Genetic determinants of Sindbis virus strain TR339 affecting midgut infection in the mosquito Aedes aegypti.
Mosquito midgut epithelial cells (MEC) play a major role in determining whether an arbovirus can successfully infect and be transmitted by mosquitoes. The Sindbis virus (SINV) strain TR339 efficiently infects Aedes aegypti MEC but the SINV strain TE/5'2J poorly infects MEC. SINV determinants for MEC infection have been localized to the E2 glycoprotein. The E2 amino acid sequences of TR339 and TE/5'2J differ at two sites, E2-55 and E2-70. We have altered the TE/5'2J virus genome by site-directed mutagenesis to contain two TR339 residues, E2-55 H-->Q (histidine to glutamine) and E2-70 K-->E (lysine to glutamic acid). We have characterized the growth patterns of derived viruses in cell culture and determined the midgut infection rate (MIR) in A. aegypti mosquitoes. Our results clearly show that the E2-55 H-->Q and the E2-70 K-->E mutations in the TE/5'2J virus increase MIR both independently and in combination. TE/5'2J virus containing both TR339 E2 residues had MIRs similar to the parental TR339 virus. In addition, SINV propagated in a mammalian cell line had a significantly lower A. aegypti midgut 50 % infectious dose than virus propagated in a mosquito cell line.
Pierro
Dennis J
DJ
Arthropod-Borne and Infectious Disease Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA.
Powers
Erik L
EL
Arthropod-Borne and Infectious Disease Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA.
Olson
Ken E
KE
Arthropod-Borne and Infectious Disease Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA.
D000330:Aedes / Q000821:virology*; D000595:Amino Acid Sequence; D000821:Animal Feed; D000818:Animals; D001769:Blood; D004064:Digestive System / Q000821:virology*; D004847:Epithelial Cells / Q000821:virology; D016679:Genome, Viral; D008969:Molecular Sequence Data; D009055:Mouth / Q000821:virology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012845:Sindbis Virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics
D014764:Viral Proteins