The Glossina morsitans tsetse fly saliva: General characteristics and identification of novel salivary proteins

• Published in: Insect biochemistry and molecular biology 2007-10, Vol.37 (10), p.1075-1085
• Main Authors: Van Den Abbeele, J., Caljon, G., Dierick, J.-F., Moens, L., De Ridder, K., Coosemans, M.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; amino acid sequences; Animals; complementary DNA; Feeding Behavior; gene expression; gene expression regulation; Glossina morsitans; Glossina morsitans morsitans; hematophagy; Hydrogen-Ion Concentration; insect proteins; Insect Proteins - chemistry; Insect Proteins - isolation & purification; Insect Proteins - metabolism; Molecular Sequence Data; nucleotide sequences; protein content; Saliva; Saliva - chemistry; Saliva - metabolism; Salivary proteins; Salivary Proteins and Peptides - chemistry; Salivary Proteins and Peptides - isolation & purification; Salivary Proteins and Peptides - metabolism; Sequence Alignment; sequence analysis; Sequence Analysis, DNA; Sequence Analysis, Protein; Trypanosoma; Tsetse Flies - metabolism; Tsetse Flies - physiology; Tsetse fly
• ISSN: 0965-1748; 1879-0240
• DOI: 10.1016/j.ibmb.2007.06.006

The tsetse fly ( Glossina spp.) is an obligate blood-sucking insect that transmits different human-pathogenic and livestock threathening trypanosome species in Africa. To obtain more insight in the tsetse salivary function, some general aspects of the tsetse fly saliva and its composition were studied. Direct pH and protein content measurements revealed a moderately alkaline (pH∼8.0) salivary environment with approximately 4.3 μg soluble proteins per gland and a constant representation of the major saliva proteins throughout the blood-feeding cycle. Although major salivary genes are constitutively expressed, upregulation of salivary protein synthesis within 48 h after the blood meal ensures complete protein replenishment from day 3 onwards. Screening of a non-normalised Glossina morsitans morsitans λgt11 salivary gland expression library with serum from a saliva-immunized rabbit identified three full-length cDNAs encoding for novel salivary proteins with yet unknown functions: a 8.3 kDa glycine/glutamate-rich protein ( G. morsitans morsitans salivary gland protein Gmmsgp1), a 12.0 kDa proline-rich protein (Gmmsgp2), and a 97.4 kDa protein composed of a metallophosphoesterase/5′nucleotidase region with a glutamate/aspartate/asparagines-rich region (Gmmsgp3).