S. Wolfl et al., IDENTIFICATION OF TRANSCRIPTIONALLY INDUCED Z-DNA SEGMENTS IN THE HUMAN C-MYC GENE, Biochimica et biophysica acta, N. Gene structure and expression, 1264(3), 1995, pp. 294-302
Using monoclonal antibodies against Z-DNA three AluI restriction fragm
ents of the human c-myc gene were previously found to form Z-DNA in ag
arose-embedded, metabolically active permeabilized nuclei. The formati
on of Z-DNA in these fragments was dependent on negative supercoiling
generated by transcription of the gene. Here we show which sequence el
ements of these three AluI restriction fragments adopt the Z conformat
ion upon negative supercoiling. The three fragments (Z1, Z2 and Z3) we
re inserted in a suitable plasmid vector. Z-DNA forming elements were
detected by comparing DEPC reactivity in relaxed circular and supercoi
led plasmid DNA. Z1 and Z3 each contained one major Z-DNA forming regi
on 20-25 nucleotides long, whereas Z2 contained two discrete regions 9
0 nucleotides apart one about 35 nucleotides the other about 20 nucleo
tides long.