Isolation and characterization of a novel gene, xMADML, involved in Xenopus laevis eye development

We have identified Xenopus MADM-like (xMADML), a Xenopus laevis gene related to the murine MADM and the human NRBP genes. xMADML is expressed throughout early development and is expressed most strongly in the developing lens and more weakly in the retina and other anterior tissues. We demonstrate that disruption of xMADML translation by means of morpholino injection results in impaired retina and lens development. Reciprocal transplantation of the presumptive lens ectoderm between morpholino-injected embryos and those injected solely with a dextran lineage tracer demonstrates that xMADML is necessary in both the lens and the retina for correct development of these eye tissues. Analysis of gene expression after knockdown of xMADML revealed significant alterations in the expression of some genes, including Pax6, xSix3, Sox2, and Sox3, suggesting that xMADML plays a role in regulating gene expression during development of the eye. This investigation is the first in vivo study examining the developmental role of this novel gene and reveals an important role of xMADML in eye tissue development and differentiation.