Fusome morphogenesis is sufficient to promote female germline stem cell self-renewal in Drosophila

Many tissue-resident stem cells are retained through asymmetric cell division, a process that ensures stem cell self-renewal through each mitotic cell cycle. Asymmetric organelle distribution has been proposed as a mechanism by which stem cells are marked for long-term retention; however, it is not clear whether biased organelle localization is a cause or an effect of asymmetric division. In Drosophila females, an endoplasmic reticulum-like organelle called the fusome is continually regenerated in germline stem cells (GSCs) and associated with GSC division. Here, we report that the β-importin Tnpo-SR is essential for fusome regeneration. Depletion of Tnpo-SR disrupts cytoskeletal organization during interphase and nuclear membrane remodeling during mitosis. Tnpo-SR does not localize to microtubules, centrosomes, or the fusome, suggesting that its role in maintaining these processes is indirect. Despite this, we find that restoring fusome morphogenesis in Tnpo-SR-depleted GSCs is sufficient to rescue GSC maintenance and cell cycle progression. We conclude that Tnpo-SR functionally fusome regeneration to cell cycle progression, supporting the model that asymmetric rebuilding of fusome promotes maintenance of GSC identity and niche retention. Summary Statement Regeneration of the fusome, an ER-like organelle in Drosophila female germline stem cells, relies on Tnpo-SR-dependent reorganization of the microtubule network during interphase.

• Publication year

  2025

• Venue

  bioRxiv

• Publication date

  2025-03-13

• Fields of study

  Biology, Medicine

• Identifiers
  DOI 10.1101/2025.03.10.642432PMID 40161740PMCID 11952372
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar, PubMed

• No claims are published for this paper.

• No concepts are published for this paper.

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