STAT 1 binds to the LPL promoter in vitro
Abstract
Interferon-γ (IFNγ) has been shown to decrease the expression and activity of lipoprotein lipase (LPL). Hence, we searched for IFNγ sensitive binding sites within the murine LPL promoter. A region of the LPL promoter was identified that specifically binds nuclear, but not cytosolic, extracts isolated from IFNγ-treated 3T3-L1 adipocytes. EMSA analysis revealed that two protein complexes bind to this site within the LPL promoter and supershift analysis demonstrated that both of these complexes contained STAT 1 proteins. In addition, we have shown that this effect is specific for IFNγ, since LIF treatment, which also induces STAT 1, did not confer binding to this site. Interestingly, binding to this site within the LPL promoter could be effectively competed with a STAT 1 binding site that we previously identified in the PPARγ2 promoter. Also, IFNγ treatment resulted in decreased levels of LPL protein. In summary, we have identified a STAT 1 binding site within the murine LPL promoter which likely plays a role in the IFNγ induced decrease of LPL expression. © 2003 Elsevier Inc. All rights reserved.