RRC ID 28126
著者 Ikeda T, Matsuoka T, Satou Y.
タイトル A time delay gene circuit is required for palp formation in the ascidian embryo.
ジャーナル Development
Abstract The ascidian larval brain and palps (a putative rudimentary placode) are specified by two transcription factor genes, ZicL and FoxC, respectively. FGF9/16/20 induces ZicL expression soon after the bi-potential ancestral cells divide into the brain and palp precursors at the early gastrula stage. FGF9/16/20 begins to be expressed at the 16-cell stage, and induces several target genes, including Otx, before the gastrula stage. Here, we show that ZicL expression in the brain lineage is transcriptionally repressed by Hes-a and two Blimp-1-like zinc finger proteins, BZ1 and BZ2, in the bi-potential ancestral cells. ZicL is precociously expressed in the bi-potential cells in embryos in which these repressors are knocked down. This precocious ZicL expression produces extra brain cells at the expense of palp cells. The expression of BZ1 and BZ2 is turned off by a negative auto-feedback loop. This auto-repression acts as a delay circuit that prevents ZicL from being expressed precociously before the brain and palp fates split, thereby making room within the neural plate for the palps to be specified. Addition of the BZ1/2 delay timer circuit to the gene regulatory network responsible for brain formation might represent a key event in the acquisition of the primitive palps/placodes in an ancestral animal.
巻・号 140(23)
ページ 4703-8
公開日 2013-12
DOI 10.1242/dev.100339
PII 140/23/4703
PMID 24255097
MeSH Animals Brain / embryology* Brain / metabolism* Cell Cycle Cell Differentiation / genetics Ciona intestinalis / embryology* Ciona intestinalis / genetics Ciona intestinalis / metabolism Embryo, Nonmammalian / metabolism Gene Expression Regulation, Developmental Gene Knockdown Techniques Signal Transduction Transcription Factors / biosynthesis Transcription Factors / genetics Transcription Factors / metabolism* Zinc Fingers / genetics*
IF 5.843
引用数 11
カタユウレイボヤ・(ニッポンウミシダ) Wild C. int