Cultured chicken embryo lens cells resemble differentiating fiber cells in vivo and contain two kinetic pools of connexin56.
The lens is an avascular organ in which gap junctions play a pivotal role for cell physiology and transparency. Here we evaluate a lens culture system as a model for studies of lens gap junction dynamics. In culture, chicken embryo lens cells initially form a monolayer of epithelial cells. Subsequently, the epithelial cells differentiate into lentoids, birefringent multicellular structures composed of fiber-like cells. We examined the cultures for the expression of cellular markers and lens fiber specific proteins using immunofluorescence and immunoblot analysis. We also determined the half-life of connexin56 (Cx56), a fiber-specific gap junction protein. All lens cells in culture expressed actin, endoplasmic reticulum proteins and N-cadherin. Only lentoid cells expressed the lens fiber connexins, Cx45.6 and Cx56. Cx56 localized at appositional membranes and did not co-localize with endoplasmic reticulum proteins or N-cadherin. Two pools of Cx56 were detected in these cultures, one with a half-life of a few hours and the other with a half-life of days. The two pools contained phosphorylated forms of Cx56 of different apparent molecular weights. These results suggest that lens cells in culture can be used as a model for the study of lens biology. They also suggest that phosphorylation of Cx56 might be regulating the stability of the protein.
Berthoud
V M
VM
Department of Pediatrics, University of Chicago, Chicago, IL 60637, USA.
Bassnett
S
S
Beyer
E C
EC
D000818:Animals; D015415:Biomarkers; D002478:Cells, Cultured; D002642:Chick Embryo; D017630:Connexins / Q000032:analysis / Q000378:metabolism*; D005136:Eye Proteins / Q000032:analysis / Q000378:metabolism*; D017629:Gap Junctions / Q000378:metabolism*; D006207:Half-Life; D015151:Immunoblotting; D007150:Immunohistochemistry; D007908:Lens, Crystalline / Q000737:chemistry / Q000166:cytology*; D008954:Models, Biological; D008970:Molecular Weight
D015415:Biomarkers; D017630:Connexins; D005136:Eye Proteins; C078866:connexin 56