Cross-Linked Features of Mouse Pelage Hair Resistant to Detergent Extraction

The study investigated cross-linking defects in the hair cuticle of 13 mouse mutants with defective hair, using sodium dodecyl sulfate and dithiothreitol extraction followed by transmission electron microscopy. While the medulla and cortex of the hair fibers appeared normal post-extraction, the cortex keratins were fully extractable, and the medulla cells remained largely unextracted. Notably, two mutants (matted/flaky tail and naked) showed more extensive cuticle extraction, indicating defective cross-linking. This defect was specific to the cuticle and did not affect the cortex or medulla, suggesting different proteins are involved in cross-linking across these cell types.