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Stimulation of vitellogenin production by methoprene in prepupae and pupae of manduca sexta
Author(s) -
Satyanarayana Kotamraju,
Bradfield James Y.,
Bhaskaran Govindan,
Dahm Karl H.
Publication year - 1994
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.940250104
Subject(s) - methoprene , manduca sexta , vitellogenin , juvenile hormone , biology , 20 hydroxyecdysone , hemolymph , medicine , endocrinology , stimulation , protein biosynthesis , microbiology and biotechnology , biochemistry , gene , hormone , insect , botany
Denaturing electrophoresis of hemolymph from prepupae of M. sexta showed trace amounts of polypeptides with mobilities corresponding to those of vitellogenin (Vg) apoproteins from adult females. Absence of the polypeptides in allatectomized insects suggested regulation by juvenile hormone (JH). Daily administration of 10 μg of the JH analog methoprene from day 4 of the fifth stage to day 0 of the pupal stage caused accumulation of these polypeptides. They were identified as apovitellogenins (apoVgs) immunochemically with Vg antiserum. Stimulation of Vg in response to methoprene varied with age. In all cases, day 0 female pupae were highly responsive. Vg synthesis was not stimulated when pupae were injected with 20‐hydroxyecdysone (20‐HE) in addition to methoprene. Methoprene‐stimulated Vg synthesis was also abolished by inhibitors of mRNA or protein synthesis (α‐amanitin, actinomycin, cycloheximide). This result indicated that methoprene‐stimulated Vg accumulation requires gene expression. A Vg cDNA (2.1 kb) obtained by immunoscreening of the λgt 11 library, when used as a radiolabelled probe, hybridized with a 5.1 kb mRNA from total RNA of female fat body. It also hybridized with fat body RNA of normal prepupae and methoprene treated day 0 pupae but not with that of early fifth instars or solvent control pupae. The results indicate that the trace amounts of Vg found in prepupal stages are due to a weak expression of the Vg gene, which is stimulated by JH and repressed by 20‐HE. © 1994 Wiley‐Liss, Inc.