Ae. Vinogradov et Jm. Rosanov, SOME PROPERTIES OF NEW DNA-SPECIFIC BISBENZIMIDAZOLE FLUOROCHROMES WITHOUT A PIPERAZINE RING, Biotechnic & histochemistry, 68(5), 1993, pp. 265-270
Three new bisbenzimidazole (BBI) compounds, which differ from Hoechst
33258 mainly by substitution of a N-dimethylaminopropylcarboxamide gro
up in place of the N-methylpiperazine ring, were studied for their DNA
- and AT-base pair specificity as well as for their ability to be quen
ched by incorporated 5-bromodeoxyuridine (BrdU). Each of them had DNA
binding specificity comparable to or greater than that of Hoechst 3325
8 and each had a greater specificity for AT-rich regions than did Hoec
hst 33258. The dependence of fluorescence of new dyes on the BrdU-inco
rporation into DNA is different from that of Hoechst 33258 and related
compounds with piperazine ring. The quenching effect is much weaker,
and two of the new compounds (BBI-1 and BBI-2) even show somewhat enha
nced binding (fluorescence) at lower concentrations. Certain BBI dyes
without piperazine ring may have some advantage over Hoechst for accur
ate DNA (AT-specific) measurements. The piperazine ring appears to pla
y an important role in the yet unknown mechanism of Hoechst quenching
by incorporated BrdU.