Identification and characterization of a novel peritrophic matrix protein, Ae-Aper50, and the microvillar membrane protein, AEG12, from the mosquito, Aedes aegypti.
Immuno-screening of an adult Aedes aegypti midgut cDNA expression library with anti-peritrophic matrix antibodies identified cDNAs encoding a novel peritrophic matrix protein, termed Ae. aegypti Adult Peritrophin 50 (Ae-Aper50), and the epithelial cell-surface membrane protein, AEG12. Both genes are expressed exclusively in the midguts of adult female mosquitoes and their expression is strongly induced by blood feeding. Ae-Aper50 has a predicted secretory signal peptide and five chitin-binding domains with intervening mucin-like domains. Localization of Ae-Aper50 to the peritrophic matrix was demonstrated by immuno-electron microscopy. Recombinant Ae-Aper50 expressed in baculovirus-infected insect cells binds chitin in vitro. Site-directed mutagenesis was used to study the role that cysteine residues from a single chitin-binding domain play in the binding to a chitin substrate. Most of the cysteine residues proved to be critical for binding. AEG12 has a putative secretory signal peptide at the amino-terminus and a putative glycosyl-phosphatidylinositol (GPI) anchor signal at its carboxyl-terminus and the protein was localized by immuno-electron microscopy to the midgut epithelial cell microvilli.
Shao
Li
L
Department of Genetics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, USA.
Devenport
Martin
M
Fujioka
Hisashi
H
Ghosh
Anil
A
Jacobs-Lorena
Marcelo
M
D000330:Aedes / Q000737:chemistry*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002462:Cell Membrane / Q000737:chemistry; D002686:Chitin / Q000737:chemistry; D041981:Gastrointestinal Tract; D005786:Gene Expression Regulation; D015723:Gene Library; D019476:Insect Proteins / Q000096:biosynthesis / Q000737:chemistry*; D007814:Larva; D008969:Molecular Sequence Data; D011485:Protein Binding
D019476:Insect Proteins; D002686:Chitin