Expression of myosin heavy chain transcripts in normal and cardiac mutant Mexican axolotls.
In this study, we have cloned a 1.0 kb myosin heavy chain (MHC) cDNA by screening an axolotl heart cDNA library with the monoclonal antibody MF20 against a light meromyosin (LMM) region of MHC. The nucleotide sequence analysis shows 85-86% homology at the amino acid and 78-81% homology at the nucleic acid level with MHC from other vertebrates. Phylogenetic analyses suggest that axolotl beta-MHC forms a cluster with the myosin II group of vertebrate striated muscles. Within the myosin II cluster, axolotl beta-MHC forms a distinct subclade from avian MHC and is instead closer to mammalian MHC. RT-PCR analyses show that transcripts of beta-MHC are present at stage 2 and the onset of the MHC gene expression is at stage 8-10 (gastrulation). Expression increases with embryonic development and reaches a maximum at stage 20. Beyond stage 35, the heart-beat initiation stage, the expression level of beta-MHC is higher in cardiac muscle than in skeletal muscle. We could not detect significant differences in the levels of expression of MHC transcripts in normal and cardiac lethal mutant (c/c) axolotls (Ambystoma mexicanum).
Ward
S M
SM
Department of Anatomy and Cell Biology, SUNY Health Science Center at Syracuse, New York 13210, USA.
Spinner
B J
BJ
Dube
A
A
Gaur
A
A
Erginel-Unaltuna
N
N
Lemanski
L F
LF
Dube
D K
DK
D000558:Ambystoma mexicanum; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000737:chemistry; D019143:Evolution, Molecular; D018507:Gene Expression Regulation, Developmental; D006321:Heart / Q000196:embryology / Q000254:growth & development; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009206:Myocardium / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000737:chemistry / Q000235:genetics*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017421:Sequence Analysis
D000911:Antibodies, Monoclonal; D017931:DNA Primers; D018995:Myosin Heavy Chains