Investigation of surface oligonucleotide-binding proteins of eucaryotic cells by affinity modification with reactive oligonucleotide derivatives

Interactions between oligodeoxyribonucleotides (ODN) with different sequences and cell proteins were examined using the affinity modification by ³²P]-labeled reactive oligonucleotide derivatives. 3"-Terminal ribouridine oxidized with sodium periodate, 4-(N-2-chloroethyl-N-methyl)amino]benzylamine, and the maleimide residue were used as reactive groups. All the compounds used are specific reagents. The set of the discovered nucleic acid-binding (NA-binding) proteins depends on the chemical properties of the affinity reagent. The presence of the hydrophobic group at the 5"-terminus of the ODN molecule is the key factor determining the variety of the discovered NA-binding proteins. The cells of different origin (A431, HeLa, KB, MCF-7, Hap-2, K562, Cos-7, NIH/3T3, human-lung primary epithelial cells, and porcine kidney primary cells) are characterized by the same set of NA-binding proteins whose affinity modifications depends on the conditions of incubation of oligonucleotides with the cells. Treatments of cells disturbing the integrity of the cellular membrane (scrapping, treatment with trypsin, or cell permeabilization with streptolysin O or saponin), disrupt interactions between NA-binding proteins from native cells and ODN.