IMMUNE FACTOR GAMBIF1, A NEW REL FAMILY MEMBER FROM THE HUMAN MALARIAVECTOR, ANOPHELES-GAMBIAE

A novel rel family member, Gambif1 (gambiae immune factor 1), has been cloned from the human malaria vector, Anopheles gambiae, and shown to be most similar to Drosophila Dorsal and Dif. Gambif1 protein is tran slocated to the nucleus in fat body cells in response to bacterial cha llenge, although the mRNA is present at low levels at all developmenta l stages and is not induced by infection, DNA binding activity to the kappa B-like sites in the A.gambiae Defensin and the Drosophila Dipter icin and Cecropin promoters is also induced in larval nuclear extracts following infection, Gambif1 has the ability to bind to kappa B-like sites in vitro, Co-transfection assays in Drosophila mbn-2 cells show that Gambif1 can activate transcription by interacting with the Drosop hila Diptericin regulatory elements, but is not functionally equivalen t to Dorsal in this assay, Gambif1 protein translocation to the nucleu s and the appearance of kappa B-like DNA binding activity can serve as molecular markers of activation of the immune system and open up the possibility of studying the role of defence reactions in determining m osquito susceptibility/refractoriness to malaria infection.