tokens: In the IGR - N - 91 cell line , where p53 harbors two contiguous sets of exons 7 - 9 , spanning the DBD and oligomerization domain , it is interesting to note that the yeast colonies were predominantly white ( Figure 4B , dish b ) with the split 5 ' and the split 3 ' assay ( 96 and 87 % of white colonies , respectively ) This suggests that the cells express a binding ability that is specific to wild - type p53 rather than mutated p53 ( Table 2 ) .