Article Abstract:
Investigations were directed at the pulse of the steroid hormone ecdysone, in Drosophila melanogaster, that activates the larval-to-adult metamorphosis. The hormone ensures the deterioration of larval tissues and the development of adult structures by stimulating imaginal tissues. The EcR gene encodes three ecdysone receptor isoforms (EcR-A, EcR-B1 and EcR-B2) that differ in their N-terminal areas but share DNA-and hormone-binding sites. At the start of metamorphosis, various ecdysone target tissues express varied isoform combinations in a fashion that concords with the assumption that varied combinations of the EcR isoforms are needed for the varied metamorphic reactions of these tissues.
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Article Abstract:
Metamorphosis in Drosophila is directed by the steroid hormone ecdysone. The action of ecdysone is mediated via heterodymeric receptors encoded by the gene EcR. There are three isoforms of this receptors encoded by EcR-A, EcR-B1 and EcR-B2. Two mutations on the EcR gene have been identified and mapped. One of these mutations uncouples metamorphosis and the other, which disrupts ligand- and DNA-binding domains, is lethal. The results of transgenic expression of the mutant genes in Drosophila salivary glands are presented.
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Article Abstract:
Research was conducted to study the molecular isolation of zebrafish one-eyed pinhead (oep) as an epidermal growth factor-related ligand during vertebrate gastrulation. DNA polymorphisms were assayed to measure the genetic distance between polymerase chain reaction markers and the oep locus. Results indicated that loss of oep function interfered the development of prechordal plate, ventral neurectoderm, endoderm and heart.
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