KCNQ1 and KCNE1 K+ channel components are involved in early left-right patterning in Xenopus laevis embryos.
Several ion transporters have been implicated in left-right (LR) patterning. Here, we characterize a new component of the early bioelectrical circuit: the potassium channel KCNQ1 and its accessory subunit KCNE1. Having cloned the native Xenopus versions of both genes, we show that both are asymmetrically localized as maternal proteins during the first few cleavages of frog embryo development in a process dependent on microtubule and actin organization. Molecular loss-of-function using dominant negative constructs demonstrates that both gene products are required for normal LR asymmetry. We propose a model whereby these channels provide an exit path for K(+) ions brought in by the H(+),K(+)-ATPase. This physiological module thus allows the obligate but electroneutral H(+),K(+)-ATPase to generate an asymmetric voltage gradient on the left and right sides. Our data reveal a new, bioelectrical component of the mechanisms patterning a large-scale axis in vertebrate embryogenesis.
Morokuma
Junji
J
Center for Regenerative and Developmental Biology, Forsyth Institute, Developmental Biology Department, Harvard School of Dental Medicine, Boston, MA 02115, USA.
Blackiston
Douglas
D
Levin
Michael
M
D000818:Animals; D019521:Body Patterning; D003001:Cloning, Molecular; D003599:Cytoskeleton / Q000378:metabolism; D004353:Drug Evaluation, Preclinical; D004625:Embryo, Nonmammalian / Q000196:embryology* / Q000378:metabolism*; D051657:KCNQ1 Potassium Channel / Q000235:genetics / Q000378:metabolism*; D008297:Male; D009928:Organ Specificity; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000196:embryology* / Q000378:metabolism*
C530745:KCNE1 protein, Xenopus; D051657:KCNQ1 Potassium Channel; D024642:Potassium Channels, Voltage-Gated; D029867:Xenopus Proteins