Role of phospholipase C in nuclear envelope assembly

The nuclear envelope is a dynamic double-bilayer membrane that segregates the nucleus from the cytoplasm. During mitosis it breaks down in prophase and is reformed around the daughter chromosomes in late anaphase/telophase. A similar nuclear envelope disassembly/assembly process takes place at fertilization around the sperm nucleus shortly after the sperm has penetrated the egg. Cell-free systems modeling the latter event have been devised in several non-mammalian species and are routinely used as models for somatic nuclear envelope formation. They pose several advantages over working with more complex systems and to date a number of seminal discoveries in nuclear envelope formation have been made using such systems. We have used a cell-free system derived from sea urchin gametes to study the role of membrane fusion events in nuclear envelope formation, with particular attention to the role of phosphoinositide lipids and PLC gamma. This review will describe our findings and discuss how they integrate into the current model of nuclear envelope formation.