Ecdysteroids regulate yolk protein uptake by Drosophila melanogaster oocytes

Richard, David; Watkins, Noel L; Serafin, Robert; Gilbert, Lawrence I.

doi:10.1016/s0022-1910(98)00020-1

Cited by 133 publications

(74 citation statements)

References 36 publications

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“…During the reproductive phase of the fruit-fly, JH controls the early synthesis of yolk proteins (YPs) by the fat bodies and the ovarian follicle cells, and YPs are taken up by the developing egg chambers. JH also induces the ovaries to produce 20-hydroxyecdysone (20-OH Ecd), which sustains late vitellogenesis, by inducing the synthesis and uptake of YPs by the fat bodies [72][73][74][75]. However, an excess of 20-OH Ecd induces apoptosis in nurse cells of stage 9 egg chambers, during early vitellogenesis.…”

Section: Larval and Adult Diapause Are Regulated By Jh And Ecdmentioning

confidence: 99%

The hormonal and circadian basis for insect photoperiodic timing

2011

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Edited by Martha Merrow and Michael BrunnerKeywords: Insects Photoperiodism Diapause Endocrine axis Circadian clock Clock genes a b s t r a c t Daylength perception in temperate zones is a critical feature of insect life histories, and leads to developmental changes for resisting unfavourable seasons. The role of the neuroendocrine axis in the photoperiodic response of insects is discussed in relation to the key organs and molecules that are involved. We also discuss the controversial issue of the possible involvement of the circadian clock in photoperiodicity. Drosophila melanogaster has a shallow photoperiodic response that leads to reproductive arrest in adults, yet the unrivalled molecular genetic toolkit available for this model insect should allow the systematic molecular and neurobiological dissection of this complex phenotype.

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Section: Larval and Adult Diapause Are Regulated By Jh And Ecdmentioning

confidence: 99%

The hormonal and circadian basis for insect photoperiodic timing

2011

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“…In diapausing female adults, oogenesis is arrested shortly before vitellogenesis but can be relieved by the application of 20-hydroxyecdysone (20E) (Richard et al, 1998). Based on this and other observations, it was proposed that in the early stages following adult eclosion, ecdysteroids derived from the ovary or from other sources (Bownes, 1989) stimulate YP synthesis in the fat body as well as YP uptake by the oocyte (Richard et al, 1998).…”

Section: The Transition From Previtellogenesis To Vitellogenesismentioning

confidence: 99%

Vitellogenesis and Post-Vitellogenic Maturation of the Insect Ovarian Follicle

Swevers

2005

Comprehensive Molecular Insect Science

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“…Juvenile hormone (JH), in particular, seems to play a key role in various insects in releasing the oocyte from this block (reviewed by Raikhel and Dhadialla, 1992). Recent work also suggests that ecdysteroids may be involved in the inception of vitellogenesis (Richard et al, 1998); however, the cellular mechanisms underlying the initiation of yolk uptake are unresolved. Thus, in addition to the endocytic profile, we were interested in the regulation of yl during oogenesis.…”

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confidence: 99%

Regulation of the Vitellogenin Receptor duringDrosophila melanogasterOogenesis

Schonbaum

Perrino

Mahowald

2000

MBoC

103

115

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In many insects, development of the oocyte arrests temporarily just before vitellogenesis, the period when vitellogenins (yolk proteins) accumulate in the oocyte. Following hormonal and environmental cues, development of the oocyte resumes, and endocytosis of vitellogenins begins. An essential component of yolk uptake is the vitellogenin receptor. In this report, we describe the ovarian expression pattern and subcellular localization of the mRNA and protein encoded by the Drosophila melanogaster vitellogenin receptor gene yolkless (yl). yl RNA and protein are both expressed very early during the development of the oocyte, long before vitellogenesis begins. RNA in situ hybridization and lacZ reporter analyses show that yl RNA is synthesized by the germ line nurse cells and then transported to the oocyte. Yl protein is evenly distributed throughout the oocyte during the previtellogenic stages of oogenesis, demonstrating that the failure to take up yolk in these early stage oocyte is not due to the absence of the receptor. The transition to the vitellogenic stages is marked by the accumulation of yolk via clathrin-coated vesicles. After this transition, yolk protein receptor levels increase markedly at the cortex of the egg. Consistent with its role in yolk uptake, immunogold labeling of the receptor reveals Yl in endocytic structures at the cortex of wild-type vitellogenic oocytes. In addition, shortly after the inception of yolk uptake, we find multivesicular bodies where the yolk and receptor are distinctly partitioned. By the end of vitellogenesis, the receptor localizes predominantly to the cortex of the oocyte. However, during oogenesis in yl mutants that express full-length protein yet fail to incorporate yolk proteins, the receptor remains evenly distributed throughout the oocyte. INTRODUCTIONThe magnitude of yolk uptake into the oocyte during vitellogenesis suggests a heavy involvement of the endocytic machinery; indeed, the clathrin-coated vesicle was originally described in the vitellogenic mosquito oocyte (Roth and Porter, 1964). Because the morphological features are so striking, descriptions of vitellogenesis have been made in a broad range of oviparous species, including birds (Perry and Gilbert, 1979;Perry et al., 1984), frogs (Opresko and Wiley, 1987;Wall and Patel, 1987), fish (reviewed by Wallace andSelman, 1990), and insects (Cummings andMahowald, 1972; Giorgi and Jacob, 1977a,b;Raikhel, 1984;van Antwerpen et al., 1993) (reviewed by Raikhel and Dhadialla, 1992). In several cases, immunocytochemical and ultrastructural studies using labeled yolk protein precursors or fluid phase markers have followed the fate of the proteins as they are sorted to the yolk platelets (Giorgi and Jacob, 1977a;Raikhel, 1984;Busson et al., 1989). The initial steps in the yolk uptake pathway are similar to those described for general receptor-mediated endocytosis (Goldstein et al., 1985;Mukherjee et al., 1997). Vitellogenins (Vgs) are taken up through clathrin-coated pits, and they accumulate initially in vesiculotubul...

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Ecdysteroids regulate yolk protein uptake by Drosophila melanogaster oocytes

Cited by 133 publications

References 36 publications

The hormonal and circadian basis for insect photoperiodic timing

The hormonal and circadian basis for insect photoperiodic timing

Vitellogenesis and Post-Vitellogenic Maturation of the Insect Ovarian Follicle

Regulation of the Vitellogenin Receptor duringDrosophila melanogasterOogenesis

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