title: Identification and characterization of the cysteine protease inhibitor gene MdCPI from Musca domestica.
abstract: Cysteine proteinase inhibitors (CPIs) are involved in many vital cellular processes such as signalling pathways, apoptosis, immune response and development; however, no CPIs have yet been reported from the housefly Musca domestica. Here we report the isolation and characterization of a housefly CPI gene designated MdCPI. The gene contains an open reading frame of 357 bp encoding a protein of 118 amino acid residues with a putative signal peptide of 17 amino acid residues. Protein alignment demonstrated a high homology to that of Sarcophaga crassipalpis (identity = 51%). Phylogenetic analysis suggested that all CPIs from dipterans, including the housefly, belong to the I25A family and may be descended from a single common ancestor. The gene was expressed in and purified from Escherichia coli. Biochemical studies showed that MdCPI exerts an inhibiting function on papain, which is a classical assay to confirm CPIs. Real-time quantitative PCR and immunolocalization analysis revealed that MdCPI is specifically expressed in haemocytes and fat bodies. It is highly down-regulated in larvae and markedly up-regulated in the pupal stage, suggesting that it may be related to development.
authors.affiliation: College of Life Sciences, Hebei University, Baoding, Hebei, China.
authors.forename: X
authors.initials: X
authors.lastname: Dong
authors.forename: Fengsong
authors.initials: F
authors.lastname: Liu
authors.forename: D
authors.initials: D
authors.lastname: Zhang
authors.forename: T
authors.initials: T
authors.lastname: Tang
authors.forename: X
authors.initials: X
authors.lastname: Ge
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D015853:Cysteine Proteinase Inhibitors / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D020224:Expressed Sequence Tags; D005216:Fat Body / Q000378:metabolism; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D006434:Hemocytes / Q000378:metabolism; D006793:Houseflies / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007150:Immunohistochemistry; D019476:Insect Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D007814:Larva / Q000378:metabolism; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000378:metabolism; D013211:Staphylococcus aureus
chemical_list: D015853:Cysteine Proteinase Inhibitors; D019476:Insect Proteins; D011994:Recombinant Proteins