Recently, significant advances have been made in the analysis of mesoderm induction, one of the first inductive interactions in vertebrate development. In this article, I review these advances in the context of earlier work on the subject and go on to discuss what problems remain and how they might be approached. I shall concentrate on cell biological and embryological aspects of mesoderm induction rather than on the transcriptional control of genes which are activated in response to induction. This work has recently been reviewed elsewhere (Gurdon et al. 1989).
Mesoderm induction probably occurs during the development of all vertebrates (Nieuwkoop et al. 1985; Smith, 1988) but the phenomenon has been most extensively studied in the Amphibia. This is for several reasons: amphibian embryos are large, making micro-dissection relatively easy; they are accessible to experimental manipulation at all developmental stages, from oogenesis to adulthood;...
