In animal cloning protocol, while performing enucleation, which chemical is used for relaxing the cellular cytoskeleton?
In animal cloning protocol, while performing enucleation, which chemical is used for relaxing the cellular cytoskeleton?
Select an option to attempt
Correct Answer: Option B
Explanation
Cytochalasin B in enucleation for somatic cell nuclear transfer:In animal cloning by somatic cell nuclear transfer (SCNT), the recipient oocyte must first be ENUCLEATED (nucleus removed):Procedure:1. Mature metaphase II oocyte is treated with CYTOCHALASIN B.2. Cytochalasin B: a fungal metabolite that disrupts ACTIN FILAMENT polymerisation (binds barbed end of actin filaments, prevents polymerisation).3. This disruption RELAXES the cytoskeleton and cell membrane → makes the oocyte soft and permeable.4. The zona pellucida is pierced with a micropipette → the metaphase chromosomes and spindle complex can be gently aspirated.Alternatively, UV irradiation can be used to destroy the DNA (chemical-free enucleation).Other agents:• Phytohaemagglutinin (PHA): T cell mitogen; not for enucleation.• Colchicine/taxol: microtubule inhibitors, different target.• Pronase: enzyme to remove zona pellucida, not for enucleation per se.Answer: Cytochalasin B disrupts actin filaments, relaxing the oocyte cytoskeleton to allow gentle nucleus removal.