Practice question

Early Xenopus blastomeres adhere via maternally supplied EP-cadherin, a calcium-dependent adhesion molecule related to E-cadherin expressed before MBT. EP-cadherin maintains tight association between dividing cells, preventing dissociation and sealing blastocoel cavity through establishment of tight junctions and cortical actin linkage. Adhesion also enables transmission of mechanical forces during epiboly and convergent extension. Without functional EP-cadherin, blastomeres separate, blastocoel leaks, and gastrulation movements fail. After MBT, zygotic cadherins like E-cadherin and C-cadherin replace maternal EP-cadherin for tissue-specific adhesion and morphogenesis during neurulation.