Molecular Cloning and Expression of Thyroid Hormone Receptor Alpha during Salmonid Development

Jones, Iwan; Rogers, Sarah A.; Kille, Peter; Sweeney, Glen E.

doi:10.1006/gcen.2001.7745

Cited by 40 publications

(22 citation statements)

References 32 publications

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“…After several washes in PBS, the sections were blocked (10% normal goat serum in 0.08 M PBS) for 30 min and incubated in primary antibody, monoclonal rabbit anti-TRa1 (1:100; Affinity BioReagents), for 2 hr at room temperature. This antibody recognizes part of the rainbow trout TRa transactivation motif (amino acids 212-218; GenBank accession number AAD30058), a highly conserved, integral component of the TRa ligand-binding domain (Jones et al, 2002). The specificity of this antibody for the TRa isoform was confirmed previously (Mader and Cameron, 2006).…”

Section: Tra Immunohistochemistrysupporting

confidence: 62%

“…Its levels peak during embryogenesis, at hatching (alevin stage), and during smoltification, a physiological transformation that enables the freshwater juvenile (parr stage) to survive in saltwater (smolt stage) throughout its adult life (Greenblatt et al, 1989;Novales Flamarique, 2005). TRa expression parallels these surges in thyroid hormone; semiquantitative real-time polymerase chain reaction (RT-PCR) analyses in embryonic and early juvenile rainbow trout have detected TRa transcripts at relatively high levels during embryogenesis, hatching, and at full yolk sac absorption (Jones et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

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Thyroid hormone accelerates opsin expression during early photoreceptor differentiation and induces opsin switching in differentiated TRα‐expressing cones of the salmonid retina

Gan

Flamarique

2010

Developmental Dynamics

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Thyroid hormone and its receptors (TRs) regulate photoreceptor differentiation and visual pigment protein (opsin) expression in the retinas of several vertebrates, including rodents and fish. In some of these animals, opsin expression can arise through switches within differentiated cone photoreceptors. In salmonid fishes, single cones express ultraviolet (SWS1) opsin during embryonic development and switch to blue (SWS2) opsin as the fishes grow. It is unknown whether thyroid hormone regulates opsin expression during early cone differentiation and acts through TRs to induce opsin switches in differentiated cones of the salmonid retina. Using in situ hybridization, we characterized the spatiotemporal dynamics of opsin expression and switching in embryos treated with exogenous thyroid hormone or propylthiouracil (PTU), a pharmacological inhibitor of thyroid hormone synthesis. We combined immunohistochemistry with in situ hybridization to map TRa expression with respect to cones undergoing the opsin switch in older juvenile fish. Thyroid hormone accelerated opsin expression in differentiating cones and induced the opsin switch in differentiated single cones, whereas PTU repressed the opsin switch. TRa was not detected in differentiating photoreceptors as opsin expression initiated, but was later expressed in differentiated single cones before the onset of the opsin switch. TRa expression exhibited a dynamic dorsoventral distribution that paralleled the progression of the opsin switch. Together, our results show that thyroid hormone is required for opsin switching in the retina of salmonid fishes and suggest that TRa may be involved in regulating this phenomenon. Developmental Dynamics 239:2700-2713,

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Section: Tra Immunohistochemistrysupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Thyroid hormone accelerates opsin expression during early photoreceptor differentiation and induces opsin switching in differentiated TRα‐expressing cones of the salmonid retina

Gan

Flamarique

2010

Developmental Dynamics

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“…T 3 concentrations in fertilized eggs have been reported as high as 52·ng·g -1 body mass for salmonids (Mylonas et al, 1994), and maternal thyroid receptor transcripts have recently been identified in developing eggs and alevins (Jones et al, 2002). In addition, fluctuations in thyroid hormone have been linked to both hatching and emergence of fry from the gravel streambed Dickhoff and Sullivan, 1987;Leatherland et al, 1989;Hirano, 1987, 1989).…”

Section: Identity Of the Proliferating Cellsmentioning

confidence: 99%

Evidence that thyroid hormone induces olfactory cellular proliferation in salmon during a sensitive period for imprinting

