KENBIKYO Vol.48▶No.2 2013
■Feature Articles: Imaging Cytoskeletons

Structural Analysis for Actin Filaments in the Cell by Electron Tomography

Akihiro Narita

Abstract: Although electron tomography has been rapidly developed, it is still difficult to analyze fine structures such as protein complexes in the cell. It is mainly because of two reasons: 1. Poor signal to noise ratio in the cell because of cytosol. 2. Missing wedge or missing pyramid caused by limited tilt angles of the sample deform the reconstructed three-dimensional map. We have developed structural analysis methods for filamentous complexes, especially for actin filaments in the cell. John Victor Small’s group, our co-researchers, has enhanced the signal to noise ratio by staining the cell negatively. We have developed an image analysis system for analyzing electron tomograms of the negatively stained cells, which enabled us to determine polarity of the actin filaments without any labeling. We review these methods in this article.

Key words: Electron tomography, actin filament, image analysis, negatively staining