Functions of the ecdysone receptor isoform-A in the hemimetabolous insect Blattella germanica revealed by systemic RNAi in vivo.
The molecular basis of ecdysteroid function during development has been analyzed in detail in holometabolous insects, especially in Drosophila melanogaster, but rarely in hemimetabolous. Using the hemimetabolous species Blattella germanica (German cockroach) as model, we show that the ecdysone receptor isoform-A (BgEcR-A) mRNA is present throughout the penultimate and last nymphal instars in all tissues analyzed (prothoracic gland, epidermis and fat body). To study the functions of BgEcR-A, we reduced its expression using systemic RNAi in vivo, and we obtained knockdown specimens. Examination of these specimens indicated that BgEcR-A during the last nymphal instar is required for nymphal survival, and that reduced expression is associated with molting defects, lower circulating ecdysteroid levels and defects in cell proliferation in the follicular epithelium. Some BgEcR-A knockdown nymphs survive to the adult stage. The features of these specimens indicate that BgEcR-A is required for adult-specific developmental processes, such as wing development, prothoracic gland degeneration and normal choriogenesis.
Cruz
Josefa
J
Departament de Fisiologia i Biodiversitat Molecular, Institut de Biologia Molecular de Barcelona (CID, CSIC), Jordi Girona 18, 08034 Barcelona, Spain.
Mané-Padrós
Daniel
D
Bellés
Xavier
X
Martín
David
D
D000595:Amino Acid Sequence; D000818:Animals; D020048:Blattellidae / Q000235:genetics / Q000254:growth & development*; D049109:Cell Proliferation; D003001:Cloning, Molecular; D004441:Ecdysterone / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D018507:Gene Expression Regulation, Developmental; D019476:Insect Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D018978:Molting; D009758:Nymph / Q000235:genetics; D009866:Oogenesis / Q000502:physiology; D006080:Ovarian Follicle / Q000166:cytology; D034622:RNA Interference; D011987:Receptors, Steroid / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014921:Wings, Animal / Q000254:growth & development
D019476:Insect Proteins; D011987:Receptors, Steroid; C467903:ecdysone receptor A, insect; D004441:Ecdysterone