TY - JOUR
T1 - Resisting the effects of aging
T2 - A function for the fiber cell beaded filament
AU - Yoon, Kyoung Hye
AU - Blankenship, Tom
AU - Shibata, Bradley
AU - FitzGerald, Paul G
PY - 2008/3
Y1 - 2008/3
N2 - PURPOSE. The beaded filament is a cytoskeletal structure that has been found only in the lens fiber cell. It includes phakosin and filensin, two divergent members of the intermediate filament family of proteins that are also unique to the fiber cell. The authors sought to determine what function the beaded filament fulfills in the lens. METHODS. Light microscopy and electron microscopy were used to characterize structural changes that occurred in previously generated phakosin and filensin knockout mice. Immunocytochemistry and electron microscopy were used to define the distribution of phakosin, filensin, and beaded filaments. RESULTS. In phakosin and filensin knockout mice, initial lens development and the early phases of fiber cell differentiation proceed in a manner largely indistinguishable from that of wild type. Fiber cells elongate, undergo organelle elimination, and, in the organelle-free zone, develop the unique paddlelike extensions that characterize cells in this region. Subsequent to those stages, however, fiber cells undergo loss of the differentiated fiber cell phenotype and loss of the long-range stacking that characterizes fiber cells and that has been considered essential for clarity. CONCLUSIONS. The beaded filament is not required for the generation of the differentiated fiber cell phenotype but is required to maintain that differentiated state and the long range order that characterizes the lens at the tissue level.
AB - PURPOSE. The beaded filament is a cytoskeletal structure that has been found only in the lens fiber cell. It includes phakosin and filensin, two divergent members of the intermediate filament family of proteins that are also unique to the fiber cell. The authors sought to determine what function the beaded filament fulfills in the lens. METHODS. Light microscopy and electron microscopy were used to characterize structural changes that occurred in previously generated phakosin and filensin knockout mice. Immunocytochemistry and electron microscopy were used to define the distribution of phakosin, filensin, and beaded filaments. RESULTS. In phakosin and filensin knockout mice, initial lens development and the early phases of fiber cell differentiation proceed in a manner largely indistinguishable from that of wild type. Fiber cells elongate, undergo organelle elimination, and, in the organelle-free zone, develop the unique paddlelike extensions that characterize cells in this region. Subsequent to those stages, however, fiber cells undergo loss of the differentiated fiber cell phenotype and loss of the long-range stacking that characterizes fiber cells and that has been considered essential for clarity. CONCLUSIONS. The beaded filament is not required for the generation of the differentiated fiber cell phenotype but is required to maintain that differentiated state and the long range order that characterizes the lens at the tissue level.
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U2 - 10.1167/iovs.07-1149
DO - 10.1167/iovs.07-1149
M3 - Article
C2 - 18326727
AN - SCOPUS:41949122572
VL - 49
SP - 1030
EP - 1036
JO - Investigative Ophthalmology and Visual Science
JF - Investigative Ophthalmology and Visual Science
SN - 0146-0404
IS - 3
ER -