May participate in the regulation of cell proliferation through the E2F/RB pathway. May be involved in molecular regulation of hematopoietic stem cells and progenitor cell lineage commitment and differentiation (By similarity). Highest levels of expression in the pancreas, thymus, testis, spleen, liver, placenta and leukocytes. Relatively low levels in the lung, kidney, prostate, ovary, small intestine and colon. Hardly detectable, if at all, in the brain, skeletal muscle and heart. By E2F1.