Nuclear accumulation of β-catenin and transcription of downstream genes are regulated by zygotic Wnt5α and maternal Dsh in ascidian embryos
Version of Record online: 1 MAY 2007
Copyright © 2007 Wiley-Liss, Inc.
Special Issue: Special Focus on Segmentation
Volume 236, Issue 6, pages 1570–1582, June 2007
How to Cite
Kawai, N., Iida, Y., Kumano, G. and Nishida, H. (2007), Nuclear accumulation of β-catenin and transcription of downstream genes are regulated by zygotic Wnt5α and maternal Dsh in ascidian embryos. Dev. Dyn., 236: 1570–1582. doi: 10.1002/dvdy.21169
- Issue online: 16 MAY 2007
- Version of Record online: 1 MAY 2007
- Manuscript Accepted: 26 MAR 2007
- MEXT. Grant Numbers: 13044003, 16770161, 18770200
- JSPS. Grant Number: 16107005
- Toray Science and Technology Grant
- nuclear transport;
- ascidian embryo
Nuclear β-catenin plays crucial roles in the establishment of the embryonic axis and formation of mesendoderm tissues in ascidians and other animals. However, the cue responsible for nuclear accumulation of β-catenin in the vegetal hemisphere is still unknown in ascidians. Here, we investigated the roles of Wnt5α and Dsh in the nuclear accumulation of β-catenin and activation of its downstream genes in the ascidian Halocynthia roretzi. Wnt5α knockdown embryos lost nuclear accumulation of β-catenin at the 64-cell stage but not at the 32-cell stage, and expression of Hr-lim, one of the targets of β-catenin, was impaired in the anterior region of the embryo. Zygotic Wnt5α expression in the anterior-vegetal blastomeres was primarily responsible for these defects. Dsh knockdown showed no effect on nuclear localization of β-catenin, but inhibited Hr-lim expression in the posterior region. These results suggest that maintenance of nuclear Hr-β-catenin after the 64-cell stage is regulated by zygotic Hr-Wnt5α, and that expression of its target genes is modulated by both Hr-Wnt5α and Hr-Dsh. Our results also highlight the importance of nuclear accumulation of β-catenin up to the 32-cell stage through a still unclarified mechanism. Developmental Dynamics 236:1570–1582, 2007. © 2007 Wiley-Liss, Inc.