Lesson Plan: Gene Editing using CRISPR

Here is a step-by-step guide to using this lesson plan in the classroom/laboratory. We have suggested these steps as a possible plan of action. You may customize the lesson plan according to your preferences and requirements.

Step 1: Topic introduction and discussion

1. Begin with introducing what gene editing is and explain how it is different from genetic engineering- Gene editing, is a process in which DNAis inserted, deleted, modified or replaced at a specific site in the genome of a living organism. Genetic engineering, on the other hand randomly inserts or deletes genetic material to introduce mutations.
2. In gene editing, nucleases/ molecular scissors are used which introduce a double stranded break (DSB) in the DNA at specific locations after which DNA repair mechanisms of the cell take over resulting in targeted mutations (edits).
3. Then, briefly discuss the commonly used nucleases- meganucleases, Zinc Finger Nucleases (ZFNs), transcription activator-like effector-based nucleases (TALENS) and CRISPR- that are used for gene editing.
4. Emphasize that this lesson plan will focus on the CRISPR-Cas9 system of gene editing, as it is reported in recent times to be more efficient and effective than the others.
5. Use this animated video, ‘Genome Editing with CRISPR-Cas9’, narrated by Feng Zhang, McGovern Institute of Brain Research, MIT, to introduce the topic of gene editing using CRISPR-Cas9 system and to briefly describe the structural components of the CRISPR-Cas9 pathway.

Go to the Video

Step 2: Extend understanding of the CRISPR-Cas9 pathway and CRISPR gene editing using an interactive visualization

1. Use the interactive visualization, ‘CRISPR-Cas9 Mechanism & Application’ by Howard Hughes Medical Institute (HHMI) BioInteractive, to enable your students to visualize how the CRISPR-Cas9 technology works at the molecular level and to explore its different components.
2. Start by launching the ‘interactive’ component of the visualization tool.
3. Navigate through the visualization to sequentially describe the gene-editing events of targeting and binding of the CRISPR-Cas9 complex to the target DNA, cleaving or breaking of the DNA at the target location and repairing of the DNA to introduce the desired mutation.
4. Use the ‘explore’ button at every step to describe the different molecular components involved in the pathway.
5. Use the tab, ‘How it’s used’ to view 20 short videos that explain how CRISPR gene editing technology can be used to achieve different results in its applications in science and industry.

Go to the visualization

Step 3: Discuss two case studies where CRISPR gene editing has been used as a climate adaptation strategy

1. Use the video, ‘Gene editing yields tomatoes that flower and ripen weeks earlier’ by Zachary Lippman, Cold Spring Harbor Laboratory (CSHL), to describe his use of CRISPR gene editing in two varieties of tomato plants to make them flower and ripen earlier than usual.
2. Use the video to explain how this approach is useful to obtain faster and higher yields of the tomato crop.
3. Discuss, using the video how this will also enable plants to be grown in higher latitudes, thereby offsetting crop loss, if any, due to global warming.
4. To enable better understanding of Dr Lippman’s work, direct your students to listen to a CSHL Base Pairs podcast, link to which is available in the additional resources section of this lesson plan.
5. Use the reading, ‘CRISPR used to genetically edit coral’ by Hanae Armitage, Office of Communication, Stanford Medicine, to explain the proof-of-principle study published in PNAS by Phillip Cleves et al. (2018).
6. Use this brief communication to explain how this work could allow researchers to use the CRISPR-Cas9 gene editing tool to identify and knock-out the coral genes responsible for coral bleaching due to ocean acidification.
7. Discuss how this technique can thus be useful for coral conservation by building climate-resilient corals.

Go to the Video

Go to the Reading

Suggested questions/assignments for learning evaluation :

1. What is the function of CRISPR in bacteria? Describe the main components of the CRISPR-Cas9 system.
2. Describe the two main DNA repair mechanisms in a cell.
3. Explain how the CRISPR gene editing technique exploits the cell’s DNA repair system to introduce targeted mutations.
4. How can CRISPR gene editing help plant breeding programs to adapt to the effects of climate change? Elaborate using a suitable example.
5. Discuss the use of CRISPR technology as a climate adaptation strategy to conserve coral reefs.

The tools in this lesson plan will enable students to:

1. describe the CRISPR-Cas9 pathway of adaptive immunity in bacteria
2. learn about DNA repair mechanisms in cells
3. understand CRISPR gene editing technique to achieve targeted mutations in cells
4. use of CRISPR gene editing in living organisms as a climate adaptation strategy

If you or your students would like to explore the topic further, these additional resources will be useful.