Axis determination in polyspermic Xenopus laevis eggs

Dev Biol. 1986 Jun;115(2):425-33. doi: 10.1016/0012-1606(86)90262-9.


Polyspermic Xenopus laevis eggs can be identified easily because of regions of pigment accumulation and white stripes, which arise by a nocodazole-sensitive process. Eggs containing up to four sperm are capable of forming a single embryonic axis. Dispermic eggs display two regions of pigment accumulation, one around each sperm entry point (SEP), and one white stripe between the SEPs. Such eggs with a 180 degree separation between the SEPs were bisected before first cleavage along the white stripe, creating dorsal and ventral halves in many cases. Each half cleaved and formed a tadpole. When eggs were bisected early in the period of cytoplasmic reorganization (0.5-0.6 normalized time), each half could form a complete tadpole. When eggs were bisected after the period of reorganization (0.8-0.9), often one half formed a tadpole with a complete head but reduced or absent tail and the other half formed a tadpole with a complete tail but reduced or absent head. These results demonstrate that sperm cooperate to give a single embryonic axis in polyspermic eggs and the development of dorsal and ventral egg halves differs after egg reorganization before first cleavage.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chorionic Gonadotropin / pharmacology
  • Female
  • Fertilization
  • Male
  • Ovulation / drug effects
  • Ovum / cytology
  • Sperm-Ovum Interactions*
  • Spermatozoa / cytology
  • Testis / physiology
  • Xenopus


  • Chorionic Gonadotropin