Early embryonic expression of ion channels and pumps in chick and Xenopus development

Abstract

An extensive body of literature implicates endogenous ion currents and standing voltage potential differences in the control of events during embryonic morphogenesis. Although the expression of ion channel and pump genes, which are responsible for ion flux, has been investigated in detail in nervous tissues, little data are available on the distribution and function of specific channels and pumps in early embryogenesis. To provide a necessary basis for the molecular understanding of the role of ion flux in development, we surveyed the expression of ion channel and pump mRNAs, as well as other genes that help to regulate membrane potential. Analysis in two species, chick and Xenopus, shows that several ion channel and pump mRNAs are present in specific and dynamic expression patterns in early embryos, well before the appearance of neurons. Examination of the distribution of maternal mRNAs reveals complex spatiotemporal subcellular localization patterns of transcripts in early blastomeres in Xenopus. Taken together, these data are consistent with an important role for ion flux in early embryonic morphogenesis; this survey characterizes candidate genes and provides information on likely embryonic contexts for their function, setting the stage for functional studies of the morphogenetic roles of ion transport.

ADrosophilaKCNQ Channel Essential for Early Embryonic Development

“…Does the essential role of dKCNQ for early embryonic development require its channel activity? Ionic flow and resting membrane potential have been implicated in the regulation of embryonic morphogenesis, best studied in chick and Xenopus (Rutenberg et al, 2002). Consistent with this idea, several ion channel and ion pump mRNAs are present in specific and dynamic expression patterns in early embryos in both species, well before neuralization.…”

Embryonic and larval expression of zebrafish voltage‐gated sodium channel α‐subunit genes

“…Previous studies examining the roles of ion channels during early embryonic development have focused largely on voltage-gated calcium channels (but see Rutenberg et al, 2002). However, in addition to calcium channels, voltagegated sodium channels (Na v 1) initiate electrical signals.…”

Fusicoccin signaling reveals 14-3-3 protein function as a novel step in left-right patterning during amphibian embryogenesis

“…In particular, H + flux and the resulting pH gradients are known to be crucial in embryonic development and neoplastic progression (Perona and Serrano, 1988;Grandin and Charbonneau, 1989;Martinez-Zaguilan and Gillies, 1992;Uzman et al, 1998;Levin et al, 2002). As part of our effort to understand the contribution of endogenous ion flows and gradients to patterning Rutenberg et al, 2002;Levin et al, 2002), we have begun to characterize signaling pathways that control proton flux across cell membranes.…”