Biology
Center for Developmental and Regenerative Biology
Tufts University (Medford, MA)
While laterality is a crucial aspect of embryonic development, many key questions remain about the mechanisms embryos use to reliably distinguish left from right. Understanding this will illuminate fascinating problems of evolutionary, cell, and developmental biology, as well as an important class of birth defects. In mammals, the left-right (LR) axis is thought to be established during gastrulation. However, in frog, chick, zebrafish, and invertebrates, this occurs earlier. In Xenopus, right-sided intracellular localization of four ion transporters at the first cleavages determine asymmetry of the embryo, since the large early blastomeres allow physiological asymmetries across the first cleavage plane to be imposed across the whole embryo’s midline. However, data indicate that correct laterality may also be imposed by an organizer induced at the 1000-cell stage, implying a different mechanism. In order to unify the understanding of asymmetry among phyla, we will determine: (1) can Xenopus properly orient the LR axis in embryos at a stage when no single cell’s intracellular localization can distribute signals across the embryo’s midline? (2) how do the early blastomeres utilize cytoskeletal chirality and transport machinery to achieve consistent asymmetry? These aims will result in revisions of current models of LR patterning among vertebrates.


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Vandenberg LN, Soto AM, and Sonnenschein C
Vandenberg LN, Maffini MV, Schaeberle CM, Rubin BS, Sonnenschein C, and Soto AM.
Vandenberg LN, Sonnenschein C, and Soto AM.
Vandenberg LN, Maffini MV, Wadia PR, Sonnenschein C, Rubin BS, and Soto AM.
Wadia PR, Vandenberg LN, Schaeberle CM, Rubin BS, Sonnenschein C, and Soto AM.
LN Vandenberg, PR Wadia, MV Maffini, C Sonnenschein, and AM Soto.
Vandenberg LN, Maffini MV, Wadia PR, Sonnenschein C, Rubin BS, and Soto AM