TY - JOUR TI - Characterization of convergent thickening, a major convergence force producing morphogenic movement in amphibians AU - Shook, David R AU - Wen, Jason WH AU - Rolo, Ana AU - O'Hanlon, Michael AU - Francica, Brian AU - Dobbins, Destiny AU - Skoglund, Paul AU - DeSimone, Douglas W AU - Winklbauer, Rudolf AU - Keller, Ray E A2 - Solnica-Krezel, Lilianna A2 - Bronner, Marianne E A2 - Solnica-Krezel, Lilianna A2 - Munro, Ed VL - 11 PY - 2022 DA - 2022/04/11 SP - e57642 C1 - eLife 2022;11:e57642 DO - 10.7554/eLife.57642 UR - https://doi.org/10.7554/eLife.57642 AB - The morphogenic process of convergent thickening (CT) was originally described as the mediolateral convergence and radial thickening of the explanted ventral involuting marginal zone (IMZ) of Xenopus gastrulae (Keller and Danilchik, 1988). Here, we show that CT is expressed in all sectors of the pre-involution IMZ, which transitions to expressing convergent extension (CE) after involution. CT occurs without CE and drives symmetric blastopore closure in ventralized embryos. Assays of tissue affinity and tissue surface tension measurements suggest CT is driven by increased interfacial tension between the deep IMZ and the overlying epithelium. The resulting minimization of deep IMZ surface area drives a tendency to shorten the mediolateral (circumblastoporal) aspect of the IMZ, thereby generating tensile force contributing to blastopore closure (Shook et al., 2018). These results establish CT as an independent force-generating process of evolutionary significance and provide the first clear example of an oriented, tensile force generated by an isotropic, Holtfreterian/Steinbergian tissue affinity change. KW - morphogenesis KW - blastopore closure KW - biomechanics KW - gastrulation KW - convergent thickening KW - tissue surface tension JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -