J Phycol. 2011 Oct;47(5):1121-30. doi: 10.1111/j.1529-8817.2011.01039.x. Epub 2011 Aug 29.

CORTICAL F-ACTIN REORGANIZATION AND A CONTRACTILE RING-LIKE STRUCTURE FOUND DURING THE CELL CYCLE IN THE RED CRYPTOMONAD, PYRENOMONAS HELGOLANDII(1).

Journal of phycology

Takahiro Yamagishi, Hiroshi Kawai

PMID: 27020194 DOI: 10.1111/j.1529-8817.2011.01039.x

Abstract

Cortical F-actin reorganization during the cell cycle was observed in Pyrenomonas helgolandii U. J. Santore (SAG 28.87) for the first time in Cryptophyta using fluorescein-isothiocyanate (FITC)-phalloidin staining. In interphase, a number of F-actin bundles were observed as straight lines running parallel to the long axis of the cell on the cell cortical region. They extended from an F-actin bundle that runs along the margin of the vestibulum. Although the F-actin bundles running parallel to the long axis of the cell disappeared during anaphase, they gradually reappeared in telophase. By contrast, the F-actin bundle along the vestibulum margin remained visible during cytokinesis and dynamically changed following the enlargement of the vestibulum, suggesting that F-actin was involved in the mechanism of vestibulum enlargement. F-actins were not found in the cytoplasmic and nucleoplasmic regions throughout the cell cycle. In addition, a contractile ring-like structure appeared at the cleavage furrow during cytokinesis. Treatment with cytochalasin B and latrunculin B significantly inhibited the formation of cleavage furrow, resulting in forming an abnormal cell with two nuclei, suggesting that cytokinesis in P. helgolandii is controlled by the contractile ring-like structure constituted of F-actin.

© 2011 Phycological Society of America.

Keywords: F-actin; Pyrenomonas; cleavage furrow; contractile ring; cryptophyte; cytochalasin; cytokinesis; phalloidin

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