Expression patterns of innexins functioning in <i>C. elegans</i> body-wall muscle.

<p>Expression patterns were assessed by analyzing GFP signal in live worms expressing innexin promoter and GFP transcriptional fusions. Body-wall muscle expression (indicated by arrows) was observed for four of the six innexins important to muscle electrical coupling, including <i>unc-9, inx-10, inx-11</i> and <i>inx-18</i>. The <i>unc-9</i> expression data were shown previously [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0076877#B33" target="_blank">33</a>,<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0076877#B34" target="_blank">34</a>].</p

Junctional conductance (<i>G</i>_<i>j</i>) of <i>C. elegans</i> body-wall muscle was significantly decreased in mutants of six innexins.

<p><b>A</b>. Diagram showing ventral body-wall muscle cells. Ventral muscles include the left and right quadrants with each quadrant consisting of two rows of muscle cells in a monolayer. The highlighted cell pairs (L1/L2 and R1/R2) represent those used for electrophysiological analyses. <b>B</b>. <i>G</i>_<i>j</i> was indistinguishable between wild type (WT) and mutants of 16 innexins. <b>C</b>. Mutants of 6 innexins showed significantly lower <i>G</i>_<i>j</i> when compared with WT, and the coupling defect was rescued completely by expressing a wild-type innexin in each corresponding mutant. The asterisk (*) indicates a statistically significant difference compared with WT. The number on each bar represents the number (<i>N</i>) of cell pairs analyzed.</p

Speculative models of muscle gap junctions.

<p>These highly speculative models are used to illustrate three possible stoichiometries out of the myriad possibilities. See the text for reasons for speculating these models.</p