Differential expression of N- and B-cadherin during lens development.
OBJECTIVE
To analyze the dynamics of N- and B-cadherin cell adhesion molecule expression and cytoskeletal interaction during embryonic chick lens development.


METHODS
Localization of N- and B-cadherin, F-actin, and connexin 56 were determined by immunohistochemistry of developing lenses or immunocytochemistry of differentiating primary lens cultures. Biochemical analysis of cytoskeletal linkage of N- or B-cadherin was assessed by differential detergent extraction, electrophoresis, and immunoblotting.


RESULTS
The results indicate that although both cadherins are expressed throughout lens development, N-cadherin expression detected was similar in both lens epithelial and fiber cells, whereas B-cadherin was preferentially localized to the lens fiber cells. During differentiation, both cadherins become increasingly associated with the lens cytoskeleton, as indicated biochemically by a transition from largely Triton X-100-soluble to Triton X-100-insoluble pools and immunocytologically by cadherin localization to cell-cell borders and colocalization with the actin cytoskeleton. Although a significant fraction of N-cadherin remains Triton X-100-soluble as the lens cells differentiate, B-cadherin becomes resistant to extraction by both Triton X-100 as well as RIPA buffers. As detected immunocytochemically in lens cell cultures, the temporal localization of N-cadherin to cell-cell interfaces precedes that of B-cadherin. Furthermore, temporal localization of B-cadherin, as opposed to N-cadherin, to cell-cell borders more closely parallels that of connexin 56 in vitro as well as in vivo. CONCLUSIONS; These results suggest that while both N- and B-cadherin are expressed during lens cell differentiation, both their patterns of expression as well as their cytoskeletal association differ between epithelial and fiber cells.
Leong
L
L
Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, Pennsylvania 19107, USA.
Menko
A S
AS
Grunwald
G B
GB
D000199:Actins / Q000378:metabolism*; D000818:Animals; D015820:Cadherins / Q000096:biosynthesis*; D002454:Cell Differentiation; D002642:Chick Embryo / Q000254:growth & development*; D017630:Connexins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005136:Eye Proteins / Q000378:metabolism*; D019084:Fluorescent Antibody Technique, Indirect; D007908:Lens, Crystalline / Q000196:embryology* / Q000378:metabolism
D000199:Actins; D015820:Cadherins; D017630:Connexins; D005136:Eye Proteins; C078866:connexin 56