Fig. 3.

Developmental bioelectricity.

(A) Individual cells express ion channels and pumps in their membrane, which establish cell resting potentials. Voltage-sensitive fluorescent dyes can be used to view the spatio-temporal patterns of these potentials in vivo, such as the flank of a tadpole seen here (image provided by Douglas J. Blackiston). (B) Changes in voltage are transduced into second messenger cascades and downstream transcriptional responses by a variety of mechanisms including voltage-gated calcium channels, voltage-powered transporters of serotonin and butyrate, voltage-sensitive phosphatases, and electrophoresis through gap junctions. (C) Thus, activity of ion channels and pumps are transduced into changes of gene expression (which may include other ion channels, thus forming a feedback cycle). Spatial patterns of voltage and their signaling consequences serve as prepatterns for normal morphogenesis, such as the prepatterns of the tadpole face (D, reproduced from (Vandenberg et al., 2011)), or disease states such as tumors induced in tadpoles by expression of human oncogenes, detected by their bioelectric disruption (E) before they become morphologically obvious(F, close-up in G). Panel E-G reproduced with permission from (Chernet and Levin, 2013; Lobikin et al., 2012).