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Kong R, Li J, Liu F, Ma Y, Zhao H, Zhao H, Ma M, Li Z. A feedforward loop between JAK/STAT downstream target p115 and STAT in germline stem cells. Stem Cell Reports 2023; 18:1940-1953. [PMID: 37683644 PMCID: PMC10656303 DOI: 10.1016/j.stemcr.2023.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 08/10/2023] [Accepted: 08/11/2023] [Indexed: 09/10/2023] Open
Abstract
The maintenance of germline stem cells (GSCs) is essential for tissue homeostasis. JAK/STAT signaling maintains GSC fate in Drosophila testis. However, how JAK/STAT signaling maintains male GSC fate through its downstream targets remains poorly understood. Here, we identify p115, a tER/cis-Golgi golgin protein, as a putative downstream target of JAK/STAT signaling. p115 maintains GSC fate independent of GM130 and GRASP65. p115 localizes in cytosol, the ER and Golgi apparatus in germline cells and is required for the morphology of the ER and Golgi apparatus. Furthermore, depletion of p115 in GSCs results in aberrant spindle orientation. Mechanistically, p115 associates with and stabilizes STAT. Finally, ectopic expression of STAT completely restores GSC loss caused by p115 depletion. Collectively, JAK/STAT signaling and p115 form a feedforward loop to maintain male GSC fate. Our work provides new insights into the regulatory mechanism of how stem cell maintenance is properly controlled by JAK/STAT signaling.
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Affiliation(s)
- Ruiyan Kong
- College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Juan Li
- College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Fuli Liu
- College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Yankun Ma
- College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Hang Zhao
- College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Hanfei Zhao
- College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Meifang Ma
- College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Zhouhua Li
- College of Life Sciences, Capital Normal University, Beijing 100048, China.
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Rocha JJ, Jayaram SA, Stevens TJ, Muschalik N, Shah RD, Emran S, Robles C, Freeman M, Munro S. Functional unknomics: Systematic screening of conserved genes of unknown function. PLoS Biol 2023; 21:e3002222. [PMID: 37552676 PMCID: PMC10409296 DOI: 10.1371/journal.pbio.3002222] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 06/27/2023] [Indexed: 08/10/2023] Open
Abstract
The human genome encodes approximately 20,000 proteins, many still uncharacterised. It has become clear that scientific research tends to focus on well-studied proteins, leading to a concern that poorly understood genes are unjustifiably neglected. To address this, we have developed a publicly available and customisable "Unknome database" that ranks proteins based on how little is known about them. We applied RNA interference (RNAi) in Drosophila to 260 unknown genes that are conserved between flies and humans. Knockdown of some genes resulted in loss of viability, and functional screening of the rest revealed hits for fertility, development, locomotion, protein quality control, and resilience to stress. CRISPR/Cas9 gene disruption validated a component of Notch signalling and 2 genes contributing to male fertility. Our work illustrates the importance of poorly understood genes, provides a resource to accelerate future research, and highlights a need to support database curation to ensure that misannotation does not erode our awareness of our own ignorance.
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Affiliation(s)
- João J. Rocha
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | | | - Tim J. Stevens
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | | | - Rajen D. Shah
- Centre for Mathematical Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Sahar Emran
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Cristina Robles
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Matthew Freeman
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Sean Munro
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
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Wu S, Yang Y, Tang R, Zhang S, Qin P, Lin R, Rafel N, Lucchetta EM, Ohlstein B, Guo Z. Apical-basal polarity precisely determines intestinal stem cell number by regulating Prospero threshold. Cell Rep 2023; 42:112093. [PMID: 36773292 DOI: 10.1016/j.celrep.2023.112093] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 12/05/2022] [Accepted: 01/25/2023] [Indexed: 02/12/2023] Open
Abstract
Apical-basal polarity and cell-fate determinants are crucial for the cell fate and control of stem cell numbers. However, their interplay leading to a precise stem cell number remains unclear. Drosophila pupal intestinal stem cells (pISCs) asymmetrically divide, generating one apical ISC progenitor and one basal Prospero (Pros)+ enteroendocrine mother cell (EMC), followed by symmetric divisions of each daughter before adulthood, providing an ideal system to investigate the outcomes of polarity loss. Using lineage tracing and ex vivo live imaging, we identify an interlocked polarity regulation network precisely determining ISC number: Bazooka inhibits Pros accumulation by activating Notch signaling to maintain stem cell fate in pISC apical daughters. A threshold of Pros promotes differentiation to EMCs and avoids ISC-like cell fate, and over-threshold of Pros inhibits miranda expression to ensure symmetric divisions in pISC basal daughters. Our work suggests that a polarity-dependent threshold of a differentiation factor precisely controls stem cell number.
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Affiliation(s)
- Song Wu
- Department of Medical Genetics, School of Basic Medicine, Institute for Brain Research, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Yang Yang
- Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Ruizhi Tang
- Department of Medical Genetics, School of Basic Medicine, Institute for Brain Research, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Song Zhang
- Department of Medical Genetics, School of Basic Medicine, Institute for Brain Research, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Peizhong Qin
- Department of Medical Genetics, School of Basic Medicine, Institute for Brain Research, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Rong Lin
- Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Neus Rafel
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA
| | - Elena M Lucchetta
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA
| | - Benjamin Ohlstein
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA
| | - Zheng Guo
- Department of Medical Genetics, School of Basic Medicine, Institute for Brain Research, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China.
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Saraste J, Prydz K. A New Look at the Functional Organization of the Golgi Ribbon. Front Cell Dev Biol 2019; 7:171. [PMID: 31497600 PMCID: PMC6713163 DOI: 10.3389/fcell.2019.00171] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 08/07/2019] [Indexed: 12/14/2022] Open
Abstract
A characteristic feature of vertebrate cells is a Golgi ribbon consisting of multiple cisternal stacks connected into a single-copy organelle next to the centrosome. Despite numerous studies, the mechanisms that link the stacks together and the functional significance of ribbon formation remain poorly understood. Nevertheless, these questions are of considerable interest, since there is increasing evidence that Golgi fragmentation – the unlinking of the stacks in the ribbon – is intimately connected not only to normal physiological processes, such as cell division and migration, but also to pathological states, including neurodegeneration and cancer. Challenging a commonly held view that ribbon architecture involves the formation of homotypic tubular bridges between the Golgi stacks, we present an alternative model, based on direct interaction between the biosynthetic (pre-Golgi) and endocytic (post-Golgi) membrane networks and their connection with the centrosome. We propose that the central domains of these permanent pre- and post-Golgi networks function together in the biogenesis and maintenance of the more transient Golgi stacks, and thereby establish “linker compartments” that dynamically join the stacks together. This model provides insight into the reversible fragmentation of the Golgi ribbon that takes place in dividing and migrating cells and its regulation along a cell surface – Golgi – centrosome axis. Moreover, it helps to understand transport pathways that either traverse or bypass the Golgi stacks and the positioning of the Golgi apparatus in differentiated neuronal, epithelial, and muscle cells.
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Affiliation(s)
- Jaakko Saraste
- Department of Biomedicine and Molecular Imaging Center, University of Bergen, Bergen, Norway
| | - Kristian Prydz
- Department of Biosciences, University of Oslo, Oslo, Norway
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