Meeting Abstract
Thyroid hormones play numerous essential roles in vertebrate development. A century of research has demonstrated that these endocrine factors have numerous physiological and developmental functions. From cells to whole organisms, they participate in the regulation and coordination of many biological processes, and abnormal production of thyroid hormones underlies a variety of human disorders. Advances in molecular technology offer the opportunity to study the cellular and developmental functions of thyroid hormones in detail. To determine the mechanisms by which these hormones mediate development, we utilized a stable transgenic zebrafish line, Tg(tg:nVenus-2a-nfnB), that allowed us to conditionally ablate the thyroid follicles. We performed the ablation early in ontogeny and let the fish develop without thyroid hormones through adulthood. Focusing on poorly-understood post-metamorphic stages, we examined changes in various traits across ontogeny. We are analyzing body and facial shape, neuromasts of the lateral line, the olfactory organ, taste buds, eye, inner ear, fins, axial skeleton, scales, and adipose tissue at multiple developmental stages. In particular, we found that ossification and remodeling of both craniofacial and axial skeletons were highly dependent on thyroid hormones. Contrary to expectations, we found that thyroid hormones inhibited proliferation of superficial neuromasts in the head, but not along the body. These analyses provide a foundation for discovering thyroid hormone-mediated developmental mechanisms.
