PUBLICATION

Early, H+-V-ATPase-dependent proton flux is necessary for consistent left-right patterning of non-mammalian vertebrates

Authors
Adams, D.S., Robinson, K.R., Fukumoto, T., Yuan, S., Albertson, R.C., Yelick, P., Kuo, L., McSweeney, M., and Levin, M.
ID
ZDB-PUB-060327-4
Date
2006
Source
Development (Cambridge, England)   133(9): 1657-1671 (Journal)
Registered Authors
Albertson, R. Craig, Yelick, Pamela C., Yuan, Shipeng
Keywords
Left-right asymmetry, H+-V-ATPase, V-ATPase, Xenopus, Chick, Zebrafish, Axial patterning, Cytoplasmic pH, Membrane voltage
MeSH Terms
  • Actins/metabolism
  • Animals
  • Body Patterning*
  • Cell Membrane/metabolism
  • Chick Embryo
  • Embryo, Nonmammalian
  • Enzyme Inhibitors/pharmacology
  • Gene Expression Regulation, Developmental
  • H(+)-K(+)-Exchanging ATPase/chemistry*
  • H(+)-K(+)-Exchanging ATPase/metabolism*
  • Hydrogen-Ion Concentration
  • Immunohistochemistry
  • Models, Biological
  • Proton Pump Inhibitors
  • Protons*
  • Time Factors
  • Vertebrates/embryology*
  • Xenopus/embryology
  • Zebrafish/embryology
PubMed
16554361 Full text @ Development
Abstract
Biased left-right asymmetry is a fascinating and medically important phenomenon. We provide molecular genetic and physiological characterization of a novel, conserved, early, biophysical event that is crucial for correct asymmetry: H(+) flux. A pharmacological screen implicated the H(+)-pump H(+)-V-ATPase in Xenopus asymmetry, where it acts upstream of early asymmetric markers. Immunohistochemistry revealed an actin-dependent asymmetry of H(+)-V-ATPase subunits during the first three cleavages. H(+)-flux across plasma membranes is also asymmetric at the four- and eight-cell stages, and this asymmetry requires H(+)-V-ATPase activity. Abolishing the asymmetry in H(+) flux, using a dominant-negative subunit of the H(+)-V-ATPase or an ectopic H(+) pump, randomized embryonic situs without causing any other defects. To understand the mechanism of action of H(+)-V-ATPase, we isolated its two physiological functions, cytoplasmic pH and membrane voltage (Vmem) regulation. Varying either pH or Vmem, independently of direct manipulation of H(+)-V-ATPase, caused disruptions of normal asymmetry, suggesting roles for both functions. V-ATPase inhibition also abolished the normal early localization of serotonin, functionally linking these two early asymmetry pathways. The involvement of H(+)-V-ATPase in asymmetry is conserved to chick and zebrafish. Inhibition of the H(+)-V-ATPase induces heterotaxia in both species; in chick, H(+)-V-ATPase activity is upstream of Shh; in fish, it is upstream of Kupffer's vesicle and Spaw expression. Our data implicate H(+)-V-ATPase activity in patterning the LR axis of vertebrates and reveal mechanisms upstream and downstream of its activity. We propose a pH- and Vmem-dependent model of the early physiology of LR patterning.
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