Divergent mechanisms regulate conserved cardiopharyngeal development and gene expression in distantly related ascidians

作者：Stolfi Alberto; Lowe Elijah K; Racioppi Claudia; Ristoratore Filomena; Brown C Titus; Swalla Billie J; Christiaen Lionel^*

来源：eLife, 2014, 3.

DOI：10.7554/eLife.03728

• Development
• evolution
• ascidians
• tunicates
• Ciona
• Molgula
• DSD
• cardiopharyngeal mesoderm

Ascidians present a striking dichotomy between conserved phenotypes and divergent genomes: embryonic cell lineages and gene expression patterns are conserved between distantly related species. Much research has focused on Ciona or Halocynthia spp. but development in other ascidians remains poorly characterized. Here we surveyed the multipotent myogenic B7.5 lineage in Molgula spp. Comparisons to the homologous lineage in Ciona revealed identical cell division and fate specification events that result in segregation of larval, cardiac, and pharyngeal muscle progenitors. Moreover, the expression patterns of key regulators are conserved, but cross-species transgenic assays uncovered incompatibility, or "unintelligibility", of orthologous cis-regulatory sequences between Molgula and Ciona. These sequences drive identical expression patterns that are not recapitulated in cross-species assays. We show that this unintelligibility is likely due to changes in both cis- and trans-acting elements, hinting at widespread and frequent turnover of regulatory mechanisms underlying otherwise conserved aspects of ascidian embryogenesis.

• 出版日期2014-9-10