Normal Development of Mice Lacking Metablastin (P19), a Phosphoprotein Implicated in Cell Cycle Regulation

Metablastin, also called P19, stathmin, prosolin, Lap18, and oncoprotein18, is a highly conserved cytosolic protein that undergoes extracellular factor- and cell cycle-regulated serine phosphorylation and developmentally regulated expression in mammals. It has been implicated in a variety of cellular functions including growth and differentiation, and recent evidence suggests an involvement in cell cycle control. To explore its potential role in mammalian development, we have disrupted the gene encoding metablastin by gene targeting in mice. The metablastin null mutants have no overt phenotype regarding development, growth rate, behavior, T cell maturation, or fertility and do not exhibit an increased predisposition to tumors. SCG10, a protein closely related in structure to metablastin, shows no compensatory up-regulation in metablastin-/- mice. Although the data suggest that metablastin is not essential for mammalian development, the knockout mice should prove valuable in exploring the role of this protein in cell cycle regulation.