Cecropia immunoresponsive factor, an insect immunoresponsive factor with DNA‐binding properties similar to nuclear‐factor KB

Abstract

The immune genes in Hyalophora cecropia contain an upstream sequence that is homologous to the binding site of the mammalian nuclear‐factor KB (NF‐KB). These genes are strongly induced by bacteria, lipopolysaccharides and 4β‐phorbol 12‐myristate 13‐acetate. Induction of the immune genes involves the activation of a DNA‐binding protein complex that we have named Cecropia immunoresponsive factor (CIF). CIF specifically recognizes the KB‐like DNA sequences in the promoter regions of the Cecropia immune genes. The DNA binding activity of CIF correlates well with the transcriptional induction of the immune genes. Competition assays show that CIF has a DNA binding specificity similar to mammalian NF‐KB. The two factors also share other characteristics, including the pattern of induction and the migration on the native gel.