The effects of midgut serine proteases on dengue virus type 2 infectivity of Aedes aegypti.
Dengue viruses (DENV) cause significant morbidity and mortality worldwide and are transmitted by the mosquito Aedes aegypti. Mosquitoes become infected after ingesting a viremic bloodmeal, and molecular mechanisms involved in bloodmeal digestion may affect the ability of DENV to infect the midgut. We used RNA interference (RNAi) to silence expression of four midgut serine proteases and assessed the effect of each RNAi phenotype on DENV-2 infectivity of Aedes aegypti. Silencing resulted in significant reductions in protease mRNA levels and correlated with a reduction in activity except in the case of late trypsin. RNA silencing of chymotrypsin, early and late trypsin had no effect on DENV-2 infectivity. However, silencing of 5G1 or the addition of soybean trypsin inhibitor to the infectious bloodmeals significantly increased midgut infection rates. These results suggest that some midgut serine proteases may actually limit DENV-2 infectivity of Ae. aegypti.
Brackney
Doug E
DE
Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, USA. dbrackney@salud.unm.edu
Foy
Brian D
BD
Olson
Ken E
KE
D000330:Aedes / Q000201:enzymology* / Q000821:virology*; D000818:Animals; D003716:Dengue Virus / Q000145:classification / Q000472:pathogenicity*; D005260:Female; D041981:Gastrointestinal Tract / Q000201:enzymology; D020868:Gene Silencing; D007303:Insect Vectors / Q000201:enzymology* / Q000821:virology*; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology
D012333:RNA, Messenger; D015842:Serine Proteinase Inhibitors; D012697:Serine Endopeptidases