Pbx genes are required in Xenopus lens development.

Development of the vertebrate eye is dependent on multiple tissue interactions and distinct sets of transcription factors and signalling molecules. The latter are thought to be FGF8 and BMP4, proteins secreted from the neural plate to induce lens formation in the overlying ectoderm. Here we show that the Pbx transcription factor plays a crucial role in this process, as it is required for FGF8 expression in the neural plate and is thus part of the complex hierarchy of genes involved in lens induction.