Reprod Nutr Dev January 1, 1981; 21 (1): 135-48.

Germinal vesicle breakdown in the Xenopus laevis oocyte: description of a transient microtubular structure.

Abstract
During progesterone-induced meiotic maturation of Xenopus oocytes in vitro, 7 morphological stages were defined. Using cytological analysis, nuclear breakdown was divided into three stages. Stage 1 corresponded to basal germinal vesicle breakdown. Stage 2 was characterized by the advent and development of a fibrillar network formed by microtubules at the basal part of the nucleus. Below, a lamellar microtubule organizing center (MTOC) was present. Numerous vesicles of smooth endoplasmic reticulum were proximal to both of these structures. During its formation and modification (stages 2 and 3), the fibrillar network migrated towards the animal pole. A prometaphase 1 stage was observed before the formation of the metaphase 1 spindle.

PubMed ID: 7349521
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