title: Mod(mdg4) participates in hormonally regulated midgut programmed cell death during metamorphosis.
abstract: The insect midgut undergoes programmed cell death (PCD) during metamorphosis, but the molecular basis for this phenomenon has not been demonstrated. We report a mod(mdg4) protein [designated as mod(mdg4)1A] that is involved in hormonally regulated insect midgut PCD, from the lepidopteran Helicoverpa armigera. Mod(mdg4)1A is localized in the larval midgut and is highly expressed during metamorphosis. Knockdown of mod(mdg4)1a by feeding dsRNA to the larvae suppressed midgut PCD and delayed metamorphosis. The mechanism is that mod(mdg4)1a knockdown decreased the transcript levels of genes involved in PCD and metamorphosis, but increased the transcript level of inhibitor of apoptosis survivin. The transcript level of mod(mdg4)1a is independently upregulated by 20-hydroxyecdysone (20E) or juvenile hormone (JH) analog methoprene. Overlapped 20E and methoprene counteractively regulate the transcript level of mod(mdg4)1a. 20E upregulates the mod(mdg4)1a transcript level not through its nuclear receptor EcRB1. Methoprene upregulates the mod(mdg4)1a transcript level through the juvenile hormone candidate receptor Met. These findings indicate that mod(mdg4)1a participates in midgut PCD and metamorphosis by regulating the transcript levels of a network of genes via different pathways under 20E and JH regulation.
authors.affiliation: The Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Jinan 250100, China.
authors.forename: Mei-Juan
authors.initials: MJ
authors.lastname: Cai
authors.forename: Wen
authors.initials: W
authors.lastname: Liu
authors.forename: Hong-Juan
authors.initials: HJ
authors.lastname: He
authors.forename: Jin-Xing
authors.initials: JX
authors.lastname: Wang
authors.forename: Xiao-Fan
authors.initials: XF
authors.lastname: Zhao
mesh_terms: D000818:Animals; D017209:Apoptosis; D004064:Digestive System / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics / Q000378:metabolism; D007301:Insect Hormones / Q000378:metabolism*; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D007814:Larva / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D008675:Metamorphosis, Biological; D009036:Moths / Q000166:cytology / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D051034:Inhibitor of Apoptosis Proteins; D007301:Insect Hormones; D019476:Insect Proteins