Transcriptional regulation of complement genes.

Complement is a major effector system of host defense against invading pathogens. The recently completed cloning and structural characterization of almost all complement genes has allowed investigation of their regulation at the molecular level. Transcription of most complement genes is accelerated during the acute-phase response that follows tissue injury. Mechanisms regulating transcription of other acute-phase proteins have been elucidated during recent years. The main mediators of acute phase proteins are IL-1- and IL-6-type cytokines. These cytokines and IFN gamma induce transcription of complement genes in the liver and in several extrahepatic sites. Consensus elements binding transcription factors activated by these cytokines have been identified in the promoters of several complement genes. However, only a few complement promoters have been characterized functionally. Structural analysis has indicated that TATA-less promoters are common among complement genes. However, no shared initiator elements (Inr) have been identified so far.