Variations on a theme: Imaging cytokinetic and stable rings in situ using Caenorhabditis elegans.

Cytokinesis is an essential event in canonical cell division. In multicellular organisms, cells must divide in the context of neighboring cells in intact tissues. Recent studies have shown that tissue architecture can regulate the dynamics of and molecular requirements for cytokinesis. On the other hand, regulated cytokinesis failure occurs in, and is required for the proper function of, certain cell types and tissues including cardiomyocytes, hepatocytes, and germ lines. One way to build our understanding of cytokinesis in diverse cell types is to visualize cytokinesis in intact tissues. The nematode Caenorhabditis elegans is a powerful system for such inquiries due to the well-characterized, invariant lineage of each of its cells, the ease of genomic modifications including tagging proteins, and many more advantages. The clear cuticle of C. elegans allows for live imaging of intact tissues; however, the worm's motility can confound imaging. Here we introduce two C. elegans tissues, an epithelial tissue and the germ line, both excellent systems for the study of cytokinesis in the context of an intact animal. Additionally, we present three protocols for overcoming the challenges of live imaging in C. elegans.