A HOT-SPOT FOR HYDROGEN PEROXIDE-INDUCED DAMAGE IN THE HUMAN HYPOXIA-INDUCIBLE FACTOR-1 BINDING-SITE OF THE PGK-1 GENE

Using ligation-mediated polymerase chain reaction to separately map th e distribution of induced oxidized bases and strand breaks along the h uman PGK1 promoter at nucleotide resolution, we previously described t he pattern of oxidative DNA damage induced in vitro by Cu(II)/ascorbat e/H2O2 [J. Biol. Chem. 270, 17633-17640 (1995)]. Here we report that t he pattern of in vivo base damage caused by H2O2 is almost identical t o that of the previously used in vitro system with the exception of tr anscription factor-associated footprints. An unusually strong positive footprint for both strand breaks and oxidized bases is associated wit h binding of the hypoxia-inducible transcription factor-1. Base damage at this footprint was 52-91% repaired in 24 h, which was similar to t he global base damage repair rate. However, strand breaks at this foot print were only 39-55% repaired in 24 h or approximately 100-fold slow er than the global strand break repair rate. (C) 1997 Academic Press.