CREBBP and anemia: However, it remained unclear from that experiment whether other blood cell defects seen in p300KIX/KIX mice, such as anemia and decreased B cell counts, depend on a genetic interaction between c-Myb and p300. Based on the phenotypic overlap between p300+/KIX;CBPKIX/KIX triple-KIX, p300KIX/KIX and various c-Myb mutant mice (Table 1), we hypothesized that additional blood lineages require the interaction of the KIX domain and c-Myb, and that CBP, as well as p300, participates in a genetic interaction with c-Myb.