Epithelial polarization modulates gene expression. The transcription factor zonula
occludens 1 (ZO-1)–associated nucleic acid binding protein (ZONAB) can shuttle between
tight junctions and nuclei, promoting cell proliferation and expression of cyclin D1 and
proliferating cell nuclear antigen (PCNA), but whether it also represses epithelial
differentiation is unknown. Here, during mouse kidney ontogeny and polarization of proximal
tubular cells (OK cells), ZONAB and PCNA levels decreased in parallel and inversely …