FIG. 9.

Human DMPK A promotes mitochondrial clustering at perinuclear sites. The fraction of N2A and HeLa cells containing clustered mitochondria was determined after transient transfection with vectors encoding mouse or human DMPK isoforms A and C. Mitochondria were regarded as clustered when virtually all cytochrome c oxidase-positive mitochondria aggregated near the nucleus. The extent of clustering induced by hDMPK A in N2A cells is probably underestimated because many transfected cells showed an apoptosis-like appearance and therefore were excluded from the assay (asterisk). A minimum of 100 cells was analyzed for each cell type and each DMPK expression vector. Subcellular localization of DMPK isoforms is indicated.