Laser killing of blastomeres in Caenorhabditis elegans.

The Caenorhabditis elegans embryo is particularly amenable to microscopy and embryological studies because of its short developmental time, transparent shell, and nonpigmented cells. Within the embryo, contacts between cells often establish the polarization of neighboring cells. Blastomere isolation and recombination experiments have led to a wealth of understanding of the events in the four-cell C. elegans embryo. However, identifying individual blastomeres after isolation at stages past the four-cell stage is limited. In addition, removal of blastomeres from their native surroundings can interfere with many cell contacts besides the contacts of interest. An alternative approach for studying cell interactions within the C. elegans embryo is to use laser ablation of individual cells. Laser ablation can be used to kill one of two cells in contact with each other to understand what happens when a cell no longer signals to its neighbor. Additionally, killing a cell that is between two cells that will eventually contact each other can result in the corpse of the cell forming a steric barrier between the cells, preventing the contact. This protocol describes laser ablation of embryos mounted on an agar mount.