Asymmetric cell divisions produce new cell types during animal development. Studies in Caenorhabditis elegans have identified major signal-transduction pathways that determine the polarity of cell divisions. How these relatively few conserved pathways interact and what modulates them to ensure the diversity of multiple tissue types is an open question. The Wnt/β-catenin asymmetry pathway governs polarity of the epidermal T seam cell in the C. elegans tail. Here, we show that the asymmetry of T-seam-cell division and morphogenesis of the male sensory rays require NHR-25, an evolutionarily conserved nuclear receptor. NHR-25 ensures the neural fate of the T-seam-cell descendants in cooperation with the Wnt/β-catenin asymmetry pathway. Loss of NHR-25 enhances the impact of mutated nuclear effectors of this pathway, POP-1 (TCF) and SYS-1 (β-catenin), on T-seam-cell polarity, whereas it suppresses the effect of the same mutations on asymmetric division of the somatic gonad precursor cells. Therefore, NHR-25 can either synergize with or antagonize the Wnt/β-catenin asymmetry pathway depending on the tissue context. Our findings define NHR-25 as a versatile modulator of Wnt/β-catenin-dependent cell-fate decisions.

We thank Hitoshi Sawa for providing materials and for sharing unpublished information. Strains from Hiroshi Kagoshima, Maureen M. Barr, the C. elegans Genetics Center and the International C. elegans Gene Knockout Consortium are greatly appreciated. We thank Yinhua Zhang for useful suggestions. This work was supported by projects 204/07/0948 and 204/09/H058 from the Czech Science Foundation, 2B06129 from the Czech Ministry of Education, Z60220518 from the Institute of Parasitology, and GM56339 and P20RR016475 from the NIH National Center for Research Resources (NCRR). Deposited in PMC for release after 12 months.

You do not currently have access to this content.