Linked Life Data

10998636

Source:http://linkedlifedata.com/resource/pubmed/id/10998636

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2000-11-28
pubmed:abstractText
Thyroid hormone is presumed to play a role in initiating and/or orchestrating the postembryonic expression of the genes encoding isoforms of the myosin heavy chains (MHCs) that characterize the muscle fibres in an adult organism. The fact that the postembryonic development of a free-living amphibian tadpole takes place during its thyroid hormone-dependent metamorphosis has made the metamorphosing tadpole an ideal system for elucidating the molecular mechanism(s) by which this hormone affects these postembryonic changes. In this review, we summarize the results from recent studies focused on the postembryonic expression of the MHC genes in the skeletal muscles and hearts of metamorphosing anuran (Rana catesbeiana) tadpoles. The demonstration that mRNAs encoding at least five of the MHC isoforms present in the tadpole tail muscles are also present in the adult hind-limb muscles and that an mRNA encoding a cardiac-specific MHC isoform is present in the heart of both the tadpole and adult organism, rules out the possibility that thyroid hormone initiates the expression of these MHC genes. Instead, it seems more likely that this hormone acts by modulating the expression of one or more of the genes encoding these particular MHC isoforms. Whatever the case, the fact that sequence homology suggests that the five distinct skeletal muscle-specific MHCs are all "fast" isoforms raises the question of how these MHCs are distributed among the three different fibre types described for Rana. On the other hand, the possibility exists that the mRNAs for one or more of these fast MHC isoforms encode developmental isoforms that are present but not translated in the muscles of the tadpole and/or adult frog. Finally, an evaluation of the evolutionary relatedness of the R. catesbeiana MHCs to the MHCs in another species of Rana and to the MHCs in other vertebrates discloses, among other things, that the nucleotide sequence in the R. catesbeiana cardiac MHC isoform is more closely related to the chicken ventricular MHC isoform than it is to any of the other MHC isoforms examined.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1059-910X
pubmed:author
pubmed:copyrightInfo
Copyright 2000 Wiley-Liss, Inc.
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
50
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
458-72
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Postembryonic expression of the myosin heavy chain genes in the limb, tail, and heart muscles of metamorphosing amphibian tadpoles.
pubmed:affiliation
Department of Zoology, University of Western Ontario, London, Ontario, Canada N6A 5B7.
pubmed:publicationType
Journal Article, Review, Research Support, Non-U.S. Gov't