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OOCYTE ENVELOPE PROTEINS AND VITELLOGENIN IN MALE SHEEPHEAD MINNOW EXPOSED TO ESTRADIOL
Citation:
Gillis, L. D., I. Knoebl, N D. Denslow, AND L C. Folmar. OOCYTE ENVELOPE PROTEINS AND VITELLOGENIN IN MALE SHEEPHEAD MINNOW EXPOSED TO ESTRADIOL. Presented at SETAC 22 Annual Meeting, Baltimore, MD, November 11-15, 2001.
Description:
Oocyte Envelope Proteins and Vitellogenin Expression in Male Sheepshead Minnows Exposed to Estradiol (Abstract). To be presented at the 22nd Annual Meeting of the Society of Environmental Toxicology and Chemistry: Changing Environmental Awareness: Societal Concerns and Scientific Responses, 11-15 November 2001, Baltimore, MD. 1 p. (ERL,GB R855).
n female oviparous vertebrates, the formation of the protective egg envelope occurs during oogenesis when the constitutent structural proteins are deposited between the plasma membrane of the oocyte and the surrounding follicle cells. This envelope consists of one or two thin outer layers and a thick inner layer. In teleosts, three to four proteins contribute to the formation of the thick inner layer of the oocyte envelope. Recent studies have shown a hepatic origin for these structural proteins in some species of fish. Importantly, the expression of these proteins during oogenesis appears to precede that of vitellogenin, a know biomarker of
estrogen exposure in male fish. We have examined the structural proteins of the egg envelope in the sheepshead minnow to determine their possible use as biomarker(s) of estrogen and estrogen mimic exposures in the sheepshead minnow (SHM), Cyprinodon variegatus. Using sequenced cDNA fragments originally determined from differential display experiments defining up-regulated messages in the liver of the SHM following injections of estradiol-17b(E2), we have cloned the cDNA for these structural proteins. The resultant sequence data were used as probes to analyze the comparative expression of the transcripts for these proteins over a period of zero to 48 hours in adult, male SHM exposed to 100 ng/L estradiol in a
flow-through aquatic exposure. We included probes complementary to vitellogenin transcripts for the envelope proteins relative to a known biomarker of estrogen exposure.