TJP1 and infection: However, occludin expression was significantly decreased from day 3 after infection, continually declined at later time-points, and was barely detectable in affected seminiferous tubules on day 14. A similar time-dependent pattern of decreasing expression was found for tight junction adaptor protein zonula occludens-1 (ZO-1), the cell-skeleton protein filamentous actin (F-actin), gap junction protein connexin-43 (CX-43), and adhesion junction proteins (β-catenin and N-cadherin).