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Nuclear actin has been implicated in regulating cell fate, differentiation, and cellular reprogramming. However, its roles in development and tissue homeostasis remain largely unknown. Here we uncover the role of nuclear actin in regulating stemness usingDrosophilaovarian germline stem cells (GSCs) as a model. We find that the localization and structure of nuclear actin is dynamic in the early germ cells. Nuclear actin recognized by anti-actin C4 is found in both the nucleoplasm and nucleolus of GSCs. The polymeric nucleoplasmic C4 pool is lost after the 2-cell stage, whereas the monomeric nucleolar pool persists to the 8-cell stage, suggesting that polymeric nuclear actin may contribute to stemness. To test this idea, we overexpressed nuclear targeted actin constructs to alter nuclear actin polymerization states in the GSCs and early germ cells. Increasing monomeric nuclear actin, but not polymerizable nuclear actin, causes GSC loss that ultimately results in germline loss. This GSC loss is rescued by simultaneous overexpression of monomeric and polymerizable nuclear actin. Together these data reveal that GSC maintenance requires polymeric nuclear actin. This polymeric nuclear actin likely plays numerous roles in the GSCs, as increasing monomeric nuclear actin disrupts nuclear architecture causing nucleolar hypertrophy, distortion of the nuclear lamina, and heterochromatin reorganization; all factors critical for GSC maintenance and function. These data provide the first evidence that nuclear actin, and in particular, its ability to polymerize, are critical for stem cell function and tissue homeostasisin vivo.
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Dynamic nucleoskeleton in stress
The nucleoskeleton maintains nuclear integrity and chromatin organization at the inner nuclear surface. Here, Wang et al. revealed a disassociation of nuclear skeleton proteins from the nuclear periphery upon heat stress, which affects genome architecture and alters gene expression.
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- Award ID(s):
- 2049931
- PAR ID:
- 10469691
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Nature Plants
- Volume:
- 9
- Issue:
- 7
- ISSN:
- 2055-0278
- Page Range / eLocation ID:
- 1010 to 1011
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1038/s41477-023-01458-1
