The centrosome and early embryogenesis: clinical insights

In humans and most mammals, with the exception of some rodents notably the mouse, the centrosome, which is the organizing centre of the spindle, is uniparentally (paternally) inherited. The sperm centrosome is transmitted to the egg at fertilization, forming an aster comprising radially arrayed microtubules that brings the male and female pronuclei into close apposition and organizes the first mitotic spindle in the zygote. Each centrosome contains a pair of centrioles that are oriented perpendicular to one another, surrounded by dense fibrillar pericentriolar material, within which functional and regulatory molecules are embedded. The centrosome is a complex organelle with a crucial role to play in human fertility and the ability of human embryos to undergo normal development. Centrosomal defects can lead to failure in fertilization, and cause embryonic arrest through the formation of abnormal spindles and the accumulation of chromosomally abnormal cells that derive from them. This paper is a brief review of the role of the centrosome and the implications of its dysfunction in early embryogenesis, with particular reference to the human embryo.