Sequential study of the synaptonemal complex in rat (Rattus norvegicus) oocytes by light and electron microscopy

Abstract

The progression of first meiotic prophase and synaptonemal complex (SC) formation in female rats, Rattus norvegicus S.D., is described through the analysis of the different stages of the first meiotic prophase, and confirms the high synchrony of the process in this species. Leptotene is a stage of very short duration and since pairing of the homologues begins very early, only a leptotene-zygotene stage can be distinguished. The progression of pairing during zygotene is asynchronous. The morphology of the SCs is similar to that described in other species. During diplotene and before disintegration of the lateral elements, desynapsis takes place. In some oocytes a double or even multiple nature of lateral elements was seen. Associations between SCs and nucleoli or nucleolar filaments are frequent. The presence of fragmented SCs can be interpreted as a technical artifact.

Apoptosis in mouse fetal and neonatal oocytes during meiotic prophase one

“…The existence of two waves of pachytene oocytes in B6CBF2 mice is consistent with other data from our group (unpublished) and could be a genetic effect [36,37]. Biphasic observations of prenatal oocyte degeneration and the premeiotic S phase have been reported in rats [30,38]. …”

“…There is considerable discrepancy in the literature concerning the interpretation of microscopic images of meiotic cells as well as the optimal means of cell preparation to obtain ideal cytogenetic spreads. For example, non-intact elements observed microscopically have been interpreted as abnormal, non-viable or degenerating [11,19,24-29] as well as potentially artifactual [30,31]. …”

Influence of p53 and genetic background on prenatal oogenesis and oocyte attrition in mice

“…Later, the pattern of oocytes at pachytene and diplotene become more complex; however, the progression of oocytes during MPI remained significantly different in f1 and f2 mice, influenced by the stage, dpc and genotype as well as between individual mice. Our tentative evidence of an additional wave of MPI in f2 female mice is in agreement with reports in rats (Pujol et al, 1988;Wartenberg et al, 1998). The precise genetic elements responsible for these differences have not been addressed in our study and are worthy of further investigation.…”

The Structure of the Synaptonemal Complexes in Meiocytes of European Domestic Goose (Anser anser)

“…SCs revealed after the application of analogous isolation and chromosome staining techniques was observed in man (SOLARI 1980), Locusta migratoria (COUNCE & MEYER 1973;MACGREGOR & VARLEY 1988), cattle (OEWITOÑSKI & STRANZINGER 1998), Rattus norvegicus (PUJOL et al 1988), Anas platyrhynchos (SOLARI & PIGOZZI 1993), Canis familiaris (LECHNIAK et al 1997), Gallus domesticus (SOLARI 1977) and Sus scrofa (S£OTA 1998).…”