Biomaterial Database

Postembryonic expression of the myosin heavy chain genes in the limb, tail, and heart muscles of metamorphosing amphibian tadpoles. 2000

F V Gauthier, and M A Qadir, and P A Merrifield, and B G Atkinson

Department of Zoology, University of Western Ontario, London, Ontario, Canada N6A 5B7.

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.

UI	MeSH Term	Description	Entries
D008675	Metamorphosis, Biological	Profound physical changes during maturation of living organisms from the immature forms to the adult forms, such as from TADPOLES to frogs; caterpillars to BUTTERFLIES.	Biological Metamorphosis,Biological Metamorphoses,Metamorphoses, Biological
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009206	Myocardium	The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.	Muscle, Cardiac,Muscle, Heart,Cardiac Muscle,Myocardia,Cardiac Muscles,Heart Muscle,Heart Muscles,Muscles, Cardiac,Muscles, Heart
D011898	Ranidae	The family of true frogs of the order Anura. The family occurs worldwide except in Antarctica.	Frogs, True,Rana,Frog, True,True Frog,True Frogs
D004625	Embryo, Nonmammalian	The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.	Embryonic Structures, Nonmammalian,Embryo, Non-Mammalian,Embryonic Structures, Non-Mammalian,Nonmammalian Embryo,Nonmammalian Embryo Structures,Nonmammalian Embryonic Structures,Embryo Structure, Nonmammalian,Embryo Structures, Nonmammalian,Embryo, Non Mammalian,Embryonic Structure, Non-Mammalian,Embryonic Structure, Nonmammalian,Embryonic Structures, Non Mammalian,Embryos, Non-Mammalian,Embryos, Nonmammalian,Non-Mammalian Embryo,Non-Mammalian Embryonic Structure,Non-Mammalian Embryonic Structures,Non-Mammalian Embryos,Nonmammalian Embryo Structure,Nonmammalian Embryonic Structure,Nonmammalian Embryos,Structure, Non-Mammalian Embryonic,Structure, Nonmammalian Embryo,Structure, Nonmammalian Embryonic,Structures, Non-Mammalian Embryonic,Structures, Nonmammalian Embryo,Structures, Nonmammalian Embryonic
D005121	Extremities	The farthest or outermost projections of the body, such as the HAND and FOOT.	Limbs,Extremity,Limb
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA
D013623	Tail	An extension of the posterior of an animal body beyond the TORSO.	Tails