Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 6, 2010
Publication Date: November 1, 2010
Citation: Zhao, L., Becnel, J.J., Clark, G.G., Linthicum, K., Chen, J., Jin, X. 2010. Identification and expression profile of multiple genes in response to magnesium exposure in Culex quinquefasciatus larvae. Journal of Medical Entomology. 47(6):1053-1061. Interpretive Summary: A common salt, magnesium, is important for a transmission of a virus that kills mosquitoes that vector West Nile Virus and other diseases of man and animals. To understand why this salt is essential for virus transmission, USDA, ARS, scientists at the Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, FL, and in Stoneville, MS, used molecular techniques to identify genes that respond to magnesium exposure. Genes that were differentially expressed between a nonmagnesium larval control and magnesium treatment of the mosquito Culex quinquefasciatus larvae were determined. The differentially expressed genes were evaluated and analyzed to determine those that may be important for virus transmission. Magnesium can alter the gene expression in mosquitoes, and understanding this process at the gene level can reveal those necessary for virus transmission and be used to develop novel control strategies.
Technical Abstract: Magnesium is crucial for baculovirus transmission in Culex nigripalpus (Theobald) and Cx. quinquefasciatus (Say) larvae, both in the field and in the laboratory. However, the mechanistic role of magnesium in baculovirus transmission is unknown. To investigate the possible role of a host response factors in baculovirus transmission, suppression subtractive hybridization (SSH) was used to identify target transcripts to magnesium exposure in Cx. quinquefasciatus larvae. SSH was performed in both directions enriching for cDNAs differentially expressed between a nonmagnesium larval control and magnesium (15 mM MgSO4) treatment of Cx. quinquefasciatus larvae held for 1 h at 27 ºC. Clones from differentially expressed genes were evaluated by sequencing and relative gene expression levels were analyzed using quantitative real-time PCR (qPCR). Target transcripts up/down-regulated by magnesium included Cx. quinquefasciatus troponin C, isocitrate dehydrogenase, allergen, cytochrome b5, chymotrypsinogen, apolipophorins, tryptase gamma, tropomyosin invertebrate, carboxylesterase, prolylcarboxypeptidase, and many other hypothetical protein genes. Magnesium can alter the gene expression in a vector mosquito population and understanding this process can provide inside on the mechanistic role of magnesium in baculovirus transmission.