In enucleation protocols for cell biology and nuclear transfer, which reagent is commonly used to disrupt the actin cytoskeleton and facilitate removal of the nucleus?

Introduction / Context:
Enucleation is a key step in somatic cell nuclear transfer and certain cell manipulation procedures. Reagents that disrupt the actin cytoskeleton help separate the nucleus from the rest of the cell for removal under micromanipulation or centrifugation conditions.

Given Data / Assumptions:

• Actin dynamics influence nuclear positioning and membrane mechanics.
• Disrupting actin filaments eases nucleus extrusion or detachment.
• PEG is primarily used to promote cell fusion, not enucleation.

Concept / Approach:
Cytochalasin B binds to actin filaments and inhibits polymerization, weakening cytoskeletal structure. This facilitates enucleation when combined with appropriate physical manipulation (centrifugation or microneedle-assisted removal).

Step-by-Step Solution:

Verification / Alternative check:
Standard nuclear transfer protocols list cytochalasin B as the classic enucleation aid, while PEG is reserved for fusion steps between cells or cytoplasts and karyoplasts.

Why Other Options Are Wrong:

• B/C: PEG promotes fusion, not selective nucleus removal.
• D/E: Ethanol and SDS are nonspecific and damaging, not used for precise enucleation.

Common Pitfalls:
Mixing up enucleation and fusion steps; using excessive cytochalasin concentrations that compromise viability.

Final Answer:
Cytochalasin B