Heterogeneity and tissue specificity of tropomyosin isoforms included
in various muscles of the spiny lobster, Panulirus japonicus, were inv
estigated using two-dimensional ureashift gel electrophoresis, two-dim
ensional gel electrophoresis with first dimension isoelectric focusing
and second dimension sodium dodecyl sulfate gels, and immunoblotting.
Four kinds of tropomyosin isoforms were recognized as major component
s in spiny lobster muscles, and distribution of these isoforms was con
siderably tissue-specific. Three kinds of tropomyosin isoforms designa
ted as TMa, TMb, and TMc in the present study were detected in abdomin
al and cephalothoracic muscles. TMa was detected predominantly in fast
muscles, TMb predominantly in slow muscles and it was the only isofor
m in leg muscles, and TMc was found preferentially in the dorsal-side
fast muscles. Six distribution patterns of tropomyosin isoforms, two f
ast-type, two slow-type, thoracic-type and leg-type, were detected in
the skeletal muscle tissues. A unique tropomyosin constituent designat
ed as TMh was observed as the main component in the heart muscle. The
antisera against TMa and TMb showed that these isoforms had the epitop
es specific to the respective isoforms as well as those common to both
isoforms. The antisera specific to TMa and TMb were prepared by absor
ption of the antibodies common to both isoforms from the respective an
tisera. From immunoblot analysis of TMc and TMh with the absorbed anti
sera, it was shown that these isoforms had rather TMa-type antigenicit
ies. (C) 1997 Wiley-Liss, Inc.