Lema

Nevitt

2004

Journal of Experimental Biology

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Salmon have long been known to imprint and home to natal stream odors, yet the mechanisms driving olfactory imprinting remain obscure. The timing of imprinting is associated with elevations in plasma thyroid hormone levels, with possible effects on growth and proliferation of the peripheral olfactory system. Here, we begin to test this idea by determining whether experimentally elevated plasma levels of 3,5,3′-triiodothyronine (T 3) influence cell proliferation as detected by the 5-bromo-2′-deoxyuridine (BrdU) cell birth-dating technique in the olfactory epithelium of juvenile coho salmon (Oncorhynchus kisutch). We also explore how natural fluctuations in thyroxine (T4) relate to proliferation in the epithelium during the parr-smolt transformation. In both studies, we found that BrdU labeled both single and clusters of mitotic cells. The total number of BrdU-labeled cells in the olfactory epithelium was significantly greater in fish with artificially elevated T3 compared with placebo controls. This difference in proliferation was restricted to the basal region of the olfactory epithelium, where multipotent progenitor cells differentiate into olfactory receptor neurons. The distributions of mitotic cluster sizes differed significantly from a Poisson distribution for both T 3 and placebo treatments, suggesting that proliferation tends to be non-random. Over the course of the parr-smolt transformation, changes in the density of BrdU cells showed a positive relationship with natural fluctuations in plasma T4. This relationship suggests that even small changes in thyroid activity can stimulate the proliferation of neural progenitor cells in the salmon epithelium. Taken together, our results establish a link between the thyroid hormone axis and measurable anatomical changes in the peripheral olfactory system.

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“…Beyond anuran metamorphosis, thyroid hormone has been implicated in a wide range of important biological processes in organisms that lack an available genetic approach. These include direct and indirect development of amphibians and fish (28 -31), the control of photoperiodism in seasonally breeding birds (32), and smoltification of salmonids (33,34), all of which can be explored in more mechanistic detail using NH-3. Finally, our results clearly demonstrate the degree of structural and functional relatedness between the mammalian and amphibian TRs and further underscore the usefulness of the amphibian model for identifying biologically active nuclear receptor ligands.…”

Section: Co-activator Recruitment By the Trs Is Inhibited By Nh-3-mentioning

confidence: 99%

A Thyroid Hormone Antagonist That Inhibits Thyroid Hormone Action in Vivo

Lim

Nguyen

Yang

et al. 2002

Journal of Biological Chemistry

104

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We have characterized the newly developed thyroid hormone antagonist NH-3 in both cell culture and in vivo model systems. NH-3 binds Xenopus laevis thyroid hormone receptors directly in vitro and induces a conformation distinct from agonist-bound receptors. Transcriptional activation of a thyroid hormone response element-containing reporter gene is strongly inhibited by NH-3 in a dose-dependent manner. In addition, NH-3 prevents X. laevis thyroid hormone receptors from binding to the p160 family of co-activators GRIP-1 and SRC-1 in a two-hybrid assay. To assess the potency of the compound in vivo, we used induced and spontaneous X. laevis tadpole metamorphosis, a thyroid hormone-dependent developmental process. NH-3 inhibits thyroid hormone-induced morphological changes in a dose-dependent manner and inhibits the up-regulation of endogenous thyroid hormone-responsive genes. Spontaneous metamorphosis is efficiently and reversibly arrested by NH-3 with at least the same effectiveness as the thyroid hormone synthesis inhibitor methimazole. Therefore, NH-3 is the first thyroid hormone antagonist to demonstrate potent inhibition of thyroid hormone action in both cell culture-and whole animal-based assays.

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Molecular Cloning and Expression of Thyroid Hormone Receptor Alpha during Salmonid Development

Cited by 40 publications

References 32 publications

Thyroid hormone accelerates opsin expression during early photoreceptor differentiation and induces opsin switching in differentiated TRα‐expressing cones of the salmonid retina

Thyroid hormone accelerates opsin expression during early photoreceptor differentiation and induces opsin switching in differentiated TRα‐expressing cones of the salmonid retina

Evidence that thyroid hormone induces olfactory cellular proliferation in salmon during a sensitive period for imprinting

A Thyroid Hormone Antagonist That Inhibits Thyroid Hormone Action in Vivo

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