Chapter 4 Permeabilized Cell Models for Studying Chromosome Movement in Dividing PtK1 Cell

Abstract

This chapter discusses the permeabilized cell models for studying chromosome movement in dividing PtK cells. PtK cells are utilized for making permeabilized cell models because their size and morphology is well suited for studying mitosis. These cells are large for tissue culture cells, and have metaphase spindles that are over 10 μm long. It is found that although the cells change shape and thicken as they enter mitosis, dividing cells do not round up to the same extent as most other cells. It is observed that although the PtK, cell line is considered to be stable, a significant proportion of these cells appear to be polyploid or have abnormal mitotic spindles. The easiest way to recognize abnormal spindle morphology is to examine dividing cells with polarization optics. The phase and Nomarski appearance of the cells after lysis are not greatly altered. Immediately after lysis, the rod-shaped mitochondria round up and appear to fragment. The density of staining of the ground substance is similar in lysed and unlysed cells, and microfilaments, intermediate filaments, and microtubules are present in both classes of cells. The other membranous organelles in the permeabilized cell do not appear to be noticeably disrupted, although the mitochondria are swollen and the cristae distorted.