Ms Lichelle Grobler
Miss Lichelle Renschie Grobler: FABI 2017
I am currently doing my M.Sc. in Biotechnology at the University of Pretoria in collaboration with the CSIR, with a focus on biopharming in Nicotiana benthamiana. I completed my B.Sc. Biotechnology degree and B.Sc. Honours in Biotechnology at the University of Pretoria at the end of 2015 and 2016 respectively. I recieved both my degrees with Cum Laude (with distinction above 75%) and I aim to maintain a high academic standard throughout my Masters.
In 2013, I opted for a gap year after school to travel and work to earn money and gain life experience. In that time I visited perth, Australia and gain incite into the research industry overseas. During my degree I worked as a laboratory assistant in the Plant Pathology department at the University of Pretoria to gain laboratory experience. Thereafter, I did an internship (mentorship program) in the Plant Science Department in 2015 and in 2016, I was a BOT 161 demonstrator for first year laboratory practicals during my honour studies.
My interests are in the field of plant Biotechnology and Biopharming. I am currently focused on the improvement of plant heterologous protein expression systems to contibute to the pharmaceutical and veterinary industry. In my honours I focused on plant-pathogen interactions and the role of plant hormones in plant defense. Additionally I am interested in crop improvement through biotechnology and development of resistant crop lines.
CRISPR-Cas9 mutagenesis of a selected cysteine protease in Nicotiana benthamiana in order to reduce heterologous protein degradation
This current study is focused in the field of Biotechnology and Biopharming. It is a collaborative project between the University of Pretoria and the CSIR who have leading experts in the field of heterologous protein expression for research and medical purposes. My role in this study is to develop an improved plant heterologous expression system for greater yield of recombinant proteins such as vaccines and antibodies for medical purposes.
Plants are valuable resources that provide us with sustenance and oxygen. In addition, they are also a source of medicines, chemicals, renewable materials and biofuels (Bortesi and Fischer 2015). Not only do plants provide us with so many resources, but they have recently been used as bio-factories to produce a variety of recombinant proteins (RP). These range from research enzymes to edible antibodies and vaccines (Sack et al. 2015). Plant bio-factories are starting to surpassed their predecessors, the microbial and mammalian production platforms, due to its low initial costs; natural encapsulation; absence of human and animal pathogens; and its ability to perform complex post-translational modifications (Merlin et al. 2014). Tobacco varieties have been the most commonly used plants for RP production and remain the strongest contenders for commercial production with the longest history as a successful system for Bio-pharming. Granted, plant bio-factories have their limitations, currently the major bottleneck is low accumulation of RP in plants. Thus far, chloroplast transformation and transient expression has been used to increase yields but RP degradation by proteases is still a major concern (Ahmad et al. 2010).
Recent advances in plant genome editing technologies, have made it possible to easily and efficiently modify plants for optimized recombinant protein production, pathway regulation, post-translational modification and even insertion of whole transgenic pathways (Schaeffer and Nakata 2015). One of the latest technologies, clustered, regularly interspaced, short palindromic repeats (CRISPR)-associated protein (Cas), has revolutionized genome editing in all organisms. This unique system can cleave DNA with single-nucleotide (Nt) accuracy, allowing for the disruption or insertion of genes through non-homologous end joining (NHEJ) and homology-directed repair (HDR) respectively (Belhaj et al. 2013). This technology has opened new doors to genome editing and has made it possible to modify the plant chassie in order to minimize degradation and increase recombinant protein yield.
In this study I aim to mutate a selected protease from N. benthamiana using the latest genome editing CRISPR-Cas9 technology. In addition, I aim to show that with the reduction in selected protease activity, greater yields of a model monomeric recombinant protein is possible.