Differentiation of lens cells: changes in connexin expression lead
to increased gap junctional voltage dependence and conductance.
Donaldson, Paul J., Yimin Dong, Marc Roos, Colin Green, Daniel A.
Goodenough, and Joerg Kistler.
Centre for Gene Technology, School of Biological Sciences,
Department of Anatomy, School of Medicine, University of Auckland,
Auckland, New Zealand; and Department of Cell Biology, Harvard
Medical School, Boston, Massachusetts 02115, USA
APStracts 2:0130C, 1995.
The differentiation of mouse lens epithelial cells into fiber cells is
a useful model for studying the changes of the electrical properties
of gap junction (cell-to-cell) channels that are induced by an
alteration in connexin expression patterns. In this model, cuboidal
lens epithelial cells differentiate into elongated fiber cells, and
the expression of connexin43 (Cx43) in the epithelial cells is
replaced with the production of high levels of Cx50 and Cx46 in the
fiber cells. We now report a new procedure to isolate mouse lens
fiber cell pairs suitable for double whole cell patch clamp analysis.
Analysis was also performed for fiber-like cell pairs differentiated
from epithelial cells in culture. Voltage dependence and unitary
conductance of fiber cell gap junction channels were determined and
compared with the corresponding values previously measured for the
channels joining lens epithelial cells (8) and for lens connexin
channels formed in Xenopus oocyte pairs (38). Our results support a
differentiation induced shift towards stronger gap junctional voltage
dependence and larger unitary conductances in the fiber cells. Our
data further reflect a balanced functional contribution of Cx50 and
Cx46 in the fiber cell-to-cell channels rather than a predominance of
a single connexin.
Received 1 December 1994; accepted in final form 1 March 1995.
APS Manuscript Number C702-4.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 10 March 1995.