FIGURE 8.

Mdb1 focus formation requires both subunits in a dimer to possess the γH2A-binding ability. A, co-expression of Mdb1(105–624)-GBP rescued the ability of Mdb1(105–624)-GFP to form nuclear foci, and this rescue was abolished when the K434M mutation was introduced into one or both proteins. Cells were imaged 30 min after exposure to 36 Gy of IR. The strains used were DY23263, DY24110, DY24112, and DY24114. Bar, 5 μm. B, quantitation of the results shown in A. Approximately 200 nuclei were examined for each sample.