A model of transcriptional and morphological changes during thyroid hormone-induced metamorphosis of the axolotl

Page, Robert B.; Monaghan, James R.; Walker, John; Voss, S. Randal

doi:10.1016/j.ygcen.2009.03.001

Cited by 45 publications

(32 citation statements)

References 58 publications

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“…Most of what is known has been derived from work with frogs, principally Xenopus and Rana (e.g., Buchholz et al 2007), although recent work with ambystomatid salamanders (especially the axolotl, Ambystoma mexicanum ) has also added to this information (Boorse and Denver 2002; Page et al 2008, 2009). T 3 is the more active form that regulates transcription and morphogenesis; the conversion of T 4 to the more active T 3 is controlled by deiodinases in the cytoplasm of target tissues.…”

Section: Is the Metamorphic Response To Thyroid Hormones And Corticosmentioning

confidence: 99%

How Metamorphosis Is Different in Plethodontids: Larval Life History Perspectives on Life-Cycle Evolution

2017

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Plethodontid salamanders exhibit biphasic, larval form paedomorphic, and direct developing life cycles. This diversity of developmental strategies exceeds that of any other family of terrestrial vertebrate. Here we compare patterns of larval development among the three divergent lineages of biphasic plethodontids and other salamanders. We discuss how patterns of life-cycle evolution and larval ecology might have produced a wide array of larval life histories. Compared with many other salamanders, most larval plethodontids have relatively slow growth rates and sometimes exceptionally long larval periods (up to 60 mo). Recent phylogenetic analyses of life-cycle evolution indicate that ancestral plethodontids were likely direct developers. If true, then biphasic and paedomorphic lineages might have been independently derived through different developmental mechanisms. Furthermore, biphasic plethodontids largely colonized stream habitats, which tend to have lower productivity than seasonally ephemeral ponds. Consistent with this, plethodontid larvae grow very slowly, and metamorphic timing does not appear to be strongly affected by growth history. On the basis of this, we speculate that feeding schedules and stress hormones might play a comparatively reduced role in governing the timing of metamorphosis of stream-dwelling salamanders, particularly plethodontids.

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Section: Is the Metamorphic Response To Thyroid Hormones And Corticosmentioning

confidence: 99%

How Metamorphosis Is Different in Plethodontids: Larval Life History Perspectives on Life-Cycle Evolution

2017

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“…We have used a variety of approaches in previous studies to examine gene expression change as a function of time, including t tests, multifactor ANOVA, repeated measures ANOVA, parametric and Bayesian linear and nonlinear modeling, piecewise regression, and clustering (e.g., Huggins et al 2012; Li et al 2004; Liu et al 2005; Page et al 2007, 2008, 2009, 2010, 2013; Monaghan et al 2007, 2009, 2012; Athippozhy et al 2014). These approaches are proven to be effective within the context of experimental designs that sample relatively few points in time.…”

Section: Introductionmentioning

confidence: 99%

Gene expression during the first 28 days of axolotl limb regeneration I: Experimental design and global analysis of gene expression

et al. 2015

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While it is appreciated that global gene expression analyses can provide novel insights about complex biological processes, experiments are generally insufficiently powered to achieve this goal. Here we report the results of a robust microarray experiment of axolotl forelimb regeneration. At each of 20 post-amputation time points, we estimated gene expression for 10 replicate RNA samples that were isolated from 1 mm of heterogeneous tissue collected from the distal limb tip. We show that the limb transcription program diverges progressively with time from the non-injured state, and divergence among time adjacent samples is mostly gradual. However, punctuated episodes of transcription were identified for five intervals of time, with four of these coinciding with well-described stages of limb regeneration—amputation, early bud, late bud, and pallet. The results suggest that regeneration is highly temporally structured and regulated by mechanisms that function within narrow windows of time to coordinate transcription within and across cell types of the regenerating limb. Our results provide an integrative framework for hypothesis generation using this complex and highly informative data set.

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“…the primary endocrine regulator of metamorphosis (Buchholz 63 et al, 2011;Page et al, 2009;Safi et al, 2006;Elinson, 2013). 64 Like most endocrine axes, the thyroid axis consists of a series of 65 central regulators that mediate the production and release of TH 66 from the thyroid gland and peripheral regulators that mediate tis-67 sue-specific responses to circulating hormone (Buchholz et al, 68 2011).…”

Section: Introductionmentioning

confidence: 99%

Development of neuroendocrine components of the thyroid axis in the direct-developing frog Eleutherodactylus coqui: Formation of the median eminence and onset of pituitary TSH production

Jennings

Evans

Howard

2015

General and Comparative Endocrinology

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Direct-developing frogs lack, wholly or in part, a wide range of larval features found in metamorphosing species and form adult-specific features precociously, during embryogenesis. Most information on thyroid regulation of direct development relies on hormone manipulations; the ontogeny of many thyroid axis components has not been fully described. This analysis examines differentiation of the median eminence of the hypothalamus and production of thyroid-stimulating hormone (TSH) by the pituitary of the direct-developing frog Eleutherodactylus coqui. The median eminence is established two-thirds of the way through embryogenesis. Cells immunoreactive to human TSHβ antibodies are first detected during embryogenesis and quantitative changes in TSHβ-IR cells resemble those in metamorphosing amphibians. Formation of the median eminence of the hypothalamus and TSHβ production by the pituitary precede or coincide with morphological changes during embryogenesis that occur during metamorphosis in biphasic anurans. Thus, while the onset of neuroendocrine regulation has changed during the evolution of direct development, it is likely that these thyroid axis components still mediate the formation of adult features.

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A model of transcriptional and morphological changes during thyroid hormone-induced metamorphosis of the axolotl

Cited by 45 publications

References 58 publications

How Metamorphosis Is Different in Plethodontids: Larval Life History Perspectives on Life-Cycle Evolution

How Metamorphosis Is Different in Plethodontids: Larval Life History Perspectives on Life-Cycle Evolution

Gene expression during the first 28 days of axolotl limb regeneration I: Experimental design and global analysis of gene expression

Development of neuroendocrine components of the thyroid axis in the direct-developing frog Eleutherodactylus coqui: Formation of the median eminence and onset of pituitary TSH production

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