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Genes induced during the early developmental stages of the Cane Toad, Bufo (Chaunus) marinus.

CSIRO Entomology, Clunies Ross Street, GPO Box 1700, Canberra, ACT 2601, Australia.
Gene Expression Patterns (Impact Factor: 1.36). 08/2008; 8(6):424-32. DOI: 10.1016/j.gep.2008.04.005
Source: PubMed

ABSTRACT Metamorphosis, a critical stage in the development of toads and frogs, involves rapid levels of morphological change. In the current study, we have used microarray analysis to identify shifts in gene expression between tadpole and toadlet stages of the cane toad, Bufo (Chaunus) marinus. Here, we report on nine genes that show the greatest induction during metamorphosis; the gut-associated gastrokine and trefoil factor, blood components haemoglobins alpha/beta, apolipoprotein and serum albumin, a nasal gene olfactomedin, a lens gene gamma-crystallin, and a novel gene with low homology to frog harderin. We present both temporal and spatial expression patterns of these genes identified in developing and adult cane toads. This study extends our knowledge of the molecular basis of toad metamorphosis, and not only offers insights to the genes induced during the general remodelling that occurs but also reveals possible targets for control and manipulation of amphibian pest species, for example, the cane toad in Australia.

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    ABSTRACT: A major goal for understanding the role of thyroid hormone (TH) in development has been to identify genes regulated by TH in different tissues during frog metamorphosis. The exquisite dependence of metamorphosis on TH also provides a model to study TH endocrine disruption. To identify such TH-regulated genes and select biomarkers for TH endocrine disruption, global gene expression analyses in tadpoles using microarrays have been done in 21 studies, involving five frog species, seven organs, and four endocrine disrupting chemicals. As expected, each organ has a unique set of genes associated with its tissue-specific metamorphic outcome, and functions ascribed to many of these genes correspond to histological changes induced by TH. Also, the large number of transcription factors identified in microarrays is consistent with the molecular mechanisms of TH action. On the other hand, microarray analysis has also revealed interesting findings not predicted from previous morphological or molecular studies. Furthermore, endocrine disruption studies identified candidate biomarkers for TH disruption, and the mechanisms of action of several endocrine disrupting chemicals have been examined. The microarray studies described here have produced a wealth of data on gene expression that requires further functional studies to elucidate the roles of these genes in development and endocrine disruption.
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