Role of the Sc C Terminus in Transcriptional Activation and E(spl) Repressor Recruitment

• Published in: The Journal of biological chemistry 2005-01, Vol.280 (2), p.1299-1305
• Main Authors: Giagtzoglou, Nikolaos, Koumbanakis, Konstantinos A., Fullard, John, Zarifi, Ioanna, Delidakis, Christos
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Animals, Genetically Modified; Basic Helix-Loop-Helix Transcription Factors; Binding Sites; Conserved Sequence; Dimerization; DNA-Binding