Int. J. Dev. Biol. 56: 239 - 244 (2012)
doi: 10.1387/ijdb.113482mt
© UPV/EHU Press

xCOUP-TF-B regulates xCyp26 transcription and modulates retinoic acid signaling for anterior neural patterning in Xenopus

Misaki Tanibe1, Sho-Ichi Ishiura1, Makoto Asashima1,2 and Tatsuo Michiue*,1

1Department of Life Sciences (Biology), Graduate School of Arts and Sciences, The University of Tokyo and 2Research Center for Stem Cell Engineering, National Institute of Advanced Industrial Science and Technology (AIST), Japan

ABSTRACT Early embryogenesis in Xenopus development depends on correct anterior-posterior (A-P) neural patterning during gastrulation. It is known that high levels of retinoic acid (RA), a major intracellular signaling molecule, determine posterior cell fate, also reflecting an involvement in A-P neural patterning. Here we show that the known RA effector, xCOUP-TF, plays important roles in head development of Xenopus embryo. xCOUP-TF-B injection into the dorsal region of embryos induced formation of an abnormal head with small eyes. Analysis of brain marker gene expression revealed that xCOUP-TF-B injection induced slight anteriorization in embryos and attenuated the effects of RA treatment. This anteriorization effect was enhanced when xCOUP-TF-B was co-injected with xCyp26A or xCyp26C, which are known RA metabolizing factors. Furthermore, xCOUP-TF-B injection enhanced xCyp26A/C transcription. Together, these results suggest that xCOUP-TF and xCyp26 are both regulated by Wnt signaling, and cooperatively function in RA signaling to affect A-P neural patterning.

Keywords:

Xenopus, retinoic acid, Wnt signaling, A-P patterning

*Corresponding author e-mail: tmichiue@bio.c.u-tokyo.ac.jp