Various bacterial species have developed immune systems against viruses. One immune system is called CRISPR/Cas. The bacterium uses CRISPR/Cas to cut the DNA of viruses that enter the bacterium. Zhang et al. (2018) (https://doi.org/10.1111/pbi.12881) have placed such a CRISPR/Cas system, originating from a bacterium, in a plant, aiming at making plants resistant to viruses. The bacterial immune system is, as it were, transplanted to the plant.
Read the abstract of this article carefully.
Also read the Introduction.
Read the first paragraph of Results
Study Figure 1A (Page 1417) and then answer the following questions:
1. What is the purpose of this research?
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c. How is the specificity of the CRISPR/Cas9 system achieved, which makes it work against specific viruses, but not against other viruses? Does it also cut in plant RNA?
Results. Figure 1.
6. Figure 1A shows the structure of the T-DNA that the researchers have built and put into a vector. They brought that vector into the bacterium Agrobacterium tumefaciens, and then A. tumefaciens introduced the piece of DNA between the left border (LB) and right border (RB) into the plant. The piece of DNA between these two borders is called T-DNA (transfer DNA).
Search for which parts. Identify all components of the T-DNA in Figure 1A, and give the function for each component.
To get started: LB = left border, this is the left border of the T-DNA in A. tumefaciens.
Even more help: NOS and Ter are 'terminators'. What is the function of a terminator?
7. From which bacteria is the Cas gene used here? Why was this bacterium chosen, and not a much more common bacterium, such as Streptococcus?
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