How a tadpole metamorphoses into an adult is a captivating process. But how does the tail disappear? Now Chambon et al., on p. 1203, identify a gene network together with a cell-cell communication protein called Ci-sushi that are required for apoptosis in the regressing tail of Cionatadpoles. From a microarray expression profiling analysis of Cionalarvae treated with inhibitors of the MAP kinase and JNK pathways, which regulate apoptosis, these investigators uncovered a network of genes that show expression changes during metamorphosis. Ci-sushi, one such gene, is expressed in the tail epithelia and is downregulated by JNK inhibitors - when knocked down by a morpholino, tail cell death and regression are prevented. The authors propose that JNK activity in the CNS (which escapes cell death)causes apoptosis in adjacent cells through Ci-sushi activity. Given their basic chordate body plan, similar studies of Ciona larvae might shed light on the regulation of apoptosis in other vertebral column tissues, such as the neural tube.

© 2007.
2007