Improved recombinant protein production in Arabidopsis thaliana

Trends and Applications of Omics Technologies to Functional Characterisation of Enzymes and Protein Metabolites Produced by Fungi

Identifying and adopting industrial applications for proteins and enzymes derived from fungi strains have been at the focal point of several studies in recent times. To facilitate such studies, it is necessary that advancements and innovation in mycological and molecular characterisation are concomitant. This review aims to provide a detailed overview of the necessary steps employed in both qualitative and quantitative research using the omics technologies that are pertinent to fungi characterisation. This stems from the understanding that data provided from the functional characterisation of fungi and their metabolites is important towards the techno-economic feasibility of large-scale production of biological products. The review further describes how the functional gaps left by genomics, internal transcribe spacer (ITS) regions are addressed by transcriptomics and the various techniques and platforms utilised, including quantitive reverse transcription polymerase chain reaction (RT-qPCR), hybridisation techniques, and RNA-seq, and the insights such data provide on the effect of environmental changes on fungal enzyme production from an expressional standpoint. The review also offers information on the many available bioinformatics tools of analysis necessary for the analysis of the overwhelming data synonymous with the omics approach to fungal characterisation.

Plant Platforms for Efficient Heterologous Protein Production

Production of recombinant proteins is primarily established in cultures of mammalian, insect and bacterial cells. Concurrently, concept of using plants to produce high-value pharmaceuticals such as vaccines, antibodies, and dietary proteins have received worldwide attention. Newer technologies for plant transformation such as plastid engineering, agroinfiltration, magnifection, and deconstructed viral vectors have been used to enhance the protein production in plants along with the inherent advantage of speed, scale, and cost of production in plant systems. Production of therapeutic proteins in plants has now a more pragmatic approach when several plant-produced vaccines and antibodies successfully completed Phase I clinical trials in humans and were further scheduled for regulatory approvals to manufacture clinical grade products on a large scale which are safe, efficacious, and meet the quality standards. The main thrust of this review is to summarize the data accumulated over the last two decades and recent development and achievements of the plant derived therapeutics. It also attempts to discuss different strategies employed to increase the production so as to make plants more competitive with the established production systems in this industry.

Efficient Plant Production of Recombinant NS1 Protein for Diagnosis of Dengue

Dengue fever is endemic in more than 120 countries, which account for 3.9 billion people at risk of infection worldwide. The absence of a vaccine with effective protection against the four serotypes of this virus makes differential molecular diagnosis the key step for the correct treatment of the disease. Rapid and efficient diagnosis prevents progression to a more severe stage of this disease. Currently, the limiting factor in the manufacture of dengue (DENV) diagnostic kits is the lack of large-scale production of the non-structural 1 (NS1) protein (antigen) to be used in the capture of antibodies from the blood serum of infected patients. In this work, we use plant biotechnology and genetic engineering as tools for the study of protein production for research and commercial purposes. Gene transfer, integration and expression in plants is a valid strategy for obtaining large-scale and low-cost heterologous protein production. The authors produced NS1 protein of the dengue virus serotype 2 (NS1DENV2) in the Arabidopsis thaliana plant. Transgenic plants obtained by genetic transformation expressed the recombinant protein that was purified and characterized for diagnostic use. The yield was 203 μg of the recombinant protein per gram of fresh leaf. By in situ immunolocalization, transgenic protein was observed within the plant tissue, located in aggregates bodies. These antigens showed high sensitivity and specificity to both IgM (84.29% and 91.43%, respectively) and IgG (83.08% and 87.69%, respectively). The study goes a step further to validate the use of plants as a strategy for obtaining large-scale and efficient protein production to be used in dengue virus diagnostic tests.

Partial purification and immunodetection of cell surface glycoproteins from plants

Cell surface glycoproteins in plants were first described more than 50 years ago, and yet, the precise mechanisms by which they operate remain elusive to this day. Studying glycoproteins is often challenging due to their subcellular localization (many secreted or membrane associated) and the extent of glycosylation present on the protein backbone, which can have profound effects on protein structure and behavior. In plants, additional layers of complexity exist as cell surface glycoproteins are in close contact, and in some cases, establish direct linkages with the polysaccharide networks present in the cell wall. In this chapter, we guide the reader through a protocol aimed to address the glycosylation status of a presumed cell surface glycoprotein. First, we discuss the advantages and disadvantages of using plants as homologous expression systems for recombinant glycoprotein production. Next, we describe a protocol for microsomal enrichment, followed by partial purification by affinity chromatography and finally glycodetection by immunoblotting using monoclonal antibodies targeting cell wall glycans. We particularly focus on the hydroxyproline-rich glycoprotein (HRGP) family, the most abundant family of glycoproteins in the plant cell wall. We provide examples of two putative HRGP chimeric proteins, one akin to extensins and the second an arabinogalactan protein (AGP)-like protein. For the latter, we provide an AGP-specific protocol to ensure enrichment of members of this group, which can be used independently or in conjunction with the described protocol. Throughout the chapter, we provide recommendations for the handling of plant glycoproteins and highlight special considerations for experimental design, along with troubleshooting suggestions.

Arabidopsis Hairy Roots Producing High Level of Active Human Gastric Lipase

Arabidopsis hairy roots were used to produce human gastric lipase. When treated with 2,4-D, the hairy roots developed into thick organs that produced more protein than untreated roots. This was first assessed using green fluorescent protein-producing root lines from which the protein diffused into the culture medium. When growing hairy roots which express the human gastric lipase gene, very little lipase was found in the medium. Incubating the roots in a low pH buffer resulted in lipase diffusion into the buffer, avoiding the need for grinding. The activity of the enzyme on 4-methylumbellireryl-oleate and on tributyrin was determined. Approximately 6000 units of enzyme were recovered per gram of root. The enzyme was also extracted from freeze-dried roots before and after a 2-month storage period at room temperature. This work demonstrates the relevance of Arabidopsis hairy roots for the production of human gastric lipase.