; Baculovirus ; NPV
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2013
• 出版时间：28 June, 2013
• 年：2013
• 卷：436
• 期：2
• 页码：331-337
• 全文大小：862 K

文摘

Ld652Y cells from the gypsy moth, Lymantria dispar, are extremely sensitive to various apoptotic stimuli, whereas BM-N cells from the silkworm, Bombyx mori, are relatively resistant to apoptotic stimuli. We previously cloned and characterized a B. mori homologue (bm-dronc) of Drosophila melanogaster dronc. In the present study, we cloned and characterized an L. dispar homologue of dronc (ld-dronc) comparatively with Bm-Dronc. The open reading frame of ld-dronc consisted of 1329 bp that was predicted to encode a 443 amino-acid polypeptide with a molecular mass of 50,706 Da and 54-57 % amino acid sequence identity with Dronc homologues from other lepidopteran insects identified to date. Ld-Dronc had a long prodomain, large p20 domain, and small p10 domain, and a catalytic site composed of ³⁰⁸QTCRG³¹², which was distinct from the sites QACRG in Bm-Dronc and QMCRG in Dronc homologues of several other lepidopteran insects. Transiently expressed Ld-Dronc underwent proteolytic processing in the lepidopteran cell lines L. dispar Ld652Y, Spodoptera frugiperda Sf9, and B. mori BM-N, and dipteran D. melanogaster S2, but only triggered apoptosis in the lepidopteran cell lines. Endogenous Ld-Dronc underwent processing in Ld652Y cells upon infection with vAc¦¤p35, but not in mock-infected Ld652Y cells, supporting the involvement of Ld-Dronc in apoptosis induction. In vAc¦¤p35-infected apoptotic cells, Ld-Dronc underwent proteolytic processing more rapidly and extensively than Bm-Dronc. Similar results were obtained for Ld-Dronc and Bm-Dronc expressed transiently in S2, Ld652Y, Sf9, and BM-N cells. Taken together, these findings suggest that the intrinsic properties of Dronc proteinsare responsible, at least in part, for the differing sensitivity of Ld652Y and BM-N to apoptosis induction upon NPV infection.