Final answer:
Gamma-tubulin plays a critical role in the nucleation and assembly of microtubules at the microtubule organizing centers, allowing for chromosome segregation during cell division and dynamic reorganization of the cell's cytoskeleton.
Step-by-step explanation:
The role of γ-tubulin in microtubule nucleation is crucial in the process of microtubule assembly within cells. γ-tubulin complexes are found at the microtubule organizing centers (MTOCs), such as centrosomes in animal cells and their equivalent structures in plant cells. From these organizing centers, γ-tubulin helps initiate the polymerization of α-tubulin and β-tubulin dimers into microtubules. Once nucleation has occurred, the microtubules can elongate by adding more tubulin dimers, predominantly at their plus ends, which play a critical role in cell division by pulling replicated chromosomes to opposite ends of a dividing cell. As a result of their dynamic instability, microtubules can rapidly assemble and disassemble, allowing the cell to rearrange its cytoskeleton in response to different cellular needs.