Administration of estradiol-17@ to male Xenopus laevis induces synthesis and secretion by the liver of the egg yolk precursor protein vitellogenin. RNA extracted from livers of estradiol-17@-treated Xenopus Zaeuis directs the synthesis of the entire 200,000-dalton vitellogenin monomer in a cell-free protein synthesizing system derived from rabbit reticulocytes. Vitellogenin synthesized in uitro...

The caste-specific regulation of vitellogenin synthesis in the honeybee represents a problem with many yet unresolved details. We carried out experiments to determine when levels of vitellogenin are first detected in hemolymph of female castes of Apis mellifera, and whether juvenile hormone and ecdysteroids modulate this process. Vitellogenin levels were measured in hemolymph using immunologica...

The vitellogenic cycle of the lubber grasshopper (Romalea microptera) was studied by measuring levels of juvenile hormone (JH III), vitellogenin, and vitellogenin-mRNA through the first oviposition cycle. JH III and vitellogenin were measured by radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA), respectively. To measure vitellogenin-mRNA, a partial (753 bp) cDNA fragment of v...

A partial cDNA clone of the vitellogenin gene from the cockroach Blattella germanica has been isolated from a cDNA expression library using an anti-vitellin-vitellogenin antiserum probe. The analysis of cDNA inserts gave a sequence of 2,645 nucleotides corresponding to the 3' region. The deduced amino acid sequence is 825 residues long and is similar to the homologous portion of the vitellogeni...

Vitellogenin, an egg-yolk protein precursor common to oviparous animals, is found abundantly in honeybee workers - a caste of helpers that do not usually lay eggs. Instead, honeybee vitellogenin (180 kDa) participates in processes other than reproduction: it influences hormone signaling, food-related behavior, immunity, stress resistance and longevity. The molecular basis of these functions is ...

Vitellogenin is a yolk precursor protein in most oviparous females. In the advanced eusocial honeybee, Apis mellifera (Hymenoptera: Apidae), vitellogenin has recently attracted much interest as this protein, in addition to a classical function in oocyte development in the reproductive queen caste, has evolved functions in the facultatively sterile female worker caste not documented in other spe...

The relationship between blood protein (vitellogenin) incorporation and nuclear maturation was studied in individual amphibian oocytes after in vitro exposure to desoxycorticosterone acetate (DOCA). Isolated Rana pipiens oocytes were incubated in vitro with radioactively labeled oocyte yolk precursor ([(3)H]vitellogenin) obtained from estrogenized Xenopus laevis. Incorporation of labeled vitell...

We aimed to elucidate why cockroaches do not produce vitellogenin in immature stages, by studying the appearance of vitellogenin mRNA in larvae of Blattella germanica. Treatment of female larvae in any of the last three instars with 1 microg of juvenile hormone (JH) III induces vitellogenin gene transcription, which indicates that the fat body is competent to transcribe vitellogenin at least fr...

Macromolecules of vitellogenin were sequestered by Xenopus laevis oocytes 20-50 times (on a molar basis) more rapidly than other proteins tested. Selectivity for vitellogenin did not appear to involve molecular size or charge. The Km for vitellogenin incorporation was at least several orders of magnitude less than that for bovine serum albumin (BSA). At concentrations less than 10 mg-ml-1, BSA ...

The purpose of this study was to develop an immunoassay for vitellogenin in Morelet's crocodile (Crocodylus moreletii). Blood was collected from wild-caught crocodiles in Belize. Plasma samples from adult females taken during the breeding season were used for vitellogenin purification and samples from adult males were used for comparison. No differences were detected between males and females f...