Subcellular localization of protein kinase CK2 subunits in onion cells. Confocal microscopy images of onion cells transfected with CK2α1-GFP (A), CK2α2-GFP (B), CK2α3-GFP (C), CK2β1-GFP (D), CK2β2-GFP (E), and CK2β3-GFP (F). (Left) General views of transfected cells (×20). (Center) Detail of fluorescent cell nucleus (×60). (Right) View of the same nucleus under Nomarsky optics. (G Upper) Confocal microscopy images of onion cells transfected with CK2α2-GFP and CK2β3-RFP, respectively. (Lower) Onion cell cotransfected with CK2α2-GFP/CK2β3-RFP.