Spin-column isolation of DNA-protein interactions from complex protein mixtures for AFM imaging

Applications of atomic Force microscopy (AFM) to investigate structural-fun ctional interactions between DNA and proteins, at the molecular level, shou ld prove valuable for gaining a better understanding of gene expression. Sp ecific genomic DNA-protein interactions occur within a sea of intracellular proteins. Successful AFM imaging requires isolating the specific DNA-prote in complex free of background protein contamination. Using spin-column chro matography. we report the successful isolation and AFM imaging of transcrip tion factor DNA complexes from DNA molecules incubated with crude cell lysa tes. This method should be applicable for the isolation and imaging of othe r specific DNA-protein complexes pertinent to functional genomic research. (C) 2001 Elsevier Science B.V. All rights reserved.