N-terminally endogenous mKate2-tagged HIM-4 in Caenorhabditis elegans

The gene him-4 encodes the C. elegans homolog of hemicentin, an evolutionarily conserved extracellular matrix protein. Despite being an extracellular matrix protein, mutations in him-4 result in pleiotropic defects during development and demonstrate tissue fragility. While previous studies in C. elegans have confirmed the localization of either transgenic HIM-4::GFP or endogenous C-terminally tagged HIM-4::mNeonGreen, only green or green/yellow fluorescent protein-tagged HIM-4 are available to the C. elegans community. Here, I used CRISPR/Cas9 technology to insert the far-red fluorescence protein mKate2 at the him-4 genomic locus, and established worms expressing mKate2::HIM-4. As expected, localization of mkate2::HIM-4 at the rachis was observed at the L4 stage. In contrast to the localization of type IV collagen or nidogen such as major components of the basement membrane, mkate2::HIM-4 was polarized at the anterior part of the pharyngeal basement membrane. A unique polarized localization pattern of pharyngeal basement membrane is maintained throughout the L1-L4 stages.