Transfection of Cdk5 together with p35NcK5a induces a monocytic phenotype.

(A) Undifferentiated HL60 cells were transfected by electroporation with the pEGFPN1 plasmid, which can express the green fluorescent protein (GFP), together with p35Nck5a, or (B) with a plasmid expressing GFP-Cdk5 fusion protein alone, or (C) cotransfected with pEGFPN1-Cdk5 together with a plasmid expressing p35Nck5a. The transfected cells were incubated for 24 hours, then stained with PE-labeled antibody to CD14, a marker of myeloid monocytic phenotype, and examined under a fluorescent microscope using different filters. The green color (FITC filter 488-509 nm) indicates the expression of the GFP protein, whereas the red color (rhodamine filter 504-534 nm) shows monocytic differentiation. Note that transfection of Cdk5 and p35Nck5a together induces the monocytic marker. These experiments were repeated 4 times. Magnification, × 200.