Quantitative analysis of La Crosse virus transcription and replication in cell cultures and mosquitoes.
La Crosse (LAC) virus (family Bunyaviridae, genus Orthobunyavirus) small (S) segment negative-sense RNA genome (vRNA), positive-sense full-length RNA complement (vcRNA), and subgenomic mRNA were assayed in infected cell cultures and female Aedes (Ochlerotatus) triseriatus mosquito tissues using quantitative PCR (Q-PCR). During persistent infection of C6/36 (Aedes albopictus) and MAT (Aedes triseriatus) cultured cells and cytolytic infection of BHK-21 cultured cells, LAC vRNA was the most abundant RNA species, followed by mRNA and vcRNA. RNA copy numbers per cell were quantified and vRNA correlated to virus titer in cell culture medium. The Q-PCR assay proved more sensitive than reverse transcription (RT)-PCR and immunofluorescence assays (IFA) for detecting LAC virus infection of mosquitoes. After infection of female mosquitoes orally, quantities of LAC RNA increased in ovaries for 6 days, and as ovarian biosynthetic activity quiesced, LAC RNA quantities decreased then remained detectable at a low level. After a second, noninfectious blood meal, quantities of LAC RNA in ovaries increased significantly, quantitatively confirming correlation of LAC virus RNA synthesis with vector metabolic activity. Coregulation of viral replication and mosquito ovary metabolic activity may condition efficient transovarial transmission.
Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, USA.
Brian J
BJ
Kempf
Carol D
CD
Blair
Barry J
BJ
Beaty
D000330:Aedes / Q000821:virology; D000818:Animals; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D006224:Cricetinae; D017931:DNA Primers; D004670:Encephalitis, California / Q000821:virology*; D019085:Fluorescent Antibody Technique, Direct; D015967:Gene Expression Regulation, Viral; D006801:Humans; D018062:La Crosse virus / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D012367:RNA, Viral / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic; D014709:Vero Cells; D014779:Virus Replication
D017931:DNA Primers; D012367:RNA, Viral