Nuclear cytochemistry of mouse oogenesis: 1. Changes in extranucleolar ribonucleoprotein components through meiotic prophase

The presence of RNP-containing nuclear structures as revealed by ultrastructural cytochemistry has been sequentially followed during mouse oogenesis in ultrathin cryosections. Stage-specific modifications of chromatin, nucleolus, and extranucleolar components are described from the early stages of meiosis to the late prematuration stages. In particular, changes in the population of perichromatin granules are described and confronted with the current information on RNP production during mammalian oogenesis. The cytochemical approach has proved particularly helpful in demonstrating a unique richness in RNP-carrying particles in the nucleus of the growing oocyte, and in the identification of new RNP-carrying components at late stages of oogenesis.