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Hub T, Cornean A, Round K, Fleming T, Freichel M, Medert R. Streamlined Generation of CRISPR/Cas9-Mediated Single-Cell Knockout Clones in Murine Cell Lines. ACS Pharmacol Transl Sci 2024; 7:1291-1301. [PMID: 38751646 PMCID: PMC11091971 DOI: 10.1021/acsptsci.3c00338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 04/02/2024] [Accepted: 04/04/2024] [Indexed: 05/18/2024]
Abstract
Clonal cell lines harboring loss-of-function mutations in genes of interest are crucial for studying the cellular functions of the encoded proteins. Recent advances in genome engineering have converged on the CRISPR/Cas9 technology to quickly and reliably generate frameshift mutations in the target genes across various cell lines and species. Although high on-target cleavage efficiencies can be obtained reproducibly, screening and identifying clones with loss-of-function alleles remains a major bottleneck. Here, we describe a single sgRNA strategy to generate CRISPR/Cas9-mediated frameshift mutations in target genes of mammalian cell lines that can be easily and cost-effectively identified. Given the proliferation of workhorse cell lines such as N2a cells and the resulting clonal expansion of the cell type, our protocol can facilitate the isolation of knockout clonal cell lines and their genetic validation within a period of down to 6-8 weeks.
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Affiliation(s)
- Tobias Hub
- Institute
of Pharmacology, Heidelberg University, Heidelberg 69120, Germany
| | - Alex Cornean
- Institute
of Pharmacology, Heidelberg University, Heidelberg 69120, Germany
- Partner
Site Heidelberg/Mannheim, DZHK (German Centre
for Cardiovascular Research), Heidelberg, Germany
| | - Kellen Round
- Institute
of Pharmacology, Heidelberg University, Heidelberg 69120, Germany
| | - Thomas Fleming
- Department
of Internal Medicine I and Clinical Chemistry, University Hospital Heidelberg, Heidelberg 69120, Germany
- German
Center for Diabetes Research (DZD), Neuherberg 85764, Germany
| | - Marc Freichel
- Institute
of Pharmacology, Heidelberg University, Heidelberg 69120, Germany
- Partner
Site Heidelberg/Mannheim, DZHK (German Centre
for Cardiovascular Research), Heidelberg, Germany
| | - Rebekka Medert
- Institute
of Pharmacology, Heidelberg University, Heidelberg 69120, Germany
- Partner
Site Heidelberg/Mannheim, DZHK (German Centre
for Cardiovascular Research), Heidelberg, Germany
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Mukhopadhyay AG, Toropova K, Daly L, Wells JN, Vuolo L, Mladenov M, Seda M, Jenkins D, Stephens DJ, Roberts AJ. Structure and tethering mechanism of dynein-2 intermediate chains in intraflagellar transport. EMBO J 2024; 43:1257-1272. [PMID: 38454149 PMCID: PMC10987677 DOI: 10.1038/s44318-024-00060-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 02/06/2024] [Accepted: 02/09/2024] [Indexed: 03/09/2024] Open
Abstract
Dynein-2 is a large multiprotein complex that powers retrograde intraflagellar transport (IFT) of cargoes within cilia/flagella, but the molecular mechanism underlying this function is still emerging. Distinctively, dynein-2 contains two identical force-generating heavy chains that interact with two different intermediate chains (WDR34 and WDR60). Here, we dissect regulation of dynein-2 function by WDR34 and WDR60 using an integrative approach including cryo-electron microscopy and CRISPR/Cas9-enabled cell biology. A 3.9 Å resolution structure shows how WDR34 and WDR60 use surprisingly different interactions to engage equivalent sites of the two heavy chains. We show that cilia can assemble in the absence of either WDR34 or WDR60 individually, but not both subunits. Dynein-2-dependent distribution of cargoes depends more strongly on WDR60, because the unique N-terminal extension of WDR60 facilitates dynein-2 targeting to cilia. Strikingly, this N-terminal extension can be transplanted onto WDR34 and retain function, suggesting it acts as a flexible tether to the IFT "trains" that assemble at the ciliary base. We discuss how use of unstructured tethers represents an emerging theme in IFT train interactions.
