SEQUENCE-SPECIFIC RECOGNITION OF THE HIV-1 LONG TERMINAL REPEAT BY DISTAMYCIN - A DNAASE-I FOOTPRINTING STUDY

Pharmacological modulation of the interaction between transcription fa ctors and target DNA sequences of cellular and viral genes could have important effects in the experimental therapy of a large variety of hu man pathologies. For instance, alteration of the DNA/protein interacti on might be among the molecular mechanisms of action of DNA-binding dr ugs, leading to an inhibition of the expression of genes involved in t he control of in vitro and in vivo growth of neoplastic eels and virus DNA replication. Natural oligopeptides, such as distamycin, are power ful inhibitors of the interaction between nuclear factors and target D NA sequences and, therefore, have been proposed as compounds retaining antibiotic, antineoplastic and antiviral properties. In this study we performed DNAase I footprinting analysis using a PCR product mimickin g a region of the long terminal repeat (LTR) of the human immunodefici ency type 1 (HIV-1) retrovirus. The data obtained suggest that distamy cin binds to different regions of the HIV-1 LTR depending on the DNA s equence. Electrophoretic mobility shift assays using both crude nuclea r extracts from the Jurkat T-lymphoid cell line and the recombinant pr oteins transcription factor IID and Sp1 suggest that distamycin differ entially inhibits the interaction of these two proteins with their spe cific DNA target sequences, in good agreement with the results obtaine d by DNAase I footprinting analysis.