Fill in the blanks:
Spindle fibre is made up of `"________"` protein.

Explanation

**Step-by-Step Solution:**

1. **Understanding Spindle Fibers**: Spindle fibers are structures that play a crucial role during cell division, specifically during mitosis and meiosis. They help in the movement of chromosomes.

2. **Composition of Spindle Fibers**: Spindle fibers are primarily composed of proteins. The specific type of protein that makes up these fibers is essential for their function.

3. **Identifying the Protein**: The video transcript mentions that spindle fibers are made up of "microtubules." Microtubules are a component of the cytoskeleton and are crucial for various cellular processes, including the formation of spindle fibers.

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