Vezatin, a ubiquitous protein of adherens cell-cell junctions, is exclusively expressed in germ cells in mouse testis.
In the male reproductive organs of mammals, the formation of spermatozoa takes place during two successive phases: differentiation (in the testis) and maturation (in the epididymis). The first phase, spermiogenesis, relies on a unique adherens junction, the apical ectoplasmic specialization linking the epithelial Sertoli cells to immature differentiating spermatids. Vezatin is a transmembrane protein associated with adherens junctions and the actin cytoskeleton in most epithelial cells. We report here the expression profile of vezatin during spermatogenesis. Vezatin is exclusively expressed in haploid germ cells. Immunocytochemical and ultrastructural analyses showed that vezatin intimately coincides, temporally and spatially, with acrosome formation. While vezatin is a transmembrane protein associated with adherens junctions in many epithelial cells, it is not seen at the ectoplasmic specializations, neither at the basal nor at the apical sites, in the seminiferous epithelium. In particular, vezatin does not colocalize with espin and myosin VIIa, two molecular markers of the ectoplasmic specialization. In differentiating spermatids, ultrastructural data indicate that vezatin localizes in the acrosome. In epididymal sperm, vezatin localizes also to the outer acrosomal membrane. Considering its developmental and molecular characteristics, vezatin may be involved in the assembly/stability of this spermatic membrane.
Hyenne
Vincent
V
Biologie Cellulaire du Développement, UMR 7622, CNRS, Université Pierre et Marie Curie, 9 Quai St Bernard, 75252 Paris cedex 05, France.
Harf
Juergen C
JC
Latz
Martin
M
Maro
Bernard
B
Wolfrum
Uwe
U
Simmler
Marie-Christine
MC
D000177:Acrosome / Q000737:chemistry; D022005:Adherens Junctions / Q000737:chemistry*; D000818:Animals; D015153:Blotting, Western / Q000379:methods; D002352:Carrier Proteins / Q000032:analysis*; D002462:Cell Membrane / Q000737:chemistry; D008297:Male; D008565:Membrane Proteins / Q000032:analysis*; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D016253:Microscopy, Immunoelectron; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013094:Spermatozoa / Q000737:chemistry*
D002352:Carrier Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger; C506603:vezatin protein, mouse