Transcriptome Analysis of Ciona intestinalis to Identify Genes Preferentially Expressed in the Larval Brain

The larval brain of Ciona intestinalis has similar architecture to that of vertebrates, but is only composed of approximately 330 cells. Transgenic embryos that carried Ci-beta-tubulin(promoter)::Kaede exhibited robust Kaede expression in the larval brain. Kaede-expressing cells were isolated, and their transcriptome was compared with that of cells that did not express Kaede using an oligonucleotide-based microarray. Our analysis identified 565 candidate genes that were preferentially expressed in the larval brain, 77 of which have previously been reported to be brain-related. The 565 genes included transcription factors, such as Otx, en, Pax3/7, Prop-A, Lhx1, Six3/6, Unc4-A, FoxC, and DMRT1; and signal transduction molecules, such as FGF4/5/6, Hedgehog1, Hedgehog2, patched, Fringe1, and Dkk3. Nearly 30 of the identified genes coded for receptors for neurotransmitters, neuropeptides or hormone pepetides. In addition, 15 genes encoded neuropeptides and hormone peptides, five of which were novel. Our catalog of genes that are expressed in the Ciona larval brain provides a foundation for future studies exploring the complex gene regulatory networks that mediate chordate brain development and function. Two samples (Brain vs Cells without Brain),Two biological replicates,Dye Swap design