Literaturdatenbank
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Jeyasuria, P., & Place, A. R. (1997). Temperature-dependent aromatase expression in developing diamondback terrapin (malaclemys terrapin) embryos. The Journal of Steroid Biochemistry and Molecular Biology, 61(3), 415–425.
Added by: Admin (17 Aug 2008 18:54:49 UTC) |
| Resource type: Journal Article BibTeX citation key: Jeyasuria1997 View all bibliographic details  |
Categories: General Keywords: Emydidae, Malaclemys, Malaclemys terrapin, Schildkröten = turtles + tortoises, Zeitigung = incubation Creators: Jeyasuria, Place Collection: The Journal of Steroid Biochemistry and Molecular Biology |
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| Abstract |
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In the diamondback terrapin, Malaclemys terrapin, males hatch at incubation temperatures below 28degree C whereas females hatch at temperatures above 30degree C. When estrogen is applied to the eggs at male temperatures early in development, females are produced. These data suggest that the enzyme necessary for estrogen synthesis (CYP19, aromatase) in the developing gonad plays a critical role in sex determination in these vertebrates. Accordingly, we have begun an examination of the role and regulation of the aromatase gene in sex determination in the diamond back terrapin, Malaclemys terrapin. We have obtained full-length cDNAs for terrapin ovarian aromatase. Using reverse transcription-polymerase chain reaction (RT-PCR) on mRNA from various tissues we have determined that aromatase is expressed in the female brain and ovary, whereas it is only expressed in the brain of the male. Brain expression of aromatase occurs before stage 15, the beginning of the temperature-dependent sex determining period. Ovarian expression occurs sometime later. To quantify expression levels, we have developed a competitive RT-PCR technique to study the ontogeny of aromatase transcript levels throughout development. The sensitivity of our assay (0.001-10 atmol of transcript) permits us to analyse individual embryonic adrenal/kidney/gonadal complexes without pooling samples. Female hatchlings (stage 26) brains express higher aromatase mRNA levels than male brains (381 +- 80 vs 202 +- 85 atmol/mug RNA, respectively). Similarly, ovaries express significantly higher aromatase mRNA levels than hatchling testes (352 +- 117 vs <0.001 atmol/mug RNA, respectively).
Added by: Admin |