Stages of oocyte development in the zebrafish, Brachydanio rerio

Abstract

Oocyte development has been divided into five stages in the zebrafish Brachydanio rerio, based on morphological criteria and on physiological and biochemical events. In stage I (primary growth stage), oocytes reside in nests with other oocytes (Stage IA) and then within a definitive follicle (Stage IB), where they greatly increase in size. In stage II (cortical alveolus stage), oocytes are distinguished by the appearance of variably sized cortical alveoli and the vitelline envelope becomes prominent. In stage III (vitellogenesis), yolk proteins appear in oocytes and yolk bodies with crystalline yolk accrue during this major growth stage. Ooctes develop the capacity to respond in vitro to the steroid 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) by undergoing oocyte maturation. In stage IV (oocyte maturation), oocytes increase slightly in size, become translucent, and their yolk becomes non-crystalline as they undergo final meiotic maturation in vivo (and in response to DHP in vitro). In stage V (mature egg), eggs (approx. 0.75 mm) are ovulated into the ovarian lumen and are capable of fertilization. This staging series lays the foundation for future studies on the cellular processes occurring during oocyte development in zebrafish and should be useful for experimentation that requires an understanding of stage-specific events. © 1993 Wiley-Liss, Inc.

Particularities of reproduction and oogenesis in teleost fish compared to mammals

“…Oogenesis developmental stages have been extensively described in numerous species, with some differences depending on the species and the classification criteria. Only some of the earlier and the more minutely detailed will be mentioned here: in the flounder, Liopsetta obscura [91,92], goldfish, Carassius auratus [93], several tilapia species [94], Fundulus heteroclitus [95], zebrafish Brachydanio rerio [96], and also reviews by Wallace and Selman [97] and Guraya [98]. Moreover, a recent review skimmed through the present state of knowledge about the mechanisms of oogenesis [99].…”

Previtellogenesis in Antarctic fishes: Comparison with temperate species

“…DISCUSSION Our observations reveal that in the notothenioids the previtellogenetic growth stage does not show unique characteristics. In these species, in fact, the typical morpho-cytological phases described in both tropical and temperate teleosts have been observed (Jones, 1978;Selman et al, 1993). The germ cells in prefollicular stages are gathered in several germinal ridges dispersed throughout the gonad.…”

“…As far as the origin of these bodies is concerned, they apparently do not form from the yolk nucleus since the two structures often coexist. They could represent nucleoli extruded into the cytoplasm (Botte, 1962;Guraya, 1965) or, most likely, 'nuages' such as those previously described in the oocytes of many invertebrates and vertebrates (Beams & Kessel, 1974), including fishes (Norrevang, 1968;Flores & Burns, 1993;Selman et al, 1993). In the Channichthyidae, the 'spherical bodies' resemble the nuages both in size and composition.…”

Transient window of resilience during early development minimizes teratogenic effects of heat in zebrafish embryos

“…1A–E and Kimmel et al, 1995). Mature eggs are arrested at metaphase of meiosis II, which progresses and completes with the extrusion of the second polar body within minutes of the egg coming into contact with water (Selman et al, 1993; Dekens et al, 2003; Nair et al, 2013). If fertilization occurs, egg activation and the initial steps of pronuclear congression and fusion occur concurrently, followed by iterative zygotic mitoses.…”