Analysis of Schizosaccharomyces pombe meiosis by nuclear spreading.

The fission yeast, Schizosaccharomyces pombe, much like the budding yeast, is a particularly well-suited model organism for genetic research. However, the miniscule size of both yeasts' nuclei has hindered their success as research models for cytologists. A solution to this problem is provided by the spreading of nuclei, which increases their volume and allows for a better spatial resolution of nuclear contents. Here we describe nuclear spreading in fission yeast. Spreading of meiotic nuclei is particularly helpful in exposing the linear elements (LinEs), which are the fission yeasts' rudimentary version of the synaptonemal complex. Although the LinEs' role is still not fully understood, they serve as important meiotic hallmarks and their presence and morphology can be used in characterizing meiotic mutants. We first describe methods to induce meiosis in liquid cell cultures, then outline a method to break down cell and nuclear membranes by detergent treatment to release chromatin on cytological slides, and finally provide a set of protocols for analyzing these nuclei by immunostaining and fluorescence in situ hybridization (FISH), and by electron microscopy.