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Affiliation(s)
- Aakash G Mukhopadhyay
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK
| | - Katerina Toropova
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK
| | - Lydia Daly
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK
- Randall Centre of Cell & Molecular Biophysics, King's College London, London, UK
| | - Jennifer N Wells
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK
- MRC London Institute of Medical Sciences (LMS), London, UK
| | - Laura Vuolo
- Cell Biology Laboratories, School of Biochemistry, University of Bristol, Bristol, UK
| | - Miroslav Mladenov
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK
- Cellular Signalling and Cytoskeletal Function Laboratory, The Francis Crick Institute, London, UK
| | - Marian Seda
- UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Dagan Jenkins
- UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - David J Stephens
- Cell Biology Laboratories, School of Biochemistry, University of Bristol, Bristol, UK
| | - Anthony J Roberts
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK.
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Freke GM, Martins T, Davies RJ, Beyer T, Seda M, Peskett E, Haq N, Prasai A, Otto G, Jeyabalan Srikaran J, Hernandez V, Diwan GD, Russell RB, Ueffing M, Huranova M, Boldt K, Beales PL, Jenkins D. De-Suppression of Mesenchymal Cell Identities and Variable Phenotypic Outcomes Associated with Knockout of Bbs1. Cells 2023; 12:2662. [PMID: 37998397 PMCID: PMC10670506 DOI: 10.3390/cells12222662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 10/31/2023] [Accepted: 11/01/2023] [Indexed: 11/25/2023] Open
Abstract
Bardet-Biedl syndrome (BBS) is an archetypal ciliopathy caused by dysfunction of primary cilia. BBS affects multiple tissues, including the kidney, eye and hypothalamic satiety response. Understanding pan-tissue mechanisms of pathogenesis versus those which are tissue-specific, as well as gauging their associated inter-individual variation owing to genetic background and stochastic processes, is of paramount importance in syndromology. The BBSome is a membrane-trafficking and intraflagellar transport (IFT) adaptor protein complex formed by eight BBS proteins, including BBS1, which is the most commonly mutated gene in BBS. To investigate disease pathogenesis, we generated a series of clonal renal collecting duct IMCD3 cell lines carrying defined biallelic nonsense or frameshift mutations in Bbs1, as well as a panel of matching wild-type CRISPR control clones. Using a phenotypic screen and an unbiased multi-omics approach, we note significant clonal variability for all assays, emphasising the importance of analysing panels of genetically defined clones. Our results suggest that BBS1 is required for the suppression of mesenchymal cell identities as the IMCD3 cell passage number increases. This was associated with a failure to express epithelial cell markers and tight junction formation, which was variable amongst clones. Transcriptomic analysis of hypothalamic preparations from BBS mutant mice, as well as BBS patient fibroblasts, suggested that dysregulation of epithelial-to-mesenchymal transition (EMT) genes is a general predisposing feature of BBS across tissues. Collectively, this work suggests that the dynamic stability of the BBSome is essential for the suppression of mesenchymal cell identities as epithelial cells differentiate.
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Affiliation(s)
- Grace Mercedes Freke
- Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK; (G.M.F.); (T.M.); (M.S.); (E.P.); (N.H.); (G.O.); (J.J.S.); (P.L.B.)
| | - Tiago Martins
- Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK; (G.M.F.); (T.M.); (M.S.); (E.P.); (N.H.); (G.O.); (J.J.S.); (P.L.B.)
| | - Rosalind Jane Davies
- Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK; (G.M.F.); (T.M.); (M.S.); (E.P.); (N.H.); (G.O.); (J.J.S.); (P.L.B.)
| | - Tina Beyer
- Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Elfriede-Aulhorn-Strasse 7, 72076 Tübingen, Germany; (T.B.); (M.U.); (K.B.)
| | - Marian Seda
- Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK; (G.M.F.); (T.M.); (M.S.); (E.P.); (N.H.); (G.O.); (J.J.S.); (P.L.B.)
| | - Emma Peskett
- Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK; (G.M.F.); (T.M.); (M.S.); (E.P.); (N.H.); (G.O.); (J.J.S.); (P.L.B.)
| | - Naila Haq
- Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK; (G.M.F.); (T.M.); (M.S.); (E.P.); (N.H.); (G.O.); (J.J.S.); (P.L.B.)
| | - Avishek Prasai
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic (M.H.)
| | - Georg Otto
- Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK; (G.M.F.); (T.M.); (M.S.); (E.P.); (N.H.); (G.O.); (J.J.S.); (P.L.B.)
| | - Jeshmi Jeyabalan Srikaran
- Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK; (G.M.F.); (T.M.); (M.S.); (E.P.); (N.H.); (G.O.); (J.J.S.); (P.L.B.)
| | - Victor Hernandez
- Life Sciences Department, CHMLS, Brunel University London, Kingston Lane, Uxbridge UB8 3PH, UK;
| | - Gaurav D. Diwan
- BioQuant, University of Heidelberg, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany; (G.D.D.); (R.B.R.)
- Biochemistry Center (BZH), University of Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Robert B. Russell
- BioQuant, University of Heidelberg, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany; (G.D.D.); (R.B.R.)
- Biochemistry Center (BZH), University of Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Marius Ueffing
- Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Elfriede-Aulhorn-Strasse 7, 72076 Tübingen, Germany; (T.B.); (M.U.); (K.B.)
| | - Martina Huranova
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic (M.H.)
| | - Karsten Boldt
- Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Elfriede-Aulhorn-Strasse 7, 72076 Tübingen, Germany; (T.B.); (M.U.); (K.B.)
| | - Philip L. Beales
- Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK; (G.M.F.); (T.M.); (M.S.); (E.P.); (N.H.); (G.O.); (J.J.S.); (P.L.B.)
| | - Dagan Jenkins
- Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK; (G.M.F.); (T.M.); (M.S.); (E.P.); (N.H.); (G.O.); (J.J.S.); (P.L.B.)
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Hesketh SJ, Mukhopadhyay AG, Nakamura D, Toropova K, Roberts AJ. IFT-A structure reveals carriages for membrane protein transport into cilia. Cell 2022; 185:4971-4985.e16. [PMID: 36462505 DOI: 10.1016/j.cell.2022.11.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 10/13/2022] [Accepted: 11/09/2022] [Indexed: 12/05/2022]
Abstract
Intraflagellar transport (IFT) trains are massive molecular machines that traffic proteins between cilia and the cell body. Each IFT train is a dynamic polymer of two large complexes (IFT-A and -B) and motor proteins, posing a formidable challenge to mechanistic understanding. Here, we reconstituted the complete human IFT-A complex and obtained its structure using cryo-EM. Combined with AlphaFold prediction and genome-editing studies, our results illuminate how IFT-A polymerizes, interacts with IFT-B, and uses an array of β-propeller and TPR domains to create "carriages" of the IFT train that engage TULP adaptor proteins. We show that IFT-A⋅TULP carriages are essential for cilia localization of diverse membrane proteins, as well as ICK-the key kinase regulating IFT train turnaround. These data establish a structural link between IFT-A's distinct functions, provide a blueprint for IFT-A in the train, and shed light on how IFT evolved from a proto-coatomer ancestor.
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Affiliation(s)
- Sophie J Hesketh
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck University of London, London, WC1E 7HX, UK
| | - Aakash G Mukhopadhyay
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck University of London, London, WC1E 7HX, UK
| | - Dai Nakamura
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck University of London, London, WC1E 7HX, UK
| | - Katerina Toropova
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck University of London, London, WC1E 7HX, UK.
| | - Anthony J Roberts
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck University of London, London, WC1E 7HX, UK.
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