Disease relevance of Def

• The gene coding for the only known peptide with high activity against Gram-positive bacteria, Defensin, is regulated by both pathways [1].

High impact information on Def

• The results show that the presence of Dif without Dorsal is sufficient to mediate the induction of drosomycin and defensin [2].
• DNA binding activity to the kappaB-like sites in the A.gambiae Defensin and the Drosophila Diptericin and Cecropin promoters is also induced in larval nuclear extracts following infection [3].
• In vitro-translated protein from the Rel-only construct specifically binds to the kappa B motif from Drosophila cecropin A1 and Aedes defensin genes [4].
• We identify a gene, psidin, that encodes a lysosomal protein required in the blood cells for both degradation of engulfed bacteria and activation of fat-body Defensin [5].
• Insect immunity. Isolation from the lepidopteran Heliothis virescens of a novel insect defensin with potent antifungal activity [6].

Biological context of Def

• Transcriptional profiles indicate that the Drosophila defensin gene is induced by bacterial challenge with acute-phase kinetics [7].
• Recently, we have provided proof of this concept by engineering stable transformant lines of Aedes aegypti mosquito, in which the regulatory region A. aegypti vitellogenin (Vg) gene activates high-level fat body-specific expression of a potent anti-bacterial factor, defensin, in response to a blood meal [8].

Anatomical context of Def

• The cecropin type of linear peptides without cysteine were found first in insects, whilst the defensin type with three disulphide bridges were found in rabbit granulocytes [9].

Associations of Def with chemical compounds

• The corresponding Cysteine Stabilized alpha beta (CS alpha beta) motif, which was found in other defense proteins such as the antibacterial insect defensin A, short- and long-chain scorpion toxins, as well as in plant thionins and potent antifungal plant defensins, appears as remarkably persistent along evolution [10].

References