Graduation Term
2020
Degree Name
Master of Science (MS)
Department
School of Biological Sciences
Committee Chair
Nathan Mortimer
Abstract
The female endoparasitoid wasps introduce venom accompanied by an egg into
the larval hosts’ body cavity during oviposition. The venom contains a mixture of
proteins that exploit the host’s biological processes, such as, regulating gene
expression, disrupting immune signaling pathways, or inducing immune cell death to
give a decided advantage to the incipient wasp to develop unchallenged. Drosophila
possesses a highly conserved innate immune response that recognizes and neutralizes
foreign microbes and macroparasites. The venom of Ganaspis hookeri (strain G1)
endoparasitoid wasp has co-evolved to suppresses the humoral phase Drosophila’s
innate immune response by inhibiting Ca2+ bursts needed to induce an immune
response signaling pathway. The intracellular Ca2+ concentration of host plasmatocytes
is altered via a venom specific homolog of the Sarco/endoplasmic reticulum calcium
ATPase (SERCA) as a virulence factor. The venom SERCA (vSERCA) is able to
significantly alter host intracellular Ca2+ homeostasis, disrupting cell signaling. SERCA is
a multipass transmembrane protein, suggesting that vSERCA is likely packaged for
transport through the venom into host plasmatocytes. Extracellular vesicles (EVs), or
venosomes, to transport a variety of venom proteins and peptides. An excellent
question is how vSERCA makes its way from the venom glands of G1 and into host
plasmatocytes to affect Ca+2levels.
Here I will explore how G1 uses venosomes to
package vSERCA and other key virulence factors for transport from the venom gland,
where they are produced, into host hemocytes. I characterize how G1 venom transports
vSERCA and other important virulence factors necessary for regulating host signaling
pathways essential for the Drosophila larval immune response, and the underlying
biogenic mechanisms of venosome directed protein transport. These results are relevant to our understanding of the
evolution of hymenopteran and related species.
Access Type
Thesis-Open Access
Recommended Citation
Lark, Christopher, "Characterizing the Transport of Parasitoid Wasp Genaspis Hookeri Venom Serca into Host Drosophila Hemocytes" (2020). Theses and Dissertations. 1386.
https://ir.library.illinoisstate.edu/etd/1386
DOI
https://doi.org/10.30707/ETD2020.20210719070603179046.58