Figure 2. Modulation of FBH1 expression changes the DSB signaling response in melanoma cells. (A) SK-MEL2 cells infected with lentiviruses encoding shRNAs targeting either LacZ or FBH1 mRNA were treated with hydroxyurea (HU) for 24 h. After harvesting, cells were fractionated into soluble and chromatin fractions, and the latter were immunoblotted for the indicated proteins. (B) SK-MEL28 cells stably infected with either an empty virus (MSCV) or a virus expressing FBH1 were treated with HU for the indicated times. After harvesting, cells were fractionated into soluble and chromatin fractions, and lysates were immunoblotted as indicated.