An antibody against purified chicken skeletal muscle tropomyosin is used in indirect immunofluorescence to visualize the localization of tropomyosin in a variety of nonmuscle cells. The antibody produces a fluorescent pattern which is very similar to that obtained with an actin-specific antibody. This pattern is composed of fluorescent fibers which are shown to be coincident with the fibers see...

The fraction of polyclonal caldesmon antibodies cross-reacting with rabbit skeletal troponin T are shown to compete with smooth muscle tropomyosin for caldesmon and troponin T, as revealed by ELISA method. The epitope recognized by these antibodies was also found in Mr 77 kDa non-muscle caldesmon. These results provide functional confirmation for the suggestion that the regions of amino acid se...

Myosin, tropomyosin, and actin were localized in the epithelial cells of rat intestine by means of specific antibodies to chicken gizzard smooth muscle myosin, tropomyosin, and actin by immunohistochemical studies at both the light and electron microscope levels (unlabeled antibody enzyme technique). The pattern of antibody staining was the following (a) Anti-actin was associated with the micro...

Chick heart development was studied using transmission electron microscopy and SDS-polyacrylamide gel electrophoresis in combination with densitometry. Myosin heavy chain, alpha-actinin, actin and tropomyosin accumulations were analysed in developing hearts from preheartbeat stage 9 (Hamburger-Hamilton staging series) through 2 days after hatching. At the preheartbeat stage, electron microscopy...

Analyses of the binding of tropomyosin to muscle and Acanthamoeba actin by the use of Scatchard plots indicate that the binding exhibits strong positive cooperativity in the presence of Mg2+. The cooperative nature of the binding is not affected by the presence of 80 mm KCl, but appears to decrease somewhat in the presence of heavy meromyosin or subfragment-1. Heavy meromyosin, subfragment-1, a...

The smooth/skeletal muscle beta-tropomyosin gene contains an additional exon (exon 1') which is located between exons 2 and 3 and which is used to generate a 1.3-kb transcript expressed in undifferentiated muscle as well as nonmuscle cells. This mRNA, besides exon 1', corresponds to exons 3, 4, 5, 6A, 7, 8, and 9B of the gene and codes for a 247-amino acid low molecular weight tropomyosin. Exon...

Spatially distinct populations of microfilaments, characterized by different tropomyosin (Tm) isoforms, are present within a neuron. To investigate the impact of altered tropomyosin isoform expression on neuronal morphogenesis, embryonic cortical neurons from transgenic mice expressing the isoforms Tm3 and Tm5NM1, under the control of the beta-actin promoter, were cultured in vitro. Exogenously...

The actin cytoskeleton is required for many aspects of cell division in yeast, including mitochondrial partitioning into growing buds (mitochondrial inheritance). Yeast cells lacking MDM20 function display defects in both mitochondrial inheritance and actin organization, specifically, a lack of visible actin cables and enhanced sensitivity to Latrunculin A. mdm20 mutants also exhibit a temperat...

The extents of superprecipitation and contractile protein contents of myosin B in the myocardium and conduction system were compared. The extents of superprecipitation of myosin B of the two types of cardiac muscle were similar, but the onset of the superprecipitation reaction of myosin B from the conduction system was delayed and the clearing phase of the reaction was prolonged. On sodium dode...