SSBD - ssbd-repos-000464

Description

Oocyte formation in mammals is a tightly regulated process critical for female fertility. We developed an ex vivo culture system that mimics in vivo ovarian development and enables long-term, high-resolution live imaging of mouse fetal ovaries. This dataset comprises time-lapse image sequences capturing dynamic germ cell behaviors during the transition from oogonia to nascent oocytes.

Submited Date

2025-08-14

Release Date

2026-04-21

Funding information

File formats

The dataset contains image files in CZI, LSM, TIFF, and JPEG formats. CZI and LSM are Zeiss microscope file formats that store multi-dimensional imaging data. TIFF and JPEG files are standard formats; TIFF images are uncompressed or losslessly compressed, whereas JPEG images are lossy compressed. Movie files are provided in AVI or MP4 formats, both using standard compression codecs.

Organism

Mus musculus

GO Molecular Function (MF)

GO Biological Process (BP)

GO Cellular Component (CC)

Method Summary

See details in Aizawa, et. al. (2025) bioRxiv.

Related paper(s)

Aizawa, Eishi, Shimamoto, So, Kajikawa, Eriko, Hara, Junko, Abe, Takaya, Shibuya, Hiroki, Kitajima, Tomoya S. (2026) Dynamic blebbing and absence of organelle transfer during mouse oocyte formation, The EMBO Journal

Published in April 21, 2026

doi: 10.1038/s44318-026-00780-6

(Abstract) Oocyte formation in mammals is a tightly regulated process essential for female fertility, yet the underlying mechanisms remain poorly understood. In this study, we establish an ex vivo culture system that faithfully recapitulates in vivo development and enables long-term live imaging of mouse fetal ovaries. Using high resolution imaging, we capture the dynamic behaviors of germ cells during the development from oogonia to nascent oocytes. We identify pronounced blebbing activity during the mitosis-to-meiosis transition. This behavior is regulated by meiotic initiation signals, underscoring its potential developmental relevance, although its precise role remains unclear. A prevailing model suggests that oocyte formation involves organelle transfer from neighboring germ cells during cyst breakdown. However, through photoconversion-based tracking, we observe no detectable transfer of mitochondria or centrosomes, as organelles remain confined to individual cells. These findings point to alternative mechanisms for cytoplasmic enrichment in oocytes. Our study provides new insights into mammalian oocyte formation and establishes a powerful platform for analyzing germ cell dynamics in real time.

SSBD:repository

Summary of ssbd-repos-000464