Related Experiment Video
Updated: Aug 15, 2026

Studying Cell Cycle-regulated Gene Expression by Two Complementary Cell Synchronization Protocols
Published on: June 6, 2017
Tissue-specific regulation of Chk1 expression by p53
1Department of Medicine, Vancouver Hospital and Health Sciences Centre, V6H 3Z6, Canada.
Abstract:
The regulation of Chk1, a critical protein kinase involved in G(2) phase arrest, has been a subject of recent research. Chk1 phosphorylates tumor suppressor p53 at multiple sites, while p53 has been shown to downregulate Chk1 expression under stress conditions in vitro, suggesting negative feedback between the two checkpoint proteins. Using the p53 knockout mouse model, we demonstrate by Western blot and immunohistochemistry that mChk1 expression is induced in spleen, thymus, and dermal fibroblasts and is reduced in lung and testis in p53(-/-) mice compared to p53(+/+) controls. The mChk1 protein was undetectable in heart, kidney, and skin, whereas abundant expression was observed in brain and liver in both p53(+/+) and p53(-/-) mice. These data indicate that p53 regulates Chk1 expression in a tissue-specific manner.
Related Concept Videos
Negative Regulator Molecules
DNA Damage can Stall the Cell Cycle
Inhibition of Cdk Activity
Abnormal Proliferation
Interactions Between Signaling Pathways
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
DNA Damage Can Stall the Cell Cycle

