Muscle cells infected at the permissive temperature with temperature-sensitive mutants of Rous sarcoma virus and shifted to the non-permissive temperature form myotubes that are unable to cluster acetylcholine receptors (Anthony, D. T., S. M. Schuetze, and L. L. Rubin. 1984. Proc. Natl. Acad. Sci. USA. 81:2265-2269). Work described in this paper demonstrates that the virally-infected cells are ...

Recessive mutant gene c in axolotl embryos results in an absence of normal heart function. Immunofluorescence studies were done to determine the distributions of myosin, tropomyosin and alpha-actinin in the hearts of normal and mutant siblings. Anti-myosin specifically stains the A bands of myofibrils in normal hearts and reveals a progressive increase in myofibril organization with development...

Tilapia is a very common aquaculture species in Taiwan and both the so-called freshwater tilapia (Oreochromis niloticus) and seawater tilapia (O. mossambica) are available. In order to characterize muscle tropomyosin from these tilapia and hybrid ones (O. mossambica × O. niloticus ), the biochemical properties of tropomyosin among these tilapia species were analysed. The nucleotide sequences of...

The length and amino acid sequence of the amino-terminal region of troponin T (TnT) is regulated by alternative mRNA processing in both mammals and birds. To study the function of this region, three forms of bovine cardiac TnT were compared: isoforms TnT1 and TnT2, which differ by the presence or absence of residues 15-19 and TnT 39-284. TnT 39-284 was prepared by chemical cleavage of TnT1 at C...

A theory developed previously for the stability of the native structure in two-chain, a-helical coiled coils is applied to singly (disulfide) cross-linked tropomyosin and to a singly (disulfide) cross-linked, synthetic, 43-residue peptide analogue (called here XY5) of tropomyosin. Algorithms are obtained from fits of extant data for the helix stability parameter (s) for each amino acid residue ...

During the spreading of a population of rat embryo cells, approximately 40% of the cells develop a strikingly regular network which precedes the formation of the straight actin filament bundles seen in the fully spread out cells. Immunofluorescence studies with antibodies specific for the skeletal muscle structural proteins actin, alpha-actinin, and tropomyosin indicate that this network is com...

Thin-filament regulation of smooth muscle contraction involves phosphorylation, association, and dissociation of contractile proteins in response to agonist stimulation. Phosphorylation of caldesmon weakens its association with actin leading to actomyosin interaction and contraction. Present data from colonic smooth muscle cells indicate that acetylcholine induced a significant association of c...

Tropomyosins consist of nearly 100% alpha-helix and assemble into parallel and in-register coiled-coil dimers. In vitro it has been established that nonmuscle as well as native muscle tropomyosins can form homodimers. However, a mixture of muscle alpha and beta tropomyosin subunits results in the formation of the thermodynamically more stable alpha/beta heterodimer. Although the assembly prefer...