title: Functional role of aspartic proteinase cathepsin D in insect metamorphosis.
abstract: BACKGROUND
  Metamorphosis is a complex, highly conserved and strictly regulated development process that involves the programmed cell death of obsolete larval organs. Here we show a novel functional role for the aspartic proteinase cathepsin D during insect metamorphosis.
  
  
  RESULTS
  Cathepsin D of the silkworm Bombyx mori (BmCatD) was ecdysone-induced, differentially and spatially expressed in the larval fat body of the final instar and in the larval gut of pupal stage, and its expression led to programmed cell death. Furthermore, BmCatD was highly induced in the fat body of baculovirus-infected B. mori larvae, suggesting that this gene is involved in the induction of metamorphosis of host insects infected with baculovirus. RNA interference (RNAi)-mediated BmCatD knock-down inhibited programmed cell death of the larval fat body, resulting in the arrest of larval-pupal transformation. BmCatD RNAi also inhibited the programmed cell death of larval gut during pupal stage.
  
  
  CONCLUSIONS
  Based on these results, we concluded that BmCatD is critically involved in the programmed cell death of the larval fat body and larval gut in silkworm metamorphosis.
authors.affiliation: College of Natural Resources and Life Science, Dong-A University, Busan 604-714, Korea. srizzgui@hotmail.com
authors.forename: Zhong Zheng
authors.initials: ZZ
authors.lastname: Gui
authors.forename: Kwang Sik
authors.initials: KS
authors.lastname: Lee
authors.forename: Bo Yeon
authors.initials: BY
authors.lastname: Kim
authors.forename: Yong Soo
authors.initials: YS
authors.lastname: Choi
authors.forename: Ya Dong
authors.initials: YD
authors.lastname: Wei
authors.forename: Young Moo
authors.initials: YM
authors.lastname: Choo
authors.forename: Pil Don
authors.initials: PD
authors.lastname: Kang
authors.forename: Hyung Joo
authors.initials: HJ
authors.lastname: Yoon
authors.forename: Iksoo
authors.initials: I
authors.lastname: Kim
authors.forename: Yeon Ho
authors.initials: YH
authors.lastname: Je
authors.forename: Sook Jae
authors.initials: SJ
authors.lastname: Seo
authors.forename: Sang Mong
authors.initials: SM
authors.lastname: Lee
authors.forename: Xijie
authors.initials: X
authors.lastname: Guo
authors.forename: Hung Dae
authors.initials: HD
authors.lastname: Sohn
authors.forename: Byung Rae
authors.initials: BR
authors.lastname: Jin
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015152:Blotting, Northern; D015153:Blotting, Western; D012831:Bombyx / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D002402:Cathepsin D / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D053938:DNA Fragmentation / Q000187:drug effects; D004441:Ecdysterone / Q000494:pharmacology; D005216:Fat Body / Q000201:enzymology / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D008675:Metamorphosis, Biological / Q000235:genetics / Q000502:physiology*; D017924:Nucleopolyhedroviruses / Q000235:genetics; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D018411:Spodoptera
chemical_list: D019476:Insect Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D004441:Ecdysterone; D002402:Cathepsin D