Factors inducing the activation of reconstructed oocytes of farm animals in somatic cloning procedures

Abstract

Artificial activation of reconstructed oocytes is induced with various physical or chemical factors, which can be used in a number of activation protocols such as pre-activation, simultaneous activation and fusion and post-activation. The post-activation protocol is the most common and brings best effects in somatic cloning of farm animals. The artificial activation model is still different from the natural model of oocyte activation by penetrating spermatozoon, as is the case with fertilization. For this reason the protocols for artificial activation of reconstructed oocytes continue to be modified. Current studies on the improvement of oocyte artificial activation methods centre around the optimization of the electric field parameters and on the association of the activating factors with blockers of the activity of cyclin-dependent kinases or protein synthesis. The optimum activation method will make possible the complete reprogramming of exogenous cell nuclei and thus improve the ultimate efficiency of somatic cloning in farm animals.