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Updated: Jul 6, 2026
06:29
Studying Protein Import into Chloroplasts Using Protoplasts
Published on: December 10, 2018
A protocol for expression of foreign genes in chloroplasts
Dheeraj Verma1, Nalapalli P Samson, Vijay Koya
1Department of Molecular Biology and Microbiology, College of Medicine, University of Central Florida, Biomolecular Science, Building #20, Room 336, Orlando, Florida 32816-2364, USA.
Nature Protocols
|April 5, 2008
Summary
Plant chloroplasts offer a cost-effective bioreactor system for biopharmaceutical production. This technology enables rapid scale-up and oral delivery, bypassing costly purification and sterile injection methods.
Area of Science:
- Biotechnology
- Molecular Biology
- Plant Science
Background:
- Biopharmaceutical and vaccine production face significant costs in traditional fermentation systems.
- Plant chloroplasts present a promising alternative for cost reduction and efficient scale-up.
- Chloroplast transformation technology (CTT) has applications beyond therapeutics, including agronomic traits and biomaterials.
Purpose of the Study:
- To provide a detailed protocol for utilizing plant chloroplasts as bioreactors for therapeutic protein production.
- To demonstrate the efficiency and feasibility of CTT for rapid biopharmaceutical development.
- To highlight the economic and delivery advantages of chloroplast-derived therapeutics.
Main Methods:
- Construction of chloroplast expression and integration vectors.
- Selection and regeneration of transformed plant cells (lettuce and tobacco).
- Evaluation of transgene integration, inheritance, expression, extraction, quantitation, and purification.
Main Results:
- Successful integration of transgenes into chloroplast genomes.
- High levels of functional foreign protein expression achieved within approximately 6 months.
- Demonstrated potential for oral delivery, eliminating the need for extensive purification and sterile injection.
Conclusions:
- Chloroplasts serve as efficient and scalable bioreactors for biopharmaceutical production.
- CTT offers a cost-effective, eco-friendly alternative to traditional methods.
- Maternal inheritance of transgenes in most crop plants enhances biosafety and simplifies containment.
Related Concept Videos
01:18Protein Transport to the Inner Chloroplast Membrane
Proteins targeted to the inner chloroplast membrane, or plastid proteins, are transported by two general pathways: the stop-transfer and the re-insertion or post-import pathways. Most plastid proteins carry N-terminal transit sequences and internal import sequences targeting it to the specific chloroplast subcompartment. Proteins targeted by the stop-transfer pathway have internal hydrophobic sequences that inhibit their translocation into the stroma. As a result, these precursors are arrested...
02:19Export of Mitochondrial and Chloroplast Genes
A eukaryotic cell can have up to three different types of genetic systems: nuclear, mitochondrial, and chloroplast. During evolution, organelles have exported many genes to the nucleus; this transfer is still ongoing in some plant species. Approximately 18% of the Arabidopsis thaliana nuclear genome is thought to be derived from the chloroplast’s cyanobacterial ancestor, and around 75% of the yeast genome derived from the mitochondria’s bacterial ancestor. This export has occurred irrespective...
01:11Protein Transport to the Outer Chloroplast Membrane
Chloroplast outer membrane proteins encoded by the nucleus are synthesized in the cytosol. Soon after synthesis, they bind cytosolic factors such as 14-3-3 protein and the Hsp70 chaperones that keep these precursors in an unfolded state until their translocation.
Two models describe the mechanism of precursor recognition and entry across the outer membrane through the TOC complex. Model 1 suggests the newly synthesized precursor binds to the TOC receptor 159 and forms a complex.
Two models describe the mechanism of precursor recognition and entry across the outer membrane through the TOC complex. Model 1 suggests the newly synthesized precursor binds to the TOC receptor 159 and forms a complex.
01:24Protein Transport to the Stroma
Chloroplasts are triple membrane structures with an outer membrane, an inner membrane, and a thylakoid membrane, each containing distinct metabolite transporters, membrane translocons, and enzymes. Appropriate sorting and translocating these proteins to their correct membrane systems is essential for chloroplast function.
Protein complexes called the translocon of the outer chloroplast membrane or TOC complex, and the translocon of the inner chloroplast membrane or TIC complex mediate the...
Protein complexes called the translocon of the outer chloroplast membrane or TOC complex, and the translocon of the inner chloroplast membrane or TIC complex mediate the...
01:22Protein Transport to the Thylakoids
Thylakoids are membrane-bound sac-like structures within the chloroplast that serve as sites for photosynthesis. Thylakoid lumen contains many electron transport proteins and is enclosed by a thylakoid membrane rich in the light-harvesting complex. Proteins targeted to the thylakoids are transported as precursors and are sorted by the general TOC/TIC import pathway. Once the precursor reaches the stroma, stromal processing peptidases remove their transit signal and expose thylakoid signal...
02:50Transgenic Plants
Recombinant DNA technology called transgenesis is often used to add a foreign gene or remove a detrimental gene from an organism. Such genetically modified organisms are called transgenic organisms.
The first-ever transgenic plant was a tobacco plant developed in 1983 that showed resistance against the tobacco mosaic virus. Since then, many transgenic plants have been developed and commercialized for improving the agricultural, ornamental, and horticultural value of a crop plant. Transgenic...
The first-ever transgenic plant was a tobacco plant developed in 1983 that showed resistance against the tobacco mosaic virus. Since then, many transgenic plants have been developed and commercialized for improving the agricultural, ornamental, and horticultural value of a crop plant. Transgenic...