Expression profiling of Ciona intestinalis neurula and mid-tailbud stage embryos expressing altered forms of the transcription factor Ci-Tbx2/3 in the notochord. Ciona intestinalis

Despite being found in the notochord of several chordates, the roles of the Tbx2 subfamily of T-box transcription factors in the development of this tissue remain largely unknown. We explored the targets of the only Tbx2 subfamily member in Ciona intestinalis, Ci-Tbx2/3, by expressing mutant forms of the transcriptional regulator using the Ci-Bra promoter region. We produced a dominant interfering version of Ci-Tbx2/3 (Tbx2/3DBD) through expression of a truncated version consisting only of its DNA-binding domain (DBD) and a constitutive activator form by attaching the T-box of Ci-Tbx2/3 to the VP16 transactivation domain (Tbx2/3VP16). These constructs were introduced into 1-cell stage embryos and grown to the neurula (N) or mid-tailbud (mTb) stage to capture targets regulated throughout notochord morphogenesis. Overall design: Ci-Tbx2/3 targets were ascertained using whole-genome custom Affymetrix microarrays to compare the transcription levels of Tbx2/3DBD and Tbx2/3VP16 expressing embryos to wild-type controls (Bra>GFP) at the neurula or mTb stages.