Localization of actin filaments on mitotic apparatus in tobacco BY-2 cells

• Published in: Planta Vol. 222; no. 1; pp. 118 - 129
• Main Authors: Yasuda, H, Kanda, K, Suenaga, K, Kidou, S, Ejiri, S
• Format: Journal Article
• Language: English
• Published: Berlin Springer-Verlag 01.09.2005; Springer; Springer Nature B.V
• Subjects: actin; Actin Cytoskeleton - chemistry; Actin Cytoskeleton - drug effects; Actin Cytoskeleton - metabolism; Actins; Actins - chemistry; Actins - genetics; Actins - immunology; Actins - metabolism; Amino Acid Sequence; amino acid sequences; Animals; Antibodies; Benzamides - pharmacology; Biological and medical sciences; Cell kinetics; Cell physiology; cell suspension culture; Cells, Cultured; chromosome segregation; Chromosomes; cultured cells; cytochalasin D; Cytochalasin D - pharmacology; Cytochalasins; Cytoskeleton; Fundamental and applied biological sciences. Psychology; HeLa cells; Humans; Microfilaments; Microtubules; Mitosis; Mitotic spindle apparatus; Molecular Sequence Data; Nicotiana - cytology; Nicotiana tabacum; nucleotide sequences; Phylogeny; plant biochemistry; Plant cells; plant physiology; Plant physiology and development; propyzamide; Proteins; Sequence Homology, Amino Acid; Spindle Apparatus - drug effects; Spindle Apparatus - metabolism; tobacco; Actin filament; Nicotiana; Mitosis; Spindle body; Cytochalasin D; Nicotiana tahacum; BY-2 cell; Cytochalasin; Complementary DNA; Dicotyledones; Angiospermae; Cytoskeleton; Spermatophyta; Solanaceae; Microtubule
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-005-1522-8

Actin filaments are among the major components of the cytoskeleton, and participate in various cellular dynamic processes. However, conflicting results had been obtained on the localization of actin filaments on the mitotic apparatus and their participation in the process of chromosome segregation. We demonstrated by using rhodamine-phalloidin staining, the localization of actin filaments on the mitotic spindles of tobacco BY-2 cells when the cells were treated with cytochalasin D. At prophase, several clear spots were observed at or near the kinetochores of the chromosomes. At anaphase, the actin filaments that appeared to be pulling chromosomes toward the division poles were demonstrated. However, as there was a slight possibility that these results might have been the artifacts of cytochalasin D treatment or the phalloidin staining, we analyzed the localization of actin filaments at the mitotic apparatus immunologically. We cloned a novel BY-2 alpha-type actin cDNA and prepared a BY-2 actin antibody. The fluorescence of the anti-BY-2 actin antibody was clearly observed at the mitotic apparatus in both non-treated and cytochalasin D-treated BY-2 cells during mitosis. The facts that similar results were obtained in both actin staining with rhodamine-phalloidin and immunostaining with actin antibody strongly indicate the participation of actin in the organization of the spindle body or in the process of chromosome segregation. Furthermore, both filamentous actin and spindle bodies disappeared in the cells treated with propyzamide, which depolymerizes microtubules, supporting the notion that actin filaments are associated with microtubules organizing the spindle body.