[Chromatin proteins in rat liver cells, interacting with reactive oligothymidylate derivatives]

Upon alkylation of the rat liver chromatin with a hexadecadeoxyribothymidylate derivative bearing 4-(N-2-chloroethyl-N-methylamino)benzylamine residue on the 5'-terminal phosphate two nonhistone proteins were modified under conditions of the reagent's forming complementary complexes with poly(A) sequences in DNA. The sequence-specific nature of the reaction is proved by the competition experiments: free oligothymidylate prevented the proteins from alkylation whereas arbitrary oligonucleotide did not. Modification with the reactive oligonucleotide derivatives can be used for the identification of proteins located in the vicinity of the specific open DNA regions in chromatin.