Ultraestructural changes in the follicular epithelium of Ceratophrys cranwelli previtellogenic oocyte

VILLECCO E.I.; MÓNACO M. E.; SÁNCHEZ S. S.

ZYGOTE

Cambridge University Press

Año: 2007 vol. 15 p. 273 - 283

0967-1994

In this work we carried out ultrastructural, autoradiographic and biochemical analyses of the follicular epithelium during C. cranwelli previtellogenesis. This study revealed that the follicular epithelium in early previtellogenesis is constituted of a single layer of squamous homogeneous cells. During midprevitellogenesis two types of cells develop: dark cells and clear cells. The follicular dark cells are actively involved in the synthesis of RNA, which is transferred to the oocyte through the interface. In late previtellogenesis the dark cells show apoptotic characteristics such as chromatin condensation, DNA fragmentation and cytoplasm shrinkage. This process forms apoptotic bodies that seem to be engulfed by the oocyte. Our results show evidence that, during mid- and late C. cranwelli previtellogenesis, the follicular epithelium undergoes remodelling processes interacting with the oocyte.