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ZFIN ID: ZDB-PUB-160602-1
In vivo myosin step-size from zebrafish skeletal muscle
Burghardt, T.P., Ajtai, K., Sun, X., Takubo, N., Wang, Y.
Date: 2016
Source: Open Biology 6(5): (Journal)
Registered Authors: Burghardt, Thomas P., Sun, Xiaojing
Keywords: highly inclined thin illumination, single myosin detection in vivo, strychnine induced contraction, transgenic zebrafish skeletal muscle, zebrafish skeletal myosin powerstroke, zebrafish skeletal myosin step-size
MeSH Terms:
  • Actins/metabolism
  • Adenosine Triphosphate/metabolism
  • Animals
  • Animals, Genetically Modified
  • Binding Sites
  • Green Fluorescent Proteins/metabolism
  • Humans
  • Muscle, Skeletal/drug effects
  • Muscle, Skeletal/embryology*
  • Muscle, Skeletal/metabolism
  • Myosin Light Chains/chemistry*
  • Myosin Light Chains/genetics
  • Myosin Light Chains/metabolism*
  • Strychnine/pharmacology
  • Zebrafish/embryology
  • Zebrafish/genetics*
PubMed: 27249818 Full text @ Open Biol.
ABSTRACT
Muscle myosins transduce ATP free energy into actin displacement to power contraction. In vivo, myosin side chains are modified post-translationally under native conditions, potentially impacting function. Single myosin detection provides the 'bottom-up' myosin characterization probing basic mechanisms without ambiguities inherent to ensemble observation. Macroscopic muscle physiological experimentation provides the definitive 'top-down' phenotype characterizations that are the concerns in translational medicine. In vivo single myosin detection in muscle from zebrafish embryo models for human muscle fulfils ambitions for both bottom-up and top-down experimentation. A photoactivatable green fluorescent protein (GFP)-tagged myosin light chain expressed in transgenic zebrafish skeletal muscle specifically modifies the myosin lever-arm. Strychnine induces the simultaneous contraction of the bilateral tail muscles in a live embryo, causing them to be isometric while active. Highly inclined thin illumination excites the GFP tag of single lever-arms and its super-resolution orientation is measured from an active isometric muscle over a time sequence covering many transduction cycles. Consecutive frame lever-arm angular displacement converts to step-size by its product with the estimated lever-arm length. About 17% of the active myosin steps that fall between 2 and 7 nm are implicated as powerstrokes because they are beyond displacements detected from either relaxed or ATP-depleted (rigor) muscle.
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