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Christophers B, Leahy SN, Soffar DB, von Saucken VE, Broadie K, Baylies MK. Muscle cofilin alters neuromuscular junction postsynaptic development to strengthen functional neurotransmission. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.21.568166. [PMID: 38045306 PMCID: PMC10690168 DOI: 10.1101/2023.11.21.568166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Cofilin, an actin severing protein, plays critical roles in muscle sarcomere addition and maintenance. Our previous work has shown Drosophila cofilin (DmCFL) knockdown causes progressive deterioration of muscle structure and function and produces features seen in nemaline myopathy (NM) caused by cofilin mutations. We hypothesized that disruption of actin cytoskeleton dynamics by DmCFL knockdown would impact other aspects of muscle development, and, thus, conducted an RNA sequencing analysis which unexpectedly revealed upregulated expression of numerous neuromuscular junction (NMJ) genes. We found that DmCFL is enriched in the muscle postsynaptic compartment and that DmCFL deficiency causes F-actin disorganization in this subcellular domain prior to the sarcomere defects observed later in development. Despite NMJ gene expression changes, we found no significant changes in gross presynaptic Bruchpilot active zones or total postsynaptic glutamate receptor levels. However, DmCFL knockdown results in mislocalization of glutamate receptors containing the GluRIIA subunit in more deteriorated muscles and neurotransmission strength is strongly impaired. These findings expand our understanding of cofilin's roles in muscle to include NMJ structural development and suggest that NMJ defects may contribute to NM pathophysiology.
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Affiliation(s)
- Briana Christophers
- Weill Cornell–Rockefeller–Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY, 10065, USA
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Shannon N. Leahy
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - David B. Soffar
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Victoria E. von Saucken
- Weill Cornell–Rockefeller–Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY, 10065, USA
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
- Kennedy Center for Research on Human Development, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
- Vanderbilt Brain Institute, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - Mary K. Baylies
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
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Balakrishnan M, Sisso WJ, Baylies MK. Analyzing muscle structure and function throughout the larval instars in live Drosophila. STAR Protoc 2021; 2:100291. [PMID: 33532738 PMCID: PMC7821049 DOI: 10.1016/j.xpro.2020.100291] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Drosophila larval musculature is a genetically and optically accessible system to study muscle development. Each larval muscle is a single fiber with conserved cytoarchitecture, including its sarcomere structure and composition. Here, we present a workflow for systematically analyzing muscle structure and function at discrete larval stages, as well as throughout the larval instars, using both newly developed and adapted methods. For complete details on the use and execution of this protocol, please refer to Balakrishnan et al. (2020). Detailed methods for preparation and analysis of Drosophila larval muscle structure Methods for muscle structure and function analysis in the same larva over time Steps for analyzing sarcomere size and organization Pitfalls and troubleshooting approaches described
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Affiliation(s)
- Mridula Balakrishnan
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA.,Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Whitney J Sisso
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA.,Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Mary K Baylies
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA.,Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
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