Towards a novel transgene control switch in insects

McGann, Emily Frances 2019. Towards a novel transgene control switch in insects. MPhil Thesis, Cardiff University. Item availability restricted.

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Abstract

Ligand-inducible transcriptional control devices that regulate ectopic gene expression both temporally and spatially are essential tools for the study of gene function. There are also real-world applications for such systems such as those employed by Oxitec Ltd. for insect pest control, where switch systems are used to control expression of effector proteins. This work presents the first steps towards developing two new small molecule responsive switch systems in insects. The first is the auxin-inducible system taken from plant biology and adapted for use in Drosophila melanogaster. The target protein is tagged with an auxin inducible degron (AID), this is recognised by the plant protein TIR which is expressed ectopically. The interaction between the AID and TIR is mediated by the presence of the phytohormone auxin. When auxin is present TIR binds to AID and recruits the protein degradation machinery of the cell. Thus, silencing expression at the post-translational level. The second utilises the synthetic devices created by Gitzinger et al. (2012) to design a similar system for use in the dengue fever vector Aedes aegypti. The designed system is responsive to vanillic acid and encompasses a trans-activator and an operator sequence. This represents a Van-Off system where vanillic acid is required to silence gene expression. The components for both systems were successfully injected into their respective target organisms and transgenic lines established. Functional assays were conducted to determine the efficacy of the systems. The auxin responsive system as implemented here did not function as predicted however the vanillic acid system did turn on in A. aegypti pupae.

Item Type:	Thesis (MPhil)
Date Type:	Completion
Status:	Unpublished
Schools:	Biosciences
Date of First Compliant Deposit:	11 February 2020
Last Modified:	29 Mar 2021 09:51
URI:	https://orca.cardiff.ac.uk/id/eprint/129493

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