Activation of a T-box-Otx2-Gsc gene network independent of TBP and TBP-related factors.
Embryonic development relies on activating and repressing regulatory influences that are faithfully integrated at the core promoter of individual genes. In vertebrates, the basal machinery recognizing the core promoter includes TATA-binding protein (TBP) and two TBP-related factors. In Xenopus embryos, the three TBP family factors are all essential for development and are required for expression of distinct subsets of genes. Here, we report on a non-canonical TBP family-insensitive (TFI) mechanism of transcription initiation that involves mesoderm and organizer gene expression. Using TBP family single- and triple-knockdown experiments, α-amanitin treatment, transcriptome profiling and chromatin immunoprecipitation, we found that TFI gene expression cannot be explained by functional redundancy, is supported by active transcription and shows normal recruitment of the initiating form of RNA polymerase II to the promoter. Strikingly, recruitment of Gcn5 (also known as Kat2a), a co-activator that has been implicated in transcription initiation, to TFI gene promoters is increased upon depletion of TBP family factors. TFI genes are part of a densely connected TBP family-insensitive T-box-Otx2-Gsc interaction network. The results indicate that this network of genes bound by Vegt, Eomes, Otx2 and Gsc utilizes a novel, flexible and non-canonical mechanism of transcription that does not require TBP or TBP-related factors.
['Gazdag|Emese|E|', 'Jacobi|Ulrike G|UG|', 'van Kruijsbergen|Ila|I|', 'Weeks|Daniel L|DL|', 'Veenstra|Gert Jan C|GJ|http://orcid.org/0000-0002-7787-4940']
D000818:Animals D054262:Gastrulation D018507:Gene Expression Regulation, Developmental D055785:Gene Knockdown Techniques D053263:Gene Regulatory Networks D051956:Goosecoid Protein D051548:Histone Acetyltransferases D051857:Otx Transcription Factors D011485:Protein Binding D035182:TATA Box Binding Protein-Like Proteins D035181:TATA-Box Binding Protein D061785:Transcription Initiation, Genetic D014981:Xenopus D029867:Xenopus Proteins
TATA-binding protein Xenopus Mesoderm Organizer Gene regulation