[Visualization of DNA segments, interacting with reactive oligonucleotide derivatives in interphase nuclei and metaphase chromosomes]. / Vizualizatsiia uchastkov DNK, vzaimodeistvuiushchikh s reaktsionnosposobnymi oligonukleotidov, v sostave interfaznykh iader i metafaznykh khromosom.

Reaction of (pdT)16 derivatives, bearing 4-(N-2-chloroethyl-N-methylamino)benzylphosphamide group on its 5' end and biotin on its 3' end with DNA in interphase nuclei and metaphase chromosomes has been investigated by fluorescence and electron microscopy. The result obtained evidence that in interphase nuclei DNA in active chromatin (nucleolus) is the most available for specific modification. In metaphase chromosomes the modified DNA regions are situated on the surface of chromosome.

[Interaction of photoactive oligothymidylate derivatives with HeLa cell chromatin]. / Vzaimodeistvie fotoaktivnykh proizvodnykh oligotimidilata s khromatinom kletok HeLa.

Photoactive derivatives of d(pT)16, bearing arylazide, nitroarylazide and perfluoroarylazide residues, were used for the complementary addressed modification of DNA and proteins in chromatin. As compared with alkylating derivatives, the photoactive compounds possess higher efficiency and specificity, and shorter incubation times which prevents nucleus from degradation. These reagents can therefore be used for identification of proteins located near to particular DNA regions in chromatin.

[Synthesis of oligodeoxyribothymidylate derivatives containing alkylating groups and residues of biotin, for directed modification of chromatin]. / Sintez proizvodnogo oligodezoksiribotimidilata, soderzhashchego alkiliruiushchuiu gruppu i ostatok biotina, dlia napravlennoi modifikatsii khromatina.

An oligodeoxythymidylate derivative bearing an alkylating group at the 5'-end and biotin at the 3'-end (RCl-(pdT)16-bio) was synthesized. This reagent alkylates polyA-tracts of DNA in HeLa nuclei specifically via complementary complexes with single-stranded segments of DNA and by the preliminary treatment of chromatin with S1-nuclease, since the reaction is inhibited by an excess of the corresponding free oligothymidylate. The reagent will be used to study the distribution of local unwinded parts of polyA-repeats of DNA in human chromatin by the electron microscopy.