Sindbis Virus Entry of Mosquito Midgut Epithelia...Is NRAMP Involved?

Publication Year:
2015
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Repository URL:
https://digitalcommons.unf.edu/etd/614; https://digitalcommons.unf.edu/cgi/viewcontent.cgi?article=1622&context=etd
Author(s):
Chim, Florence Yi Ting; Chim, Florence, 1987-
Tags:
Thesis; University of North Florida; UNF; Dissertations; Academic -- UNF -- Master of Science in Biology; Dissertations; Academic -- UNF -- Biology; Sindbis virus; Alphavirus; Togaviridae; Aedes aegypti; Anopheles quadrimaculatus; NRAMP; Thesis; University of North Florida; UNF; Dissertations; Academic -- UNF -- Master of Science in Biology; Academic -- UNF -- Biology; Sindbis virus; Alphavirus; Togaviridae; Aedes aegypti; Anopheles quadrimaculatus; NRAMP; Biology; Life Sciences
thesis / dissertation description
Sindbis virus (SINV) is an arthropod-borne Alphavirus in the family Togaviridae. Sindbis virus has a broad host range that includes avian, mammalian, and human hosts; therefore, its receptor(s) is/are highly conserved. When the mosquito imbibes a viremic blood meal, the virus infects the midgut cells, disseminates into the hemolymph, and eventually infects the salivary glands. The midgut is an organ of transmission and the virus must overcome the midgut epithelia infection- and escape-barriers. Sindbis virus infection is determined by the chance collision of the glycoproteins with a compatible receptor. Research has supported the involvement of high-affinity laminin receptor and heparan sulfate in SINV binding to host cells. However, it has been suggested that not all strains of SINV are dependent on heparan sulfate for attachment/entry and that SINV could be utilizing multiple receptors. A study using Drosophila demonstrated that, of the nine genes that encode for proteins that enhance SINV infection, only natural resistance-associated macrophage protein (NRAMP) was conserved. A symporter of divalent metals and hydrogen ions, NRAMP is ubiquitously expressed. Overexpression of NRAMP led to an increase in SINV infection of human cells while deletion of NRAMP in mouse and Drosophila decreased SINV infection. Sindbis virus could be utilizing this protein to overcome the infection barriers of mosquito midgut epithelia. In this study, NRAMP was localized to Aedes aegypti and Anopheles quadrimaculatus tissues via immunofluorescence assay and TR339-TaV-eGFP was detected in the midgut epithelia and visceral muscles. We suspect that NRAMP was detected on midguts and/or Malpighian tubules of Aedes aegypti and Anopheles quadrimaculatus. The similarities between the pattern of NRAMP labeling and TR339-TaV-eGFP infection of the midgut suggest that SINV infection is influenced by NRAMP in the midgut epithelia. Because NRAMP is ubiquitously expressed, this research provides insight into the attachment and entry phase of the arbovirus lifecycle.