Cloning and characterization of a putative inhibitor of melanization from Anopheles gambiae.
Phenoloxidases, including tyrosinases and laccases, are enzymes involved in the synthesis of melanin, a process that can be elicited during insect immune responses, cuticle maturation, wound healing and egg chorion development. We cloned a putative inhibitor of melanization (POI) from Anopheles gambiae on the basis of homology with a functionally characterized peptide from Musca domestica (Daquinag et al., Proc Natl Acad Sci USA 1995; 92: 2964-2968). The 335 amino acid protein predicted from the A. gambiae cDNA consists of five tandemly arranged inhibitor motifs. The A. gambiae POI gene was expressed in all mosquito stages from egg to adult. POI transcript levels were high in the fat body and were measurable but comparatively reduced in the midgut. The POI transcript level increased after wounding or Sephadex bead injection. Gene knockdown did not result in faster or more extensive bead melanization but did result in more extensive melanization of wound sites following a thoracic bead injection.
Shi
L
L
Department of Entomology, University of Wisconsin, Madison, Wisconsin 53706, USA.
Li
B
B
Paskewitz
S M
SM
D000595:Amino Acid Sequence; D000818:Animals; D000852:Anopheles / Q000235:genetics* / Q000276:immunology; D001483:Base Sequence; D018076:DNA, Complementary; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D019476:Insect Proteins / Q000737:chemistry; D008543:Melanins / Q000276:immunology; D008969:Molecular Sequence Data; D014442:Monophenol Monooxygenase / Q000502:physiology; D034622:RNA Interference; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D019476:Insect Proteins; D008543:Melanins; D014442:Monophenol Monooxygenase