Identification of beta and gamma subunits of laminins localized in the basement membrane of rat circumvallate papillae.

Taste bud cells have elongated shape and are anchored to the basement membrane. Here we analyzed the subunits of laminin, a major component of the basement membrane, in circumvallate papillae of rat tongue. Two beta subunits, beta1 and beta2, were detected by RT-PCR, of which the beta2 subunit was immunohistochemically identified as a major component of the basement membrane. The gamma1 subunit was also immunohistochemically identified as a major component. Profiles of these two laminin subunits were nearly the same as that obtained by an anti-laminin antibody, indicating that laminins of the basement membrane in the papillae contain beta2 and gamma1 as major beta and gamma subunits, respectively. As potential receptors for these laminin ligands, integrin subunits were analyzed by RTPCR. Three integrin beta subunit species, beta1, beta4, and beta5, were shown to be expressed in the epithelium of the circumvallate papillae by RT-PCR among the five species examined.