Turning the frog into a princely model

The frog, Xenopus laevis, has been at the forefront of experimental biology for over half a century. Indeed, the isolation of specific genes, detailed promoter analysis, and cloning of whole organisms were all first accomplished in frogs. One vital area in which the frog has lagged behind other organisms, however, is in the construction of germline transgenic animals for the stable and specific expression of introduced genes. This has limited the scope of analysis that researchers can perform on developmentally regulated genes. Although recent advances in transgenic technology have provided a partial remedy to this problem, the methods required are very laborious and demanding. In this issue, Sylvia Evans and colleagues describe a new and simple strategy to increase both the efficiency and fidelity of transgene expression in frog embryos. The new strategy will undoubtedly strengthen the experimental arsenal available to developmental biologists and also serve scientists who use frogs for the study of basic cell and molecular biological processes, such as RNA transport or chromatin remodeling. It also suggests that the frog could become a transgenic model to rival other vertebrates in functional genomics.