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Developmental Biology

Optogenetic Inhibition of Rho1-Mediated Actomyosin Contractility Coupled with Measurement of Epithelial Tension in Drosophila Embryos

Published: April 14th, 2023



1Department of Biological Sciences, Dartmouth College, 2School of Life Sciences, Westlake University, 3Department of Molecular Biology, Princeton University

Actomyosin contractility plays an important role in cell and tissue morphogenesis. However, it is challenging to manipulate actomyosin contractility in vivo acutely. This protocol describes an optogenetic system that rapidly inhibits Rho1-mediated actomyosin contractility in Drosophila embryos, revealing the immediate loss of epithelial tension after the inactivation of actomyosin in vivo.

Contractile forces generated by actin and non-muscle myosin II ("actomyosin contractility") are critical for morphological changes of cells and tissues at multiple length scales, such as cell division, cell migration, epithelial folding, and branching morphogenesis. An in-depth understanding of the role of actomyosin contractility in morphogenesis requires approaches that allow the rapid inactivation of actomyosin, which is difficult to achieve using conventional genetic or pharmacological approaches. The presented protocol demonstrates the use of a CRY2-CIBN based optogenetic dimerization system, Opto-Rho1DN, to inhibit actomyosin contractility in Drosophila embryos with precise temporal and spatial controls. In this system, CRY2 is fused to the dominant negative form of Rho1 (Rho1DN), whereas CIBN is anchored to the plasma membrane. Blue light-mediated dimerization of CRY2 and CIBN results in rapid translocation of Rho1DN from the cytoplasm to the plasma membrane, where it inactivates actomyosin by inhibiting endogenous Rho1. In addition, this article presents a detailed protocol for coupling Opto-Rho1DN-mediated inactivation of actomyosin with laser ablation to investigate the role of actomyosin in generating epithelial tension during Drosophila ventral furrow formation. This protocol can be applied to many other morphological processes that involve actomyosin contractility in Drosophila embryos with minimal modifications. Overall, this optogenetic tool is a powerful approach to dissect the function of actomyosin contractility in controlling tissue mechanics during dynamic tissue remodeling.

Actomyosin contractility, the contractile force exerted by non-muscle myosin II (hereafter 'myosin') on the F-actin network, is one of the most important forces in changing cell shape and driving tissue-level morphogenesis1,2. For example, the activation of actomyosin contractility at the apical domain of the epithelial cells results in apical constriction, which facilitates a variety of morphogenetic processes, including epithelial folding, cell extrusion, delamination, and wound healing3,4,5,

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1. Setting up the genetic cross and preparing the egg collection cup

  1. Select female flies (virgin) from the optogenetic line UASp-CIBNpm (I); UASp-CRY2-Rho1DN-mCherry (III) on a CO2 pad under a stereomicroscope and set up a cross with male flies from the maternal GAL4 driver line 67 Sqh-mCherry; 15 E-cadherin-GFP.
    NOTE: The 67 and 15 stand for maternal-Tubulin-GAL4 inserted into the second (II) and third (III) chromosomes, respectively52. The GAL4 line.......

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In the unstimulated embryos undergoing apical constriction, Sqh-mCherry became enriched at the medioapical region of the ventral mesodermal cells, whereas CRY2-Rho1DN-mCherry was cytosolic (Figure 1A). Laser ablation within the constriction domain led to a rapid tissue recoil along the A-P axis (Figure 1B,C). In the stimulated embryos, the CRY2-Rho1DN-mCherry signal became plasma membrane localized, whereas the medioapical signal of Sqh-mCherry .......

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This protocol described the combined use of optogenetics and laser ablation to probe changes in tissue tension immediately after the inactivation of actomyosin contractility. The optogenetic tool described here takes advantage of the dominant negative form of Rho1 (Rho1DN) to acutely inhibit endogenous Rho1 and Rho1-dependent actomyosin contractility. Previous characterization of Opto-Rho1DN in the context of Drosophila ventral furrow formation demonstrated that the tool is highly effective in mediating the rapi.......

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The authors thank Ann Lavanway for imaging support. The authors thank the Wieschaus lab and the De Renzis lab for sharing reagents and the Bloomington Drosophila Stock Center for fly stocks. This study is supported by NIGMS ESI-MIRA R35GM128745 and American Cancer Society Institutional Research Grant #IRG-82-003-33 to BH.


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NameCompanyCatalog NumberComments
35 mm glass-bottom dishMatTekP35G-1.5-10-CUsed for sample preparation
60 mm × 15 mm Petri dish with lidFalcon351007Used for sample preparation
Black cloth for covering the microscopeOnlineNAUsed to avoid unwanted light stimulation
Clorox Ultra Germicadal Bleach (8.25% sodium hypochlorite)VWR10028-048Used for embryo dechorination
CO2 padGenesee Scientific59-114Used for cross set-up
ddH2ONANAUsed for sample preparation
Dumont Style 5 tweezersVWR102091-654Used for sample preparation
Eyelash tool (made from pure red sable round brush #2)VWR22940-834Used for sample preparation
FluoView (Software)OlympusNAUsed for image acquisition and optogenetic stimulation
Halocarbon oil 27Sigma AldrichH8773-100MLUsed for embryo stage visualization
ImageJ/FIJINIHNAUsed for image analysis
MATLABMathWorksNAUsed for image analysis
Nikon SMZ-745 stereoscopeNikonNAUsed for sample preparation
Olympus FVMPE-RS multiphoton microscope with InSight DS Dual-line Ultrafast Lasers for simultaneous dual-wavelength multiphoton imaging, , a 25x/NA1.05 water immersion objective (XLPLN25XWMP2), and an IR/VIS stimulation unit for photo-activation/stimulation. This system is also equipped with a TRITC filter (39005-BX3; AT-TRICT-REDSHFT 540/25x, 565BS, 620/60M), and a fluorescence illumination unit that emits white light.OlympusNAUsed for image acquisition and optogenetic stimulation
SP Bel-Art 100-place polypropylene freezer storage box (Black, light-proof box for sample transfer)VWR30621-392Used to avoid unwanted light stimulation
UV Filter Shield for FM1403 Fluores (Orange-red plastic shield)BoliopticsFM14036151Used to avoid unwanted light stimulation
VITCHELO V800 Headlamp with White and Red LED LightsAmazonNAUsed to avoid unwanted light stimulation

  1. Vicente-Manzanares, M., Ma, X., Adelstein, R. S., Horwitz, A. R. Non-muscle myosin II takes centre stage in cell adhesion and migration. Nature Reviews. Molecular Cell Biology. 10 (11), 778-790 (2009).
  2. Munjal, A., Lecuit, T. Actomyosin networks and tissue morphogenesis. Development. 141 (9), 1789-1793 (2014).
  3. Sawyer, J. M., et al. Apical constriction: a cell shape change that can drive morphogenesis. Developmental Biology. 341 (1), 5-19 (2010).
  4. Nishimura, T., Honda, H., Takeichi, M. Planar cell polarity links axes of spatial dynamics in neural-tube closure. Cell. 149 (5), 1084-1097 (2012).
  5. Marinari, E., et al. Live-cell delamination counterbalances epithelial growth to limit tissue overcrowding. Nature. 484 (7395), 542-545 (2012).
  6. Slattum, G. M., Rosenblatt, J. Tumour cell invasion: an emerging role for basal epithelial cell extrusion. Nature Reviews. Cancer. 14 (7), 495-501 (2014).
  7. Antunes, M., Pereira, T., Cordeiro, J. V., Almeida, L., Jacinto, A. Coordinated waves of actomyosin flow and apical cell constriction immediately after wounding. The Journal of Cell Biology. 202 (2), 365-379 (2013).
  8. Yang, S., et al. The central role of the tail in switching off 10S myosin II activity. The Journal of General Physiology. 151 (9), 1081-1093 (2019).
  9. Yang, S., et al. Cryo-EM structure of the inhibited (10S) form of myosin II. Nature. 588 (7838), 521-525 (2020).
  10. Narumiya, S., Thumkeo, D. Rho signaling research: history, current status and future directions. FEBS Letters. 592 (11), 1763-1776 (2018).
  11. Johndrow, J. E., Magie, C. R., Parkhurst, S. M. Rho GTPase function in flies: insights from a developmental and organismal perspective. Biochemistry and Cell Biology. 82 (6), 643-657 (2004).
  12. Etienne-Manneville, S., Hall, A. Rho GTPases in cell biology. Nature. 420 (6916), 629-635 (2002).
  13. Hodge, R. G., Ridley, A. J. Regulating Rho GTPases and their regulators. Nature Reviews. Molecular Cell Biology. 17 (8), 496-510 (2016).
  14. Martin, A. C., Goldstein, B. Apical constriction: themes and variations on a cellular mechanism driving morphogenesis. Development. 141 (10), 1987-1998 (2014).
  15. Amano, M., Nakayama, M., Kaibuchi, K. Rho-kinase/ROCK: A key regulator of the cytoskeleton and cell polarity. Cytoskeleton. 67 (9), 545-554 (2010).
  16. Kimura, K., et al. Regulation of myosin phosphatase by Rho and Rho-associated kinase (Rho-kinase). Science. 273 (5272), 245-248 (1996).
  17. Maekawa, M., et al. Signaling from Rho to the actin cytoskeleton through protein kinases ROCK and LIM-kinase. Science. 285 (5429), 895-898 (1999).
  18. Ohashi, K., et al. Rho-associated kinase ROCK activates LIM-kinase 1 by phosphorylation at threonine 508 within the activation loop. The Journal of Biological Chemistry. 275 (5), 3577-3582 (2000).
  19. Coravos, J. S., Martin, A. C. Apical sarcomere-like actomyosin contracts nonmuscle drosophila epithelial cells. Developmental Cell. 39 (3), 346-358 (2016).
  20. Homem, C. C. F., Peifer, M. Diaphanous regulates myosin and adherens junctions to control cell contractility and protrusive behavior during morphogenesis. Development. 135 (6), 1005-1018 (2008).
  21. Goode, B. L., Eck, M. J. Mechanism and function of formins in the control of actin assembly. Annual Review of Biochemistry. 76, 593-627 (2007).
  22. Sweeton, D., Parks, S., Costa, M., Wieschaus, E. Gastrulation in Drosophila: the formation of the ventral furrow and posterior midgut invaginations. Development. 112 (3), 775-789 (1991).
  23. Leptin, M., Grunewald, B. Cell shape changes during gastrulation in Drosophila. Development. 110 (1), 73-84 (1990).
  24. Leptin, M. Gastrulation in Drosophila: the logic and the cellular mechanisms. The EMBO Journal. 18 (12), 3187-3192 (1999).
  25. Martin, A. C. The physical mechanisms of Drosophila gastrulation: mesoderm and endoderm invagination. Genetics. 214 (3), 543-560 (2020).
  26. Gilmour, D., Rembold, M., Leptin, M. From morphogen to morphogenesis and back. Nature. 541 (7637), 311-320 (2017).
  27. Gheisari, E., Aakhte, M., Müller, H. -. A. J. Gastrulation in Drosophila melanogaster: Genetic control, cellular basis and biomechanics. Mechanisms of Development. 163, 103629 (2020).
  28. Leptin, M. Twist and snail as positive and negative regulators during Drosophila mesoderm development. Genes & Development. 5 (9), 1568-1576 (1991).
  29. Costa, M., Wilson, E. T., Wieschaus, E. A putative cell signal encoded by the folded gastrulation gene coordinates cell shape changes during Drosophila gastrulation. Cell. 76 (6), 1075-1089 (1994).
  30. Kerridge, S., et al. Modular activation of Rho1 by GPCR signalling imparts polarized myosin II activation during morphogenesis. Nature Cell Biology. 18 (3), 261-270 (2016).
  31. Kölsch, V., Seher, T., Fernandez-Ballester, G. J., Serrano, L., Leptin, M. Control of Drosophila gastrulation by apical localization of adherens junctions and RhoGEF2. Science. 315 (5810), 384-386 (2007).
  32. Manning, A. J., Peters, K. A., Peifer, M., Rogers, S. L. Regulation of epithelial morphogenesis by the G protein-coupled receptor mist and its ligand fog. Science Signaling. 6 (301), (2013).
  33. Parks, S., Wieschaus, E. The Drosophila gastrulation gene concertina encodes a G alpha-like protein. Cell. 64 (2), 447-458 (1991).
  34. Barrett, K., Leptin, M., Settleman, J. The Rho GTPase and a putative RhoGEF mediate a signaling pathway for the cell shape changes in Drosophila gastrulation. Cell. 91 (7), 905-915 (1997).
  35. Dawes-Hoang, R. E., et al. Folded gastrulation, cell shape change and the control of myosin localization. Development. 132 (18), 4165-4178 (2005).
  36. Häcker, U., Perrimon, N. DRhoGEF2 encodes a member of the Dbl family of oncogenes and controls cell shape changes during gastrulation in Drosophila. Genes & Development. 12 (2), 274-284 (1998).
  37. Martin, A. C., Kaschube, M., Wieschaus, E. F. Pulsed contractions of an actin-myosin network drive apical constriction. Nature. 457 (7228), 495-499 (2009).
  38. Mason, F. M., Tworoger, M., Martin, A. C. Apical domain polarization localizes actin-myosin activity to drive ratchet-like apical constriction. Nature Cell Biology. 15 (8), 926-936 (2013).
  39. Nikolaidou, K. K., Barrett, K. A Rho GTPase signaling pathway is used reiteratively in epithelial folding and potentially selects the outcome of Rho activation. Current Biology. 14 (20), 1822-1826 (2004).
  40. Martin, A. C., Gelbart, M., Fernandez-Gonzalez, R., Kaschube, M., Wieschaus, E. F. Integration of contractile forces during tissue invagination. The Journal of Cell Biology. 188 (5), 735-749 (2010).
  41. Guo, H., Swan, M., He, B. Optogenetic inhibition of actomyosin reveals mechanical bistability of the mesoderm epithelium during Drosophila mesoderm invagination. eLife. 11, e69082 (2022).
  42. Sebti, S. M., Der, C. J. Searching for the elusive targets of farnesyltransferase inhibitors. Nature Reviews. Cancer. 3 (12), 945-951 (2003).
  43. Roberts, P. J., et al. Rho family GTPase modification and dependence on CAAX motif-signaled posttranslational modification. The Journal of Biological Chemistry. 283 (37), 25150-25163 (2008).
  44. Feig, L. A., Cooper, G. M. Inhibition of NIH 3T3 cell proliferation by a mutant ras protein with preferential affinity for GDP. Molecular and Cellular Biology. 8 (8), 3235-3243 (1988).
  45. Liu, H., et al. Photoexcited CRY2 interacts with CIB1 to regulate transcription and floral initiation in Arabidopsis. Science. 322 (5907), 1535-1539 (2008).
  46. Kennedy, M. J., et al. Rapid blue-light-mediated induction of protein interactions in living cells. Nature Methods. 7 (12), 973-975 (2010).
  47. Guglielmi, G., Barry, J. D., Huber, W., De Renzis, S. An optogenetic method to modulate cell contractility during tissue morphogenesis. Developmental Cell. 35 (5), 646-660 (2015).
  48. Izquierdo, E., Quinkler, T., De Renzis, S. Guided morphogenesis through optogenetic activation of Rho signalling during early Drosophila embryogenesis. Nature Communications. 9 (1), 2366 (2018).
  49. Hutson, M. S., et al. Forces for morphogenesis investigated with laser microsurgery and quantitative modeling. Science. 300 (5616), 145-149 (2003).
  50. Rauzi, M., Lenne, P. -. F. Probing cell mechanics with subcellular laser dissection of actomyosin networks in the early developing Drosophila embryo. Methods in Molecular Biology. 1189, 209-218 (2015).
  51. Rauzi, M., Verant, P., Lecuit, T., Lenne, P. -. F. Nature and anisotropy of cortical forces orienting Drosophila tissue morphogenesis. Nature Cell Biology. 10 (12), 1401-1410 (2008).
  52. Hunter, C., Wieschaus, E. Regulated expression of nullo is required for the formation of distinct apical and basal adherens junctions in the Drosophila blastoderm. The Journal of Cell Biology. 150 (2), 391-401 (2000).
  53. Oda, H., Tsukita, S. Real-time imaging of cell-cell adherens junctions reveals that Drosophila mesoderm invagination begins with two phases of apical constriction of cells. Journal of Cell Science. 114, 493-501 (2001).
  54. Munjal, A., Philippe, J. -. M., Munro, E., Lecuit, T. A self-organized biomechanical network drives shape changes during tissue morphogenesis. Nature. 524 (7565), 351-355 (2015).
  55. Rørth, P. Gal4 in the Drosophila female germline. Mechanisms of Development. 78 (1-2), 113-118 (1998).
  56. Brand, A. H., Perrimon, N. Targeted gene expression as a means of altering cell fates and generating dominant phenotypes. Development. 118 (2), 401-415 (1993).
  57. Magie, C. R., Meyer, M. R., Gorsuch, M. S., Parkhurst, S. M. Mutations in the Rho1 small GTPase disrupt morphogenesis and segmentation during early Drosophila development. Development. 126 (23), 5353-5364 (1999).
  58. Rich, A., Fehon, R. G., Glotzer, M. Rho1 activation recapitulates early gastrulation events in the ventral, but not dorsal, epithelium of Drosophila embryos. eLife. 9, e56893 (2020).
  59. Herrera-Perez, R. M., Cupo, C., Allan, C., Lin, A., Kasza, K. E. Using optogenetics to link myosin patterns to contractile cell behaviors during convergent extension. Biophysical Journal. 120 (19), 4214-4229 (2021).

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