Quantification of Synapsis Using Immunolocalization in Embedded Nuclei of Lolium

Abstract

The establishment, formation and disassembly of the synaptonemal complex (SC) is intimately associated with other essential processes that occur during prophase I of meiosis, including recombination. Labeling the SC using primary antibodies raised against key proteins, detected using secondary antibodies conjugated to fluorescent dyes, differentiate between synapsed and unsynapsed regions, revealing the dynamics of the process. Embedding meiotic nuclei in acrylamide pads preserves the three-dimensional (3D) organization of the chromosomes, which can be optically sectioned using confocal laser scanning microscopy to produce a faithful representation of the SC at the point of fixation. Deconvolution, and processing using Imaris allows the axes to be isolated from the nucleus and their features measured. Here, I describe a robust protocol to quantify the SC using immunofluorescence in Lolium perenne and L. temulentum.