PKC in eggs and embryos

After a spermatozoon enters the egg, rapid processes such as the cortical g ranules exocytosis (CGE) occur. Other, later processes are observed as well , and they include resumption of the second meiotic division, second polar body (PBII) extrusion and rearrangement of the DNA inside the pronuclei (PN ). The above mentioned biochemical processes involve signal transduction pa thways that are well known in other cell systems, and require mediation of second messengers like Ca2+ and diacylglycerol (DAG) which are protein kina se C (PKC) activators. The present review, based upon recently published st udies, raises the possibility of PKC involvement in fertilization and in ea rly developmental stages of the mammalian embryo.