Comparison of RNA localization during oogenesis within Acipenser ruthenus and Xenopus laevis [Acipenser ruthenus]

In this study we analyzed the spatial and temporal localization of maternal transcripts during oogenesis in Acipenser ruthenus. The occurrence of transcript asymmetry in A. ruthenus has been described at a global level only in matured eggs. However not much is known about the asymmetry during oogenesis. In this study we assessed the temporal establishment of the transcript localization at a global level for A. ruthenus. We were able to determine that there are many transcripts that show temporal variability in the establishment of their localization. We observed an early, predefined and also late pathways for both the vegetally and animally localized transcripts. Additionally, we showed that some maternal transcripts are dynamic during oogenesis with degradation and de novo production being observed. Our study showed that in additional to spatial orientation to the transcripts, there is a strong temporal factor. The discovery of these new temporal profiles should help to better understand the driving forces during embryogenesis. Oocytes from Acipenser ruthenus females were extracted to create two groups: small oocytes (n = 5; size 1320-1500 µm); and big (n = 5, size 1920-2100 µm). Samples were oriented along their animal-vegetal axis and cryosectioned to produce 5 main sections (A (extreme animal) – E (extreme vegetal)). Each section was sequenced and the abundance of the transcript across the section and stages analyzed.