title: Myosin filament assembly onto myofibrils in live neonatal cardiomyocytes observed by TPEF-SHG microscopy.
abstract: OBJECTIVE
  Understanding myofibrillogenesis is essential for elucidating heart muscle formation, development, and remodelling in response to physiological stimulation. Here, we report the dynamic assembly process of contractile myosin filaments onto myofibrils in a live cardiomyocyte culture during myofibrillogenesis.
  
  
  RESULTS
  Utilizing a custom-built, two-photon excitation fluorescence and second harmonic generation imaging system equipped with an on-stage incubator, we observed new sarcomere additions in rat neonatal cardiomyocytes during 10 h of on-stage incubation. The new sarcomere additions occurred at the side of existing myofibrils, where we observed mature myofibrils acting as templates, or at the interstice of several separated myofibrils.
  
  
  CONCLUSIONS
  During sarcomeric addition, myosin filaments are assembled onto the premyofibril laterally. This lateral addition, which proceeds stepwise along the axial direction, plays an important role in the accumulation of Z-bodies to form mature Z-disks and in the regulation of sarcomeric alignment during maturation.
authors.affiliation: Department of Bioengineering and COMSET,  Clemson University, Clemson, SC 29634,  USA.
authors.forename: Honghai
authors.initials: H
authors.lastname: Liu
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Shao
authors.forename: Wan
authors.initials: W
authors.lastname: Qin
authors.forename: Raymond B
authors.initials: RB
authors.lastname: Runyan
authors.forename: Meifeng
authors.initials: M
authors.lastname: Xu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Ma
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Borg
authors.forename: Roger
authors.initials: R
authors.lastname: Markwald
authors.forename: Bruce Z
authors.initials: BZ
authors.lastname: Gao
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D018613:Microscopy, Confocal; D024510:Muscle Development; D032383:Myocytes, Cardiac / Q000648:ultrastructure*; D009210:Myofibrils / Q000648:ultrastructure; D009218:Myosins / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012518:Sarcomeres / Q000648:ultrastructure
chemical_list: D009218:Myosins