Thyroid Hormone Receptor Genes of Neotenic Amphibians

Safi, Rachid; Bégué, Agnès; Hänni, Catherine; Stéhelin, D; Tata, Jamshed R.; Laudet, Vincent

doi:10.1007/pl00006182

Cited by 35 publications

(18 citation statements)

References 42 publications

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“…Obligatorily neotenic species like Necturus are unable to complete metamorphosis in that the external gills and tail fins of these animals are resistant to TH even though they have fully developed limbs. Interestingly, they express TR␣ in those tissues, but there is no detectable baseline or inducible TR␤ message even though an apparently normal TR␤ gene exists in the genome (34).…”

Section: Discussionmentioning

confidence: 99%

Induction of Larval Tissue Resorption in Xenopus laevis Tadpoles by the Thyroid Hormone Receptor Agonist GC-1

Furlow

Yang

Hsu

et al. 2004

Journal of Biological Chemistry

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A major challenge in understanding nuclear hormone receptor function is to determine how the same ligand can cause very different tissue-specific responses. Tissue specificity may result from the presence of more than one receptor subtype arising from multiple receptor genes or alternative splicing. Recently, high affinity analogs of nuclear receptor ligands have been synthesized that show subtype selectivity. These analogs can greatly facilitate the study of receptor subtype-specific functions in organisms where mutational analysis is problematic or where it is desirable for receptors to be expressed in their normal physiological contexts. We describe here the effects of the synthetic thyroid hormone analog GC-1 on the metamorphosis of the frog Xenopus laevis. The most potent natural thyroid hormone, 3,5,3-triidothyronine or T3, shows similar binding affinity and transactivation dose-response curves for both thyroid hormone receptor isotypes, designated TR␣ and TR␤. GC-1, however, binds to and activates TR␤ at least an order of magnitude better than it does TR␣. GC-1 efficiently induces death and resorption of premetamorphic tadpole tissues such as the gills and the tail, two tissues that strongly induce thyroid hormone receptor ␤ during metamorphosis. GC-1 has less effect on the growth of adult tissues such as the hindlimbs, which express high TR␣ levels. The effectiveness of GC-1 in inducing tail resorption and tail gene expression correlates with increasing TR␤ levels. These results illustrate the utility of subtype selective ligands as probes of nuclear receptor function in vivo.

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Section: Discussionmentioning

confidence: 99%

Induction of Larval Tissue Resorption in Xenopus laevis Tadpoles by the Thyroid Hormone Receptor Agonist GC-1

Furlow

Yang

Hsu

et al. 2004

Journal of Biological Chemistry

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“…Thus, the complete cycle was as follows: 94 C, 1 min; hybridization at 55-37 C, 1 min; 72 C, 1 min; 40 cycles. To avoid contamination, all of the RT-PCR reactions as well as RNA extraction were conducted in a special nucleic-acidfree room under positive air pressure and using specific reagents (Safi et al 1997, Hänni et al 1994. For each pair of primers used, we prepared a control reaction (without DNA) to check that our PCR reactions were not contaminated (in order to avoid spurious amplification of TRs from mammals routinely used in our laboratory).…”

Section: Ti(a/g)tg(c/t)ttic(g/t)g(a/t)a(a/g)tt(a/g)atmentioning

confidence: 99%

Molecular cloning and characterization of thyroid hormone receptors in teleost fish

Marchand¹,

Safi²,

Escrivà³

et al. 2001

Journal of Molecular Endocrinology

107

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Thyroid hormones are pleiotropic factors important for many developmental and physiological functions in vertebrates. Their effects are mediated by two specific receptors (TR and TR ) which are members of the nuclear hormone receptor superfamily. To clarify the function of these receptors, our laboratory has started a comparative study of their role in teleost fish. This type of approach has been hampered by the isolation of specific clones for each fish species studied. In this report, we describe an efficient reverse transcription/PCR procedure that allows the isolation of large fragments corresponding to TR and TR of a wide range of teleost fish. Phylogenetic analysis of these receptors revealed a placement consistent with their origin, sequences from teleost fish being clearly monophyletic for both TR and TR . Interestingly, this approach allowed us to isolate (from tilapia and salmon) several new TR or TR isoforms resulting from alternative splicing. These isoforms correspond to expressed transcripts and thus may have an important physiological function. In addition, we isolated a cDNA encoding TR in the Atlantic salmon (Salmo salar) encoding a functional thyroid hormone receptor which binds specific thyroid hormone response elements and regulates transcription in response to thyroid hormones.

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“…The reason for failure to metamorphose is absence of thyroid stimulating hormone (TSH), hence no thyroxine production, a condition ameliorated by adding TSH or T 3 to aquarium water with the startling result of metamorphosis into an adult land-dwelling form never seen naturally resembling an "ordinary" tiger salamander [Safi et al, 1997[Safi et al, , 2004Laudet, 2011]. In other words, TSH loss was recent enough so that metamorphosing capacity and downstream metamorphosing genes remained intact.…”

Section: Reversion In Sex Developmentmentioning

confidence: 99%

Annals of morphology. Atavisms: Phylogenetic lazarus?

Zanni

Opitz

2013

American J of Med Genetics Pt A

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Dedication: with highest respect and affection to Prof. Giovanni Neri on the eve of his official administrative retirement as Chair of the Institute of Medical Genetics of the Università Cattolica of Rome for leadership in medical genetics and medical science and friendship for decades. The concept “atavism,” reversion, throwback, Rückschlag remains an epistemological challenge in biology; unwise or implausible over‐interpretation of a given structure as such has led some to almost total skepticism as to its existence. Originating in botany in the 18th century it became applied to zoology (and humans) with increasing frequency over the last two centuries such that the very concept became widely discredited. Presently, atavisms have acquired a new life and reconsideration given certain reasonable criteria, including: Homology of structure of the postulated atavism to that of ancestral fossils or collateral species with plausible soft tissue reconstructions taking into account relationships of parts, obvious sites of origin and insertion of muscles, vascular channels, etc. Most parsimonious, plausible phylogenetic assumptions. Evident rudimentary or vestigial anatomical state in prior generations or in morphogenesis of a given organism. Developmental instability in prior generations, that is, some closely related species facultatively with or without the trait. Genetic identity or phylogenomic similarity inferred in ancestors and corroborated in more or less closely related species. Fluctuating asymmetry may be the basis for the striking evolutionary diversification and common atavisms in limbs; however, strong selection and developmental constraints would make atavisms in, for example, cardiac or CNS development less likely.Thus, purported atavisms must be examined critically in light of the above criteria. © 2013 Wiley Periodicals, Inc.

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Thyroid Hormone Receptor Genes of Neotenic Amphibians

Cited by 35 publications

References 42 publications

Induction of Larval Tissue Resorption in Xenopus laevis Tadpoles by the Thyroid Hormone Receptor Agonist GC-1

Induction of Larval Tissue Resorption in Xenopus laevis Tadpoles by the Thyroid Hormone Receptor Agonist GC-1

Molecular cloning and characterization of thyroid hormone receptors in teleost fish

Annals of morphology. Atavisms: Phylogenetic lazarus?

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