Molecular and Cellular Mechanisms Underlying Preimplantation Embryo Development

Abstract

Preimplantation embryo development refers to the maturation of a fertilized ovum to a blastocyst. This process is highly regulated and required for proper implantation of the blastocyst into the endometrium. During this phase, several tasks must be accomplished. The differentiated zygotic genome must undergo reprogramming back to totipotency in order to generate all of the different types of tissue making up a human. Next, certain cells begin to differentiate to prepare for implantation which occurs at approximately day 7 post-fertilization. This progression is a result of a careful interplay between maternally persistent RNA transcripts and activation of the zygotic genome. After the embryonic genome activation, blastomere differentiation begins to occur. Cellular polarity has been shown to be the signal transduction that initiates this differentiation. Understanding the molecular and cellular mechanisms regulating preimplantation embryo development is of fundamental importance for reproductive science and has numerous applications in fields such as assisted reproductive technology and stem cell therapy.