Structural and immunocytochemical alterations in eye lens fiber cells from Cx46 and Cx50 knockout mice.
In the current study we describe the changes of overall organization of lens fiber cells in connexin 46 (Cx46) and connexin 50 (Cx50) knockout mice. Morphometric analyses and the application of immunocytochemical techniques revealed that in Cx46 knockout lens (Cx46 -/-), where Cx50 is expressed alone, the postnatal differentiation of secondary fiber cells proceeds faster and is characterized by an increased number of smaller fiber cells. Conversely, in Cx50 knockout mice (Cx50 -/-), the lenticular mass is considerably reduced and characterized by a small number of fiber cells added during the postnatal period. The process of terminal differentiation was impaired and generated larger fiber cells still possessing cytoplasmic organelles. Freeze-fracture and fracture labeling revealed that the junctional assembly, packing organization and topographic interactions between connexons and MP26 differed when Cx46 and Cx50 were co-assembled in the wild-type or expressed separately in the two distinct knockout phenotypes. Filipin cytochemistry provided indirect evidence that Cx46 and Cx50 expressed alone are recruited into different lipid environments. Our results represent the structural proof that interaction of connexins and MP26 contributes to the overall organization of the fiber cells.
Dunia
Irene
I
Biologie Cellulaire, Institut Jacques Monod, CNRS, Universités Paris 6-Paris 7, 2, place Jussieu, F-75251 Paris Cedex 5, France. dunia@ijm.jussieu.fr
Cibert
Christian
C
Gong
Xiaohua
X
Xia
Chun-hong
CH
Recouvreur
Michel
M
Levy
Essy
E
Kumar
Nalin
N
Bloemendal
Hans
H
Benedetti
E Lucio
EL
D000818:Animals; D002450:Cell Communication / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism / Q000502:physiology; D017630:Connexins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D005614:Freeze Fracturing / Q000379:methods; D017629:Gap Junctions / Q000378:metabolism / Q000502:physiology; D015151:Immunoblotting; D007150:Immunohistochemistry; D007908:Lens, Crystalline / Q000166:cytology* / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D000099264:Connexin 50
D017630:Connexins; D005136:Eye Proteins; D008565:Membrane Proteins; D000099264:Connexin 50; C082917:GJA3 protein, human