Recovery of liver mass without proliferation of hepatocytes after partial hepatectomy in Skp2-deficient mice.

The abundance of p27(Kip1), an inhibitor of cell proliferation, is determined by Skp2-dependent proteolysis, the deregulation of which is associated with cancer progression. Lack of Skp2 results in p27(Kip1) accumulation as well as enlargement and polyploidy of hepatocytes. The role of Skp2 in cell growth and proliferation was investigated in Skp2-deficient mice subjected to partial hepatectomy. Skp2(-/-) mice exhibited restoration of liver mass without cell proliferation; rather, hepatocytes increased in size, an effect that was accompanied by increased polyploidy and p27(Kip1) accumulation. Lack of Skp2 thus impairs hepatocyte proliferation, which is compensated for by cellular enlargement, during liver regeneration.