Meeting report: 11th International Mouse Genome Conference

Modulation of Dishevelled and Vangl2 by all-trans-retinoic acid in the developing mouse central nervous system and its relationship to teratogenesis

The response to exposure to all-trans-retinoic acid (RA) during embryogenesis varies from physiologic to severe teratogenic effects and is dependent upon the dose and the stage of development in all species. Vangl2 and Dishevelled genes play key roles in establishing planar cell polarity and regulating convergent extension movements during the neurula period. The effects of RA-mediated teratogenesis might be due to its misregulation of Vangl2 and Dishevelled genes. The aim of this study is to monitor the modulation of Vangl2 and Dishevelled in Kunming mouse embryos following maternal treatment with a single oral dose of 30 mg/(kg body weight) of RA during the neurula period. Exposure of 7.75 d embryos to RA induced characteristic morphological changes. The most obvious external effect was the failure of neural tube closure in the midbrain and forebrain regions in 10 d embryos, resulting in exencephaly in later embryos. RA treatment also led to a pronounced decrease of Vangl2 mRNA at 4 and 18 h and a pronounced increase at 66 h after maternal treatment, as detected by reverse transcription-polymerase chain reaction. Western blot analysis showed a marked decrease of Vangl2 protein at 18 and 42 h and a marked increase at 66 and 90 h after maternal treatment. Dishevelled1/2/3 mRNA was significantly down-regulated at 4 and 18 h and up-regulated at 42 h in the fetus after RA treatment, except for an up-regulation of Dishevelled3 at 66 h. The Dishevelled2 mRNA and its protein matched each other. These results hinted that Vangl2 and Dishevelled genes might take part in RA teratogenesis of mouse embryos.

Genetic models for non insulin dependent diabetes mellitus in rodents

Efforts to identify human genes with major effects on insulin resistance and type II diabetes have yet to be successful because of the technical difficulties associated with the analysis of complex traits in humans. Animal models, particularly the rodent models with their well developed genetic tools, and their genetic similarity to humans, offer an alternate approach to access genes important in the etiology of diabetes. This approach is validated by the remarkable progress that has been made in the identification and characterization of the genes mutated in five monogenic mouse models of obesity. Identification of these genes has led to new insights into the etiology of obesity and provided promising targets for therapeutic intervention. Arguably, genetic animal models could do the same for our understanding of diabetes. In this brief review, we introduce rodent models of type II diabetes and report on the state of their genetic analyses.