XB-ART-44122PLoS One January 1, 2011; 6 (10): e26533.
Expression of Wnt signaling components during Xenopus pronephros development.
The formation of the vertebrate kidney is tightly regulated and relies on multiple evolutionarily conserved inductive events. These are present in the complex metanephric kidney of higher vertebrates, but also in the more primitive pronephric kidney functional in the larval stages of amphibians and fish. Wnts have long been viewed as central in this process. Canonical β-Catenin-dependent Wnt signaling establishes kidney progenitors and non-canonical β-Catenin-independent Wnt signaling participate in the morphogenetic processes that form the highly sophisticated nephron structure. While some individual Wnt signaling components have been studied extensively in the kidney, the overall pathway has not yet been analyzed in depth. Here we report a detailed expression analysis of all Wnt ligands, receptors and several downstream Wnt effectors during pronephros development in Xenopus laevis using in situ hybridization. Out of 19 Wnt ligands, only three, Wnt4, Wnt9a and Wnt11, are specifically expressed in the pronephros. Others such as Wnt8a are present, but in a broader domain comprising adjacent tissues in addition to the kidney. The same paradigm is observed for the Wnt receptors and its downstream signaling components. Fzd1, Fzd4, Fzd6, Fzd7, Fzd8 as well as Celsr1 and Prickle1 show distinct expression domains in the pronephric kidney, whereas the non-traditional Wnt receptors, Ror2 and Ryk, as well as the majority of the effector molecules are rather ubiquitous. In addition to this spatial regulation, the timing of expression is also tightly regulated. In particular, non-canonical Wnt signaling seems to be restricted to later stages of pronephros development. Together these data suggest a complex cross talk between canonical and non-canonical Wnt signaling is required to establish a functional pronephric kidney.
PubMed ID: 22028899
PMC ID: PMC3197532
Article link: PLoS One
Genes referenced: celsr1 celsr2 celsr3 dvl1 dvl2 dvl3 fzd1 fzd10 fzd2 fzd3 fzd4 fzd5 fzd6 fzd7 fzd8 fzd9 gnl3 prickle1 prickle2 prickle3 ror2 ryk vangl1 vangl2 wnt1 wnt10a wnt10b wnt11 wnt11b wnt16 wnt2b wnt3a wnt4 wnt5a wnt5b wnt6 wnt7a wnt7b wnt7c wnt8a wnt8b wnt9a wnt9b wnt9b.2
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