Temporal and spatial patterns of phosphotyrosine immunolocalization during cardiac myofibrillogenesis of the chicken embryo.
To investigate the possible role of phosphorylation of protein tyrosine during myofibrillogenesis (6- to 13-somite stages) of the chicken embryonic heart tube, immunolocalization of phosphotyrosine (P-Tyr) and the relationship between P-Tyr and developing myofibrils were studied by means of confocal scanning laser microscopy and immuno-electron microscopy. The staining pattern of P-Tyr varied in different sites of myocytes at different stages of embryonic development: At the cell-cell boundaries, P-Tyr was localized at the adhesion belt of outer myocardial layer cells (6- to 13-somite stages), non-junctional cell-cell contacts (6- to 13-somite stages) and early intercalated disks of both the outer and inner myocardial layer cells (8- to 13-somite stages). At the cell-extracellular matrix boundaries of inner layer cells, the first stages of myofibril formation appeared as serially aligned areas of P-Tyr localization closely associated with circumferentially aligned thick actin bundles (8- to 9-somite stages). This P-Tyr immunostaining decreased when the thick actin bundles developed into mature striated myofibrils at the 10- to 13-somite stages. These findings suggest that the phosphorylation of protein tyrosine residues is primarily concentrated at the modulating cell-cell and cell-matrix adhesion sites of developing myocytes and myofibrils.
Shiraishi
I
I
Department of Pathology, Kyoto Prefectural University of Medicine, Japan.
Takamatsu
T
T
Price
R L
RL
Fujita
S
S
D000199:Actins / Q000032:analysis; D000818:Animals; D002448:Cell Adhesion; D002642:Chick Embryo; D006321:Heart / Q000196:embryology*; D007150:Immunohistochemistry; D007365:Intercellular Junctions / Q000378:metabolism; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D009206:Myocardium / Q000737:chemistry / Q000378:metabolism*; D009210:Myofibrils / Q000737:chemistry / Q000378:metabolism*; D019000:Phosphotyrosine / Q000378:metabolism* / Q000502:physiology; D013997:Time Factors; D014018:Tissue Distribution
D000199:Actins; D019000:Phosphotyrosine