Left-right asymmetric heart jogging increases the robustness of dextral heart looping in zebrafish.

Left-right asymmetric heart jogging increases the robustness of dextral heart looping in zebrafish. Dev Biol. 2019 Nov 20;: Authors: Grimes DT, Patterson VL, Luna-Arvizu G, Schottenfeld-Roames J, Irons ZH, Burdine RD Abstract Building a left-right (L-R) asymmetric organ requires asymmetric information. This comes from various sources, including asymmetries in embryo-scale genetic cascades, organ-intrinsic mechanical forces, and cell-level chirality, but the relative influence of these sources and how they collaborate to drive asymmetric morphogenesis is not understood. During zebrafish heart development, the linear heart tube extends to the left of the midline in a process known as jogging. The jogged heart then undergoes dextral (i.e. rightward) looping to correctly position the heart chambers relative to one another. Left lateralized jogging is governed by the left-sided expression of Nodal in mesoderm tissue, while looping laterality is mainly controlled by heart-intrinsic cell-level asymmetries in the actomyosin cytoskeleton. The purpose of lateralized jogging is not known. Moreover, after jogging, the heart tube returns to a midline position and so it is not clear whether or how jogging may impact the dextral loop. Here, we characterize a novel loss-of-function mutant in the zebrafish Nodal homolog southpaw (spaw) that appears to be a true null. We then assess the relationship between jogging and looping laterality in embryos la...
Source: Developmental Biology - Category: Biology Authors: Tags: Dev Biol Source Type: research
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