Canonical Wnt Signaling Controls Proliferation of Retinal Stem/Progenitor Cells in Postembryonic Xenopus Eyes

Abstract

ABSTRACT

Wnt/β-catenin signaling is involved in the induction and maintenance of primitive hematopoiesis in the vertebrate embryo

“…a Dex-inducible Wnt-mimicking chimeric construct, LEFΔN-VP-16-GR, which we previously characterized (21). Embryos were treated with Dex to activate the construct and cultured for 2 h in the absence or presence of the translation-blocker, cycloheximide (CHX).…”

Loss of adenomatous polyposis coli (apc) results in an expanded ciliary marginal zone in the zebrafish eye

“…The Wnt/bcatenin pathway regulates stem cells, proliferation and differentiation in many other systems and also plays an important role in the regulation of the CMZ in vertebrates (Van Raay and Vetter, 2004;Van Raay et al, 2005). Studies in mice and chick have emphasized that activation of the Wnt pathway is required for the development of peripheral structures, such as the ciliary body and the iris, whereas other studies propose that the Wnt pathway also serves an important function in the maintenance of stem cells (Kubo et al, 2003(Kubo et al, , 2005Liu et al, 2007;Denayer et al, 2008;Kubo and Nakagawa, 2009). Here we propose that the zebrafish adenomatous polyposis coli (apc mcr ) mutation, which leads to constitutive up-regulation of the Wnt/b-catenin pathway, is an excellent model to decipher the roles of signaling pathways in the developing eye.…”

Direct control of Hoxd1 and Irx3 expression by Wnt/beta-catenin signaling during anteroposterior patterning of the neural axis in Xenopus

“…Identification of novel Wnt/    -catenin targets using transgenic Xenopus embryos In order to search for new target genes of the canonical Wnt/ -catenin pathway, we generated Xenopus laevis embryos that are transgenic for an optimized hormone-inducible, multicomponent Wnt pathway activating or repressing system (Denayer et al, 2008a, Deroo et al, 2004. These embryos constitute an ideal source for differential gene expression analysis since the integrated Wnt pathway interfering systems specifically intersect at the nuclear endpoint of the pathway.…”

“…In order to analyze which expression domains of the potential novel target genes were under control of Wnt/-catenin signaling, we performed whole mount in situ hybridization (WISH) analysis on embryos injected unilaterally at the 2-cell stage with synthetic RNA encoding either the Wnt-mimicking LefN-VP16-GR or the Wnt-inhibiting EnR-LefN-GR 755A , both previously characterized (Denayer et al, 2008a, Deroo et al, 2004. RNA encoding -galactosidase was coinjected as a tracer.…”

“…In order to identify patterning genes that are under direct control of Wnt/-catenin signaling, we deployed transgenic Xenopus laevis embryos that carry binary inducible constructs that can either inhibit or mimic Wnt/-catenin signaling (Denayer et al, 2008a, Deroo et al, 2004. We identified several homeodomaincontaining transcription factors that are induced by Wnt signaling in the neurula stage embryo.…”