Primodium disorganisation and absence of rosette formation.

Abstract

<p><b>A′.</b> Schematic representation of a normal <i>claudinB-GFP</i> embryo at 30 hpf and detailed organization of the primordium with rosette structure. Red spot indicates a normal concentration point of actin. <b>A, B.</b> Phalloidin staining (Phalloidin-TRITC) in control embryo <i>claudinB-GFP</i>, at 30 hpf, is observed in muscle cells and within the primodium at the center of the rosette (arrows), on the apical side. <b>C, D.</b> Phalloidin-TRITC staining in <i>PrP2</i>-MO, no rosette structure is observed and no actin concentration is found. <b>E, F.</b> Higher magnification shows the co-localization of central actin concentration with <i>claudinB-GFP</i> at the rosette center in control. In morphants, cell disorganization is observed and no actin concentration is observed associated with the absence of a rosette. <b>G–I.</b> Phalloidin staining and DAPI nuclei labeling highlight the primordium and rosette center (arrows) in control embryos. <b>J–L.</b> In <i>PrP2^−/−</i> mutants, actin apical localization in rosette was severely reduced or barely detectable (arrow) and primordium organization at the periphery was impaired: loose cells were visible on the border (arrowheads). <b>I′, L′.</b> In <i>PrP2^−/−</i> mutant, the primordium position was often delayed and the first neuromast deposited close to the ear. <b>M</b>. Quantification of rosette number was established in control (n = 20), <i>PrP2</i>-MO (n = 84) and <i>PrP2^−/−</i> mutant (n = 28) using actin staining at the center, **: p<0.01, ***: p<0.001, Student t test. See also associated <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0113331#pone.0113331.s002" target="_blank">Movies S1</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0113331#pone.0113331.s006" target="_blank">S5</a>.</p