Chromium (Cr) is a human carcinogen and a potent DNA damaging agent, I
ncubation of DNA with CrCl3 resulted in dose-dependent binding of Cr t
o DNA and, at concentrations >20 mu M, altered the electrophoretic mob
ility of a 100 bp oligonucleotide. We also demonstrate that high mobil
ity group (HMG) proteins 1 and 2 bind Cr-damaged DNA (Cr-DNA). Protein
binding was lesion density-dependent, with maximal binding to DNA tre
ated with 100 mu M CrCl3. HMG2 binds to Cr-DNA with a calculated K-d O
f similar to 10(-9) M. These proteins also bound DNA obtained from chr
omate-treated cells, These results suggest that the covalent attachmen
t of Cr to DNA induces alterations in DNA structure which are recogniz
ed by HMG1 and HMG2 Therefore, these proteins may function as Cr-damag
ed DNA recognition proteins in vivo and as a consequence of binding, m
ay play a role in directing the cellular response to Cr-DNA adduct for
mation.