Practice question

Cortical rotation in frog eggs involves coordinated movement of outer cortical cytoplasm relative to inner endoplasm. After fertilization-induced calcium wave, subcortical microtubules polymerize parallel to future dorsal-ventral axis and kinesin motors transport cortex containing membrane-anchored Dishevelled, Wnt11 mRNA, and GBP about thirty degrees toward side opposite sperm entry. Central yolk cytoplasm remains stationary, creating shear zone. This repositioning brings beta-catenin stabilizing factors dorsally where GSK-three inhibition occurs, allowing nuclear accumulation and formation of gray crescent. Entire egg does not rotate.