Reprimo, a new candidate mediator of the p53-mediated cell cycle arrest atthe G(2) phase

A novel gene, Reprimo, in which induction in cells exposed to X-irradiation is dependent on p53 expression, has been isolated. Ectopic p53 expression results in the induction of its mRNA. Reprimo is a highly glycosylated prot ein and, when ectopically expressed, it is localized in the cytoplasm and i nduces G(2) arrest of the cell cycle. In the arrested cells, both Cdc2 acti vity and nuclear translocation of cyclin El are inhibited, suggesting the i nvolvement of Reprimo in the Cdc2.cyclin B1 regulation pathway. Thus, Repri mo may be a new member involved in the regulation of p53-dependent G(2) arr est of the cell cycle.