Thyroid hormone controls the development of connections between the spinal cord and limbs during Xenopus laevis metamorphosis.

TitleThyroid hormone controls the development of connections between the spinal cord and limbs during Xenopus laevis metamorphosis.
Publication TypeJournal Article
Year of Publication2004
AuthorsMarsh-Armstrong N, Cai L, Brown DD
JournalProceedings of the National Academy of Sciences of the United States of America
Volume101
Issue1
Pagination165-70
Date Published2004 Jan 6
Abstract

During premetamorphic stages, Xenopus laevis tadpoles expressing either a dominant-negative thyroid hormone (TH) receptor or a type-III iodothyronine deiodinase transgene in the nervous system have reduced TH-induced proliferation in the spinal cord and produce fewer hindlimb-innervating motorneurons. During prometamorphic stages, innervation of the hindlimbs is reduced, and few functional neuromuscular connections are formed. By metamorphic climax, limb movement is impaired, ranging from uncoordinated leg swimming to complete quadriplegia. This phenotype is due to transgene action in the tadpole spinal cord. The requirement of TH for neurogenesis during premetamorphosis is the earliest TH-regulated process reported to date in the sequence of metamorphic changes in anurans. The muscle formed during limb growth was previously shown to be a direct target of TH control. Here, we show that the same is true of the development of spinal cord cells that innervate the limbs.

Alternate JournalProc. Natl. Acad. Sci. U.S.A.