Date of Award

5-7-2020

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

School of Biological Sciences

First Advisor

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.

Comments

Imported from Lark_ilstu_0092N_11721.pdf

DOI

https://doi.org/10.30707/ETD2020.20210719070603179046.58

Additional Files
Projections of VG.avi (1331 kB)

Page Count

47

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