Targeted disruption of the MKK4 gene causes embryonic death, inhibition of c-Jun NH2-terminal kinase activation, and defects in AP-1 transcriptional activity
Graduate School of Biomedical Sciences; Program in Molecular Medicine
Life Sciences | Medicine and Health Sciences
MKK4 is a member of the mitogen-activated protein kinase kinase group of dual specificity protein kinases that functions as an activator of the c-Jun NH2-terminal kinase (JNK) in vitro. To examine the function of MKK4 in vivo, we investigated the effect of targeted disruption of the MKK4 gene. Crosses of heterozygous MKK4 (+/-) mice demonstrated that homozygous knockout (-/-) animals die before embryonic day 14, indicating that the MKK4 gene is required for viability. The role of MKK4 in JNK activation was examined by investigation of cultured MKK4 (+/+) and MKK4 (-/-) cells. Disruption of the MKK4 gene blocked JNK activation caused by: (i) the mitogen-activated protein kinase kinase kinase MEKK1, and (ii) treatment with anisomycin or heat shock. In contrast, JNK activation caused by other forms of environmental stress (UV-C radiation and osmotic shock) was partially inhibited in MKK4 (-/-) cells. Regulated AP-1 transcriptional activity, a target of the JNK signal transduction pathway, was also selectively blocked in MKK4 (-/-) cells. Complementation studies demonstrated that the defective AP-1 transcriptional activity was restored by transfection of MKK4 (-/-) cells with an MKK4 expression vector. These data establish that MKK4 is a JNK activator in vivo and demonstrate that MKK4 is an essential component of the JNK signal transduction pathway.
DOI of Published Version
Proc Natl Acad Sci U S A. 1997 Apr 1;94(7):3004-9.
Proceedings of the National Academy of Sciences of the United States of America
Yang D, Tournier C, Wysk MA, Lu H, Xu J, Davis RJ, Flavell RA. (1997). Targeted disruption of the MKK4 gene causes embryonic death, inhibition of c-Jun NH2-terminal kinase activation, and defects in AP-1 transcriptional activity. Morningside Graduate School of Biomedical Sciences Student Publications. https://doi.org/10.1073/pnas.94.7.3004. Retrieved from https://escholarship.umassmed.edu/gsbs_sp/749