EVI5 is a cytokinesis‐associated protein with dynamic subcellular localization

Abstract

The EVI5 gene was originally identified in a screen for integration sites of ectopic viruses that gave rise to tumors in mice. The product of the gene is an 810 amino acids long ubiquitously expressed protein. It carries two functional domains, a Tre2/Bub2/Cdc16 (TBC) consensus sequence in the N‐terminal region, which is known to have a GTPase activating function, and an extensive coiled coil in the C‐terminal region. The goal of the present study was to elucidate the cellular localization and function of the EVI5 protein. A highly specific antibody against the C‐terminal section of the protein was used in an immunocytochemical analysis, and demonstrated that EVI5 is a nuclear protein, that is also present in the pericentriolar region of interphase cells. EVI5 is localized to the mitotic spindle during chromosome migration, and is also found in the midzone and midbody in late mitosis and during cytokinesis. Knockdown of EVI5 using siRNA results in a high incidence of binucleate cells with evidence for incomplete septation. The role of EVI5 in cytokinesis is further supported through the demonstration of its interaction with members of the chromosome passenger complex (INCENP, aurora B kinase and survivin). Taken together, these results suggest that EVI5 is involved in the completion of cytokinesis.This work was supported by NINDS grant NS35791 from the National Institutes of Health.