Tracking and ablating subpopulations of epiblast cells in the chick embryo.

The early chick embryo contains subpopulations of cells that express lineage-specific transcription factors. We have developed protocols to examine the role of these cells during development that involve labeling them for cell tracking purposes and ablating them within the epiblast. The procedures take advantage of the fact that subpopulations of epiblast cells differentially express cell surface antigens recognized by monoclonal antibodies. Embryos are removed from the shell and incubated on the yolk with an antibody. Cells that bind the antibody are either tagged with a fluorescent secondary antibody or lysed with complement. For long-term analyses, embryos are returned to a host shell and placed in an incubator. This method of whole embryo manipulation ex-ovo and incubation in-ovo supports normal development into the fetal period.