Volume 17, Number 13,
Issue of July 1, 1997
pp. 5108-5118
Copyright ©1997 Society for Neuroscience
Diverse Expression and Distribution of Shaker
Potassium Channels during the Development of the Drosophila
Nervous System
Received July 8, 1996; revised March 28, 1997; accepted April 10, 1997.
Oscar Rogero,
Barbara Hämmerle, and
Francisco J. Tejedor
Instituto de Neurociencias, Instituto Cajal, Consejo Superior de
Investigaciones Cientificas, Universidad de Alicante, San Juan,
03080 Alicante, Spain
The spatio-temporal expression of Shaker
(Sh) potassium channels (Kch) in the developing and
adult nervous system of Drosophila has been studied at
the molecular and histological level using specific antisera.
Sh Kch are distributed in most regions of the nervous
system, but their expression is restricted to only certain populations
of cells. Sh Kch have been found in the following three
locations: in synaptic areas of neuropile, in axonal fiber tracks, and
in a small number of neuronal cell bodies. This wide subcellular
localization, together with a diverse distribution, implicates
Sh Kch in multiple neuronal functions.
Experiments performed with Sh mutants that specifically
eliminate a few of the Sh Kch splice variants clearly
demonstrate an abundant differential expression and usage of the wide
repertoire of Sh isoforms, but they do not support the
idea of extensive segregation of these isoforms among different
populations of neurons. Sh Kch are predominantly
expressed at late stages of postembryonic development and adulthood.
Strikingly, wide changes in the repertoire of Sh splice
isoforms occur some time after the architecture of the nervous system
is complete, indicating that the expression of Sh Kch
contributes to the final refinements of neuronal differentiation. These
late changes in the expression and distribution of Sh
Kch seem to correlate with activity patterns suggesting that
Sh Kch may be involved in adaptative mechanisms of
excitability.
Key words:
potassium channels;
Shaker;
Drosophila;
K-channel expression;
K-channel localization;
K-channel distribution