title: Juvenile hormone differentially regulates twoGrp78genes encoding protein chaperones required for insect fat body cell homeostasis and vitellogenesis.
abstract: Juvenile hormone (JH) has a well known role in stimulating insect vitellogenesis (i.e.yolk deposition) and oocyte maturation, but the molecular mechanisms of JH action in insect reproduction are unclear. The 78-kDa glucose-regulated protein (Grp78) is a heat shock protein 70-kDa family member and one of the most abundant chaperones in the endoplasmic reticulum (ER) where it helps fold newly synthesized peptides. Because of its prominent role in protein folding, and also ER stress, we hypothesized thatGrp78might be involved in fat body cell homeostasis and vitellogenesis and a regulatory target of JH. We report here that the migratory locustLocusta migratoriapossesses twoGrp78genes that are differentially regulated by JH. We found thatGrp78-1is regulated by JH through Mcm4/7-dependent DNA replication and polyploidization, whereasGrp78-2expression is directly activated by the JH-receptor complex comprising methoprene-tolerant and Taiman proteins. Interestingly,Grp78-2expression in the fat body is about 10-fold higher than that ofGrp78-1Knockdown of eitherGrp78-1orGrp78-2significantly reduced levels of vitellogenin (Vg) protein, accompanied by retarded maturation of oocytes. Depletion of bothGrp78-1andGrp78-2resulted in ER stress and apoptosis in the fat body and in severely defective Vg synthesis and oocyte maturation. These results indicate a crucial role of Grp78 in JH-dependent vitellogenesis and egg production. The presence and differential regulation of twoGrp78genes inL. migratorialikely help accelerate the production of this chaperone in the fat body to facilitate folding of massively synthesized Vg and other proteins.
authors.affiliation: From the State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101.|the University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Maowu
authors.initials: M
authors.lastname: Luo
authors.affiliation: the State Key laboratory of Cotton Biology, Institute of Plant Stress Biology, School of Life Sciences, Henan University, Kaifeng, Henan 475004, and.
authors.forename: Dong
authors.initials: D
authors.lastname: Li
authors.affiliation: From the State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101.
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Wang
authors.affiliation: From the State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101.
authors.forename: Wei
authors.initials: W
authors.lastname: Guo
authors.affiliation: From the State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, lkang@ioz.ac.cn.
authors.forename: Le
authors.initials: L
authors.lastname: Kang
authors.affiliation: the State Key laboratory of Cotton Biology, Institute of Plant Stress Biology, School of Life Sciences, Henan University, Kaifeng, Henan 475004, and szhou@henu.edu.cn.
authors.forename: Shutang
authors.initials: S
authors.lastname: Zhou
mesh_terms: D000818:Animals; D000091342:Endoplasmic Reticulum Chaperone BiP; D005216:Fat Body / Q000378:metabolism*; D005260:Female; D055785:Gene Knockdown Techniques; D006360:Heat-Shock Proteins / Q000096:biosynthesis* / Q000235:genetics; D007605:Juvenile Hormones / Q000235:genetics / Q000378:metabolism*; D048188:Locusta migratoria / Q000235:genetics / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism; D014818:Vitellogenesis / Q000502:physiology*; D014819:Vitellogenins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins; D007605:Juvenile Hormones; D014819:Vitellogenins
keywords: GRP78; apoptosis; endoplasmic reticulum stress (ER stress); homeostasis; juvenile hormone (JH); vitellogenesis