Survival signals

Signalling by the c-Jun N-terminal kinase (JNK) pathway has been implicated in the cellular response to stress and the induction of apoptosis. In an Advanced Online Publication in Nature Genetics, Hess et al. demonstrate a clear role for JNK1 in cell survival (Nature Genetics, 5 August 2002, doi:10.1038/ng946). They used knockout mice lacking the Mapk8/jnk1 gene to investigate the role of JNK signalling in B-cell transformation induced by the leukemogenic oncogene BCR-ABL. They observed reduced BCR-ABL transformation of pre-B cells in vitro in the absence of JNK1, and altered leukemia in vivo. JNK1 deletion resulted in decreased cell survival and reduced expression of the anti-apoptotic Bcl-2 protein. Restoring Bcl-2 expression, using transgenic animals, restored B-cell leukemogenesis.