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Development. 1999 Feb;126(3):505-16.

Defective liver formation and liver cell apoptosis in mice lacking the stress signaling kinase SEK1/MKK4.

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  • 1The Amgen Institute, Ontario Cancer Institute, and Departments of Medical Biophysics and Immunology, University of Toronto, Suite 706, Toronto, Ontario M5G 2C1, Canada.

Abstract

The stress signaling kinase SEK1/MKK4 is a direct activator of stress-activated protein kinases (SAPKs; also called Jun-N-terminal kinases, JNKs) in response to a variety of cellular stresses, such as changes in osmolarity, metabolic poisons, DNA damage, heat shock or inflammatory cytokines. We have disrupted the sek1 gene in mice using homologous recombination. Sek1(-/- )embryos display severe anemia and die between embryonic day 10.5 (E10.5) and E12.5. Haematopoiesis from yolk sac precursors and vasculogenesis are normal in sek1(-/- )embryos. However, hepatogenesis and liver formation were severely impaired in the mutant embryos and E11.5 and E12.5 sek1(-/- )embryos had greatly reduced numbers of parenchymal hepatocytes. Whereas formation of the primordial liver from the visceral endoderm appeared normal, sek1(-/-) liver cells underwent massive apoptosis. These results provide the first genetic link between stress-responsive kinases and organogenesis in mammals and indicate that SEK1 provides a crucial and specific survival signal for hepatocytes.

PMID:
9876179
[PubMed - indexed for MEDLINE]
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