Figure 3.

Perturbation of growth in Xenopus embryos caused by manipulation of ion channels and electroporation. A variety of mRNAs encoding wild-type and mutant channels were microinjected into frog embryo blastomeres to screen for bioelectrical signals with roles in growth and pattern control. The VSOP¹⁶⁷ proton channel (kindly provided by Yasushi Okamura) (A), the Cx32 gap junction subunit (plasmid kindly provided by Dan Goodenough) (B and C), and the HERG K⁺ channel (plasmid kindly provided by Annarosa Arcangeli) (D) result in ectopic growth and abnormal duplication of body structures such as eyes, sometimes forming extensive fin-like protrusions that are clearly associated with increases in cell growth. (E–E”’) Electroporation of embryos at stage 33, with no DNA, (95 msec interval, 5 msec pulse, 10X repeated) results in significant areas of ectopic growth 24 hours later. Red arrows indicate hyperproliferation.