caa a22 4500 475745167 CHVBK 20180406123511.0 cr unu---uuuuu 170329e20001101xx s 000 0 eng 10.1023/A:1010374424143 doi (NATIONALLICENCE)springer-10.1023/A:1010374424143 Dynamics of Actin and α-Actinin in Nascent Myofibrils and Stress Fibers [Elektronische Daten] [Fukuko Hasebe-Kishi, Yutaka Shimada] Actin labeled with fluorescein isothiocyanate (FITC) and α-actinin labeled with rhodamine (rh) were co-injected into chick embryonic cardiac myocytes and fibroblasts. In cardiomyocytes, FITC-actin was distributed in nonstriated lines, linearly arranged punctate structures with short intervals, and cross-striated bands with regular sarcomeric intervals. rh-α-Actinin was seen to be distributed in the same pattern in the former two portions, and in the center of each striation in the latter portion. Photobleaching of structures incorporated with these fluorescent analogs revealed that the fluorescent recovery rate of actin decreased in the order of nonstriated > punctated > striated portions, while that of α-actinin was low and stable at all portions. During the transition phase from punctate to regular sarcomere structures of these proteins, short spaced α-actinin dots adjoined each other and aligned with Z bands of neighboring myofibrils. It appears that both the difference in exchangeability between actin and α-actinin molecules and the movement of α-actinin dots during this phase of myofibrillogenesis are related to sarcomere lengthening and I-Z-I brush formation; adjoining dots of low-exchangeable α-actinin may provide favorable situations for exchangeable actin molecules in filaments to elongate and/or rearrange. In fibroblasts, both FITC-actin and rh-α-actinin formed nonstriated lines. In these cells, exchangeabilities of both proteins were high and similar in rate. This seems to indicate that stress fibers are constantly exchanging their components for motile and other vital functions of these cells. The high exchangeabilities of both proteins in stress fibers show that these fibers are clearly different from nonstriated, stress-fiber like structures of nascent myofibrils. Kluwer Academic Publishers, 2000 Hasebe-Kishi Fukuko Department of Anatomy and Cell Biology, Chiba University School of Medicine, Chiba, Japan aut Shimada Yutaka Department of Anatomy and Cell Biology, Chiba University School of Medicine, Chiba, Japan aut Journal of Muscle Research & Cell Motility Kluwer Academic Publishers 21/8(2000-11-01), 717-724 0142-4319 21:8<717 2000 21 10974 https://doi.org/10.1023/A:1010374424143 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1010374424143 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hasebe-Kishi Fukuko Department of Anatomy and Cell Biology, Chiba University School of Medicine, Chiba, Japan aut NATIONALLICENCE 700 1- Shimada Yutaka Department of Anatomy and Cell Biology, Chiba University School of Medicine, Chiba, Japan aut NATIONALLICENCE 773 0- Journal of Muscle Research & Cell Motility Kluwer Academic Publishers 21/8(2000-11-01), 717-724 0142-4319 21:8<717 2000 21 10974 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer