Sperm chemotaxis in marine invertebrates and mammals

Sperm respond to multiple chemical factors derived from the eggs and reorient their migratory direction – a process called chemotaxis. The chemotaxis of sperm in marine invertebrates has been established well. A couple of ion channels and enzymes are involved in the signal transduction pathway of sperm chemotaxis. In contrast, the mechanism of sperm chemotaxis in mammals is still rudimentary. Although much less is known about the chemotaxis of mammalian sperm, the feature of chemotaxis has been utilized to recruit sperm at the optimum functional state, which may improve the efficiency of assisted reproductive technology. In this review, we summarize potent chemoattractants and molecular regulatory mechanism in marine invertebrates and mammals and discuss the application of chemotaxis in clinical treatment.