Prenatal lens development in connexin43 and connexin50 double knockout mice.
OBJECTIVE
To determine the roles of intercellular communication in embryonic eye growth and development, mice with a targeted deletion of the Cx43 gene were examined, and mice without both Cx43 and Cx50 were generated and analyzed.


METHODS
Embryonic eyes and lenses from wild-type mice, or mice deficient in Cx43, Cx50, or both Cx43 and Cx50 were collected and analyzed structurally by light and electron microscopy, immunohistochemically using connexin-specific antibodies, biochemically by Western blot analysis, and physiologically by measuring patterns of junctional communication revealed by iontophoretic injection of junction-permeable reporter molecules.


RESULTS
Cx50 expression was limited to the ocular lens and was not detected in either the cornea or the retina. Cx43(-/-) embryos showed development of structurally normal lenses and eyes when examined by light and electron microscopy through embryonic day (E)18.5. In addition, Cx43(-/-) lenses synthesized four different markers of lens differentiation: MIP26, alphaA-crystallin, alphaB-crystallin, and gamma-crystallin. Double-knockout lenses were also histologically normal through E18.5 and synthesized the four lens differentiation markers. When assayed by intracellular injection with Lucifer yellow (Molecular Probes, Eugene, OR) and neurobiotin at E15.5, Cx43(-/-)/Cx50(-/-) lenses retained gap junction-mediated dye transfer between fiber cells. In contrast, dye transfer in double-knockout lenses was dramatically reduced between epithelial cells and was eliminated between epithelial cells and fibers.


CONCLUSIONS
These data indicate that the unique functional properties of both Cx43 and Cx50 are not required for prenatal lens development and that connexin diversity is required for regulation of postnatal growth and homeostasis.
White
T W
TW
Department of Physiology and Biophysics, State University of New York, Stony Brook 11794-8661, USA. thomas.white@sunysb.edu
Sellitto
C
C
Paul
D L
DL
Goodenough
D A
DA
D000818:Animals; D020346:Aquaporins; D001710:Biotin / Q000031:analogs & derivatives* / Q000378:metabolism; D015153:Blotting, Western; D002454:Cell Differentiation / Q000502:physiology; D018031:Connexin 43 / Q000502:physiology*; D017630:Connexins; D003459:Crystallins / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D005123:Eye / Q000254:growth & development; D005136:Eye Proteins / Q000378:metabolism / Q000502:physiology*; D005260:Female; D017629:Gap Junctions / Q000502:physiology; D017353:Gene Deletion; D007546:Isoquinolines / Q000378:metabolism; D007908:Lens, Crystalline / Q000196:embryology* / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D000099264:Connexin 50
D020346:Aquaporins; D001710:Biotin; D018031:Connexin 43; D017630:Connexins; D003459:Crystallins; D005136:Eye Proteins; D007546:Isoquinolines; D008562:Membrane Glycoproteins; D000099264:Connexin 50; C030328:aquaporin 0; C070614:neurobiotin; C017475:lucifer yellow