Hemicentins Assemble on Diverse Epithelia in the Mouse

Hemicentins are recently described extracellular matrix (ECM) proteins with a single ortholog in C. elegans that assembles into discrete tracks constricting broad regions of epithelial cell contact into adhesive and flexible line-shaped junctions. There are two highly conserved hemicentin genes in most vertebrate species; however, nothing is known about the function or distribution of vertebrate hemicentins. To determine the distribution of vertebrate hemicentins, we used a polyclonal antibody to stain mouse tissue and showed that hemicentins are found in the pericellular ECM of epithelial cells in a number of tissues including embryonic trophectoderm and adult skin and tongue, in addition to the ECM of some, but not all, blood vessels. Hemicentins also assemble on multiple epithelia in the eye, including cornea, lens, and retina. The pericellular localization of vertebrate hemicentins on epithelia and other cell surfaces suggests that vertebrate hemicentins, like their nematode counterpart, are secreted ECM proteins likely to have a role in the architecture of adhesive and flexible cell junctions, particularly in tissues subject to significant amounts of mechanical stress.