Liver zonation occurs through a beta-catenin-dependent, c-Myc-independent mechanism

Zoé D Burke ¹, Karen R Reed , Toby J Phesse

⁰Centre for Regenerative Medicine, Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, UK.

Gastroenterology +

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March 10, 2009

View abstract on PubMed

Summary

Liver zonation of ammonia metabolizing enzymes is dependent on beta-catenin, not c-Myc. This study clarifies the Wnt pathway

Area Of Science

Hepatology
Molecular Biology
Biochemistry

Background

Hepatic zonation, the spatial organization of liver cells, is crucial for metabolic processes.
The Wnt signaling pathway is implicated in regulating hepatic zonation.
Key Wnt pathway components' roles in zonation of ammonia metabolism require elucidation.

Purpose Of The Study

To investigate the role of Adenomatous Polyposis Coli (Apc), beta-catenin, and c-Myc in liver zonation.
To determine their impact on the expression of ammonia metabolizing enzymes.

Main Methods

Conditional gene deletion of Apc, beta-catenin, and c-Myc in mouse livers.
Analysis of periportal and perivenous hepatocyte markers using PCR, Western blotting, and immunohistochemistry.

Main Results

Loss of Apc led to widespread nuclear beta-catenin and glutamine synthetase (GS) expression, reducing carbamoylphosphate synthetase I (CPS I).
Beta-catenin deletion resulted in loss of GS and increased CPS I expression.
c-Myc deletion did not affect the established zonation patterns.

Conclusions

Hepatic zonation of ammonia metabolizing enzymes is regulated by the Wnt pathway.
Beta-catenin is essential for maintaining this zonation.
The Wnt pathway's role in hepatic zonation is independent of c-Myc.

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