Abstract
Abstract: :
Purpose: Gelatinous drop–like corneal dystrophy (GDLD, MIM 204870) is an autosomal recessive disorder characterized by severe corneal amyloidosis. Tsujikawa et al. (1999) identified the gene responsible for GDLD, membrane component, chromosome 1, surface marker 1(M1S1) by positional cloning method and detected the disease–causing mutations. Although M1S1 exhibits homology with Ep–CAM (epithelial cell adhesion molecule)gene related to epithelial cell adhesion, the function of M1S1 protein is still not clear. In the present study, we attempted to determine the cell–cell adhesion function of disease–causing M1S1 missense mutant protein. Methods: A DNA segment containing an entire open reading frame of M1S1 gene with normal sequence or a single base substitution, C108R, was ligated into an expression vector pcDNA3.1/mic–His B(Invirogen Life Technologies). Each construct was transfected into CHO cells and cultured. Cell adhesion activity was counted as cell cluster ratio using gyratory incubation. Results: Cell adhesion activity of M1S1 missense mutant protein was almost half as much as wild type M1S1 protein. Conclusions: M1S1 protein exhibits aell adhesion activity. Abnormal M1S1 may disturb epithelial barrier function in GDLD patients.
Keywords: cell adhesions/cell junctions • cornea: epithelium • gene/expression