Germ Cell Migration Across Sertoli Cell Tight Junctions

Abstract

Observing Sperm Factories The blood-testis barrier creates a permissive microenvironment for germ cell differentiation and protects meiotic germ cells from autoimmunity. To become sperm, large cysts of germline progenitors must cross the blood-testis barrier without causing damage. Smith and Braun (p. 798 , published online 20 September) show that somatic Sertoli cells, the gate-keepers of the blood-testis barrier, manage this task by building a network of compartments bounded by old and new tight junctions. Intercellular bridges, which connect germ cells within cysts, span the transient compartments by passing through vertical strands at tricellular junctions. Only after the formation of a new blood-testis barrier are old tight junctions removed and germ cells released.