The mouse C-reactive protein (CRP) gene is expressed in response to IL-1 but not IL-6.

C-Reactive protein (CRP) is a minor acute phase reactant (APR) in the mouse, whereas CRP is the prototypical and one of the major positive APRs in all other mammals. MoCRP gene expression was tissue specific for the liver and induced by culture supernatants of LPS-activated macrophages. MoCRP gene expression by isolated hepatocytes in culture increased c, 3-fold in response to interleukin (IL)-1, but not IL-6. IL-6 is the most potent inflammatory cytokine for the induction of human CRP and many other APRs. By contrast, gene expression of the major APR of the mouse, serum amyloid P-component (SAP), a structural homologue of CRP, increased in response to either IL-1 or IL-6 under the same conditions. The region containing two potentially IL-1 responsive C/EBP elements in the moCRP gene failed to respond to IL-1 when a pCAT construct containing the elements was transfected into Hep 3B2 hepatoma cells. Therefore, IL-1 may influence the expression of the moCRP gene at the post-transcriptional rather than at the transcriptional level. The findings suggest that moCRP may be a minor APR because of the limited response of the gene to inflammatory cytokine signals.