CITED2 was initially identified as a potential transcriptional activator with significant homology to MSG1, a melanocyte-specific nuclear protein. CITED2 interacts with the histone acetyltransferase p300/CBP and acts as a coactivator to several DNA-binding transcription factors such as HIF-1 and AP-2. CITED2 also controls proliferation of mouse embryonic fibroblasts via the polycomb group genes Bmi-1 and Mel18 and the tumor suppressor Ink4a/Arf. CITED2 has also been found to be an essential regulator of adult hematopoietic stem cells (HSCs), with conditional deletion of CITED2 in the adult mouse resulting in the loss of HSCs, multilineage bone marrow failure and increased lethality.