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Author Notes:

Correspondence and requests for materials should be addressed to H.L. (email: hang. lu@gatech.edu)

H.H., D.B., G.B., S.O. and H.L. designed the study; H.H., Y.M. and D.B. performed research; H.H., G.B., S.O. and H.L. analyzed the data, and H.H., D.B., Y.M., G.B., S.O. and H.L. wrote the paper.

The authors declare no competing financial interests.


Research Funding:

H.L. and G.M.B. gratefully acknowledge the financial support of Human Frontier Science Program (RGP0044/2012).

Additionally, H.L. acknowledges support from the US National Institutes of Health (GM088333, AG035317, and EB012803).

G.M.B. is grateful for support from NIH (AR064307), and S.O. is grateful for support from NIH (AR048615).


  • Science & Technology
  • Multidisciplinary Sciences
  • Science & Technology - Other Topics
  • GENE
  • Engineering
  • Imaging
  • Lab-on-a-chop
  • Optogenetics
  • Physiology

Muscle contraction phenotypic analysis enabled by optogenetics reveals functional relationships of sarcomere components in Caenorhabditis elegans


Journal Title:

Scientific Reports


Volume 6


, Pages 19900-19900

Type of Work:

Article | Final Publisher PDF


The sarcomere, the fundamental unit of muscle contraction, is a highly-ordered complex of hundreds of proteins. Despite decades of genetics work, the functional relationships and the roles of those sarcomeric proteins in animal behaviors remain unclear. In this paper, we demonstrate that optogenetic activation of the motor neurons that induce muscle contraction can facilitate quantitative studies of muscle kinetics in C. elegans. To increase the throughput of the study, we trapped multiple worms in parallel in a microfluidic device and illuminated for photoactivation of channelrhodopsin-2 to induce contractions in body wall muscles. Using image processing, the change in body size was quantified over time. A total of five parameters including rate constants for contraction and relaxation were extracted from the optogenetic assay as descriptors of sarcomere functions. To potentially relate the genes encoding the sarcomeric proteins functionally, a hierarchical clustering analysis was conducted on the basis of those parameters. Because it assesses physiological output different from conventional assays, this method provides a complement to the phenotypic analysis of C. elegans muscle mutants currently performed in many labs; the clusters may provide new insights and drive new hypotheses for functional relationships among the many sarcomere components.

Copyright information:

This is an Open Access work distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/).

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