Murine Embryonic Stem Cells as a Model for Stress Proteins and Apoptosis During Differentiation

The early phase of murine embryonic stem (ES) cell differentiation is accompanied with the expression of proteins that are key players in this phenomenon. The function of some these proteins can be analyzed by using the classical “knock-out gene technology”, that consists of the inactivation of the endogenous gene that encodes the studied protein. This approach can be considered if the analyzed protein does not play a vital role; in other words, if the cells can stillundergo differentiation without expressing the protein in question. To analyze proteins whose expression is essential during early differentiation, an antisense strategy can be used that interferes with the expression of the studied protein. One interesting protein we studied with this technique is the small stress protein Hsp27 (1 ).