• Spray, David C. (PI)
  • White, R.O.Y. (PI)
  • Saez, Juan (PI)
  • Hall, Linda (PI)
  • Ginzberg, Rosemary (PI)
  • Kessler, John (PI)
  • Bargiello, Thaddeus (PI)
  • Bennett, Michael V. L. (PI)
  • Hertzberg, Elliot (PI)
  • Verselis, Vyto (PI)
  • White, R.O.Y. (PI)
  • Hertzberg, Elliot (PI)
  • Verselis, Vyto (PI)

Project: Research project

Project Details


Gap junctions provide aqueous channels between cells which are permeable to
ions and small molecules. These junctions transmit impulses between
excitable cells, but are common in many inexcitable tissues where their
role is ill defined. In the latter, they may transmit signalling molecules
and mediate sharing of metabolites. Gap junction proteins, now termed
connexins, have been shown to comprise a family of several members encoded
by distinct, but homologous genes. Specific nucleotide probes and
antibodies are allowing classification of which connexin is expressed by
which cell, and permit analysis of regulation at the levels of
transcription, translation and degradation. Gating of single gap junction
channels can be detected in appropriate cells. This Program Project, an
extension of our previous Program, will use these new probes and techniques
to study gap junctions in respect to connexin type, gating, regulation and
function. Project 1 Physiological Properties and Regulation of Gap
Junctions in Non-neuronal Cells will utilize several tissues in which these
questions have been little studied. Preliminary data suggest functionally
significant modulation. Project 2 Gap Junctions In the Nervous System will
study neurons and glia in culture, in particular under conditions in which
gap junctions are regulated by hormones and trophic factors. Regional
differences and specificity of junction formation are major foci. Project 3
Exogenous of Expression of Gap Junction Proteins will utilize exogenous
mRNAs, naturally occurring and modified, for expression in Xenopus oocytes
and transfection into cell lines. How molecular modification changes
junctional properties is a major focus as is alteration in cell behavior by
specifically introducing or blocking expression of gap junctions. A third
facet will be introduction of normal or modified proteins into artificial
bilayers for study of single channel properties. Project 4 Pinealocyte Gap
Junctions: Characterization, Regulation and Function extends to these cells
the same techniques as applied in Projects I and 2. Pinealocytes uniquely
express a particular connexin in isolation, and although they are
neurosecretory, they appear not to employ exocytosis; thus the role of
their gap junctions in secretion may be unusual. Project 5 Classical and
Molecular Genetic Approach to Gap Junctions will develop antibody probes
for gap junctions in Drosophila and C. elegans as tools in subsequent
analysis. These gap junctions, often inaccessible in situ, will be studied
by incorporation into planar bilayers or by expression in Xenopus oocytes.
New strategies are proposed for isolating gap junction genes. Core A
Administrative provides vital research services. Core B Cytological
provides an essential morphological link between electrophysiological
measurements of coupling and biochemical determination of protein levels.
Immunocytochemistry with LM resolution often can quantify incidence of gap
junctions, and gap junction antigen can be localized with EM resolution.
Effective start/end date12/31/896/30/00


  • Genetics
  • Physiology
  • Medicine(all)
  • Neuroscience(all)