Xenbase Image ID: 152491

Figure 7. Models for Involvement of H+/K+-ATPase in Early LR Asymmetry (A) Data presented here indicate that H+/K+-ATPase activity is localized to the right side of early Xenopus and chick embryos. An initiating mechanism to orient LR asymmetry has not been described experimentally in either chick or Xenopus but is envisaged to be responsible for the asymmetric H+/K+-ATPase activities, by localization of mRNA (Xenopus) or posttranslationally (chick), as described in the text. (B) H+/K+-ATPase function might directly regulate the secretion of an early determinant of asymmetric gene expression. (C) Alternatively, the H+/K+-ATPase might influence the propagation of unknown, low molecular weight LR determinants (green dots) between cells. Unidirectional propagation might rely simply on electrophoresis of charged determinants through open gap junction channels (depicted) or connexon gating (see text). The segregation of determinants triggers asymmetric expression of genes in multicellular fields. Image published in: Levin M et al. (2002) Copyright © 2002. Image reproduced with permission of the Publisher, Elsevier B. V. Larger Image Printer Friendly View

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