Regulation of Cell Polarity and RNA Localization in Vertebrate Oocytes - International Review of Cell and Molecular Biology - page 130

Table 4.1 Stages and characteristics of oocytes and eggs in Xenopus and zebrafish
Xenopus
stage

Comparable zebrafish
stage Size ( m m) General features

Previtellogenesis Prestage I 50 Oocytes arrested in diplotene, cystocyte polarity is lost,

mitochondrial aggregates accumulate perinuclearly,
intracellular bridges disconnected

IA: prefollicle
(7-20

<

m m)

Stage I 50-300 Transparent cytoplasm and a conspicuous mitochondrial cloud,

thin follicle cell sheet

IB: follicle phase
(20-140

m)

m

Vitellogenesis Stage II 300-450 Opaque cytoplasm, mitochondrial cloud breakdown,

formation of vitelline membrane, cortical granules begin to
form, microvilli develop in follicle cells and theca and follicle
cell layers thicken

II: cortical alveolus
(140-340 m)

m

Stage III 450-600 Oocyte becomes vascularized, melanin production initiates,

maximum extent of lampbrush chromosomes, uniform yolk

III: vitellogenesis
(340-690 m m)

Stage IV 600-1000 Animal-vegetal distinction develops, vitellogenesis is most
rapid, gradient of yolk platelets forms, GV migrates animally

Stage V 1000-1200 A distinct AV pigment border forms, the GV is at the animal

pole, endocytosis is reduced

IV: maturation
(690-730

m)

m

Postvitellogenesis Stage VI 1200 Unpigmented equatorial band forms, microvilli and nucleoli are

reduced, cortical granules aligned in the cortex

>

Postoocyte
maturation

Egg 1200 Metaphase II arrest, spindle at the animal pole, absence of

secretion and post- trans -Golgi trafficking

V: egg (730-750 m)

> m

After Dumont (1972) and Selman et al. (1993) .