The stem cell-intrinsic model of self-renewal via asymmetric cell division (ACD) posits that fate determinants be partitioned unequally between daughter cells to either activate or suppress the stemness state. ACD is a purported mechanism by which hematopoietic stem cells (HSCs) self-renew, but definitive evidence for this cellular process remains open to conjecture. To address this issue, we chose 73 candidate genes that function within the cell polarity network to identify potential determinants that may concomitantly alter HSC fate while also exhibiting asymmetric segregation at cell division. Initial gene-expression profiles of polarity candidates showed high and differential expression in both HSCs and leukemia stem cells. Altered HSC fate was assessed by our established in vitro to in vivo screen on a subcohort of candidate polarity genes, which revealed 6 novel positive regulators of HSC function: Ap2a2, Gpsm2, Tmod1, Kif3a, Racgap1, and Ccnb1. Interestingly, live-cell videomicroscopy of the endocytic protein AP2A2 shows instances of asymmetric segregation during HSC/progenitor cell cytokinesis. These results contribute further evidence that ACD is functional in HSC self-renewal, suggest a role for Ap2a2 in HSC activity, and provide a unique opportunity to prospectively analyze progeny from HSC asymmetric divisions.
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http://dx.doi.org/10.1182/blood-2011-11-393272 | DOI Listing |
Int J Mol Sci
January 2025
Department of Life Sciences, Ben Gurion University of the Negev, Beer-Sheva 8410501, Israel.
Phenotypic variability in isogenic bacterial populations is a remarkable feature that helps them cope with external stresses, yet it is incompletely understood. This variability can stem from gene expression noise and/or the unequal partitioning of low-copy-number freely diffusing proteins during cell division. Some high-copy-number components are transiently associated with almost immobile large assemblies (hyperstructures) and may be unequally distributed, contributing to bacterial phenotypic variability.
View Article and Find Full Text PDFNat Commun
January 2025
Laboratory of Epigenome Integrity, Epigenetics & Cell Fate Centre, UMR7216 CNRS, Université Paris Cité, Paris, France.
The faithful segregation of intact genetic material and the perpetuation of chromatin states through mitotic cell divisions are pivotal for maintaining cell function and identity across cell generations. However, most exogenous mutagens generate long-lasting DNA lesions that are segregated during mitosis. How this segregation is controlled is unknown.
View Article and Find Full Text PDFEMBO J
January 2025
Cell Biology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK.
Elongator is a tRNA-modifying complex that regulates protein translation. Recently, a moonlighting function of Elongator has been identified in regulating the polarization of the microtubule cytoskeleton during asymmetric cell division. Elongator induces symmetry breaking of the anaphase midzone by selectively stabilizing microtubules on one side of the spindle, contributing to the downstream polarized segregation of cell-fate determinants, and therefore to cell fate determination.
View Article and Find Full Text PDFPLoS One
December 2024
School of Medicine and Health Sciences, Center for Research in Genetics and Genomics (CIGGUR), Institute of Translational Medicine (IMT), Universidad del Rosario, Bogotá D.C., Colombia.
Hereditary angioedema type 1 (HAE1) is a rare, genetically heterogeneous, and autosomal dominant disease. It is a highly variable, insidious, and potentially life-threatening condition, characterized by sudden local, often asymmetric, and episodic subcutaneous and submucosal swelling, caused by pathogenic molecular variants in the SERPING1 gene, which codes for C1-Inhibitor protein. This study performed the phenotypic and molecular characterization of a HAE1 cluster that includes the largest number of affected worldwide.
View Article and Find Full Text PDFbioRxiv
December 2024
Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
Spindles are essential for accurate chromosome segregation in all eukaryotic cells. This study presents a novel approach for isolating fresh mammalian spindles from mouse oocytes, establishing it as a valuable model system for a wide range of possible studies. Our method enables the investigation of the physical properties and migration force of meiotic spindles in oocytes.
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