SC1is a putative transactivating factor, with expression beginning at the late G1/S boundary in dividing cells. It contains a FHA association (Forkhead) domain, which may serve as a nuclear signaling domain or as a phosphoprotein binding domain.SC1is expressed in mouse and human islets, with increasing mRNA expression in nondiabetic obesity. The expression of SC1 is correlated with Beta-cell mass expansion, suggesting that it may be a transcriptional regulator of Beta-cell mass.