The mechanism of cell elongation during lens fiber cell differentiation
1982; Elsevier BV; Volume: 92; Issue: 1 Linguagem: Inglês
10.1016/0012-1606(82)90149-x
ISSN1095-564X
AutoresDavid C. Beebe, Pamela J. Compart, Martha C. Johnson, Douglas E. Feagans, Richard N. Feinberg,
Tópico(s)Barrier Structure and Function Studies
ResumoLens fiber formation is characterized by extensive cell elongation. Earlier studies have shown that lens cell elongation in vitro can occur in the absence of microtubules and is associated with a proportional increase in cell volume. We have previously suggested that lens fiber cell elongation is directly caused by an increase in cell volume. In this report, lenses from 3- and 6-day-old chicken embryos were three-dimensionally reconstructed from serial sections to provide a measure of cell volume and length during various stages of primary and secondary lens fiber formation. In both cases, cell volume was highly correlated with cell length during lens cell elongation. In addition, during primary lens fiber formation, large intercellular spaces between lens vesicle cells disappeared as these cells began to elongate to form lens fibers. Loss of intercellular spaces would be expected if increasing cell volume were responsible for cell elongation. Finally, results of experiments in which the lens capsule was cut with a fine tungsten needle suggested that the capsule was elastic and normally under tension. These findings were used to formulate a model which accounts for the major events in lens morphogenesis based on (1) the regulation of cell volume, (2) the junctions present between lens cells, and (3) the constraint provided by the elasticity of the lens capsule.
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