Expression of the integrin subunits α5, α6 and β1 in the testes of the common marmoset

Abstract

Integrin subunits α5, α6 and β1 were localized in the testis of pre-pubertal or adult non-human primates (Callithrix jacchus) by immunofluorescence staining and in situ hybridization. In animals of all ages subunits α5 and β1 were localized in cells of the lamina propria of the seminiferous epithelium. In prepubertal animals, the integrin subunits α5, α6, as well as β1, were distributed all over the plasma membrane of Sertoli cells. In adult animals the integrin subunits were confined to those plasma membrane regions of Sertoli cells which are assigned to the basal compartment, including the basement membrane of the seminiferous tubules. Protein expression of intrgrin subunits α6 and β1 was most pronounced in tubular stages in which elongated spermatids were not yet present in the adluminal compartment of the epithelium, suggesting that these integrin subunits are particularly essential at certain developmental stages of spermatogenesis. Non-radioactive in situ hybridization revealed that the mRNA for integrin subunits α5, α6 and β1 was expressed by Sertoli cells. In situ hybridization, together with immunofluorescence data, shows that these integrin subunits were exclusively synthesized in Sertoli cells. As to functional aspects, it is concluded that during primate spermatogenesis, Sertoli cell integrins may be involved in both cell matrix as well as cell-cell interactions, particularly during early spermatogenesis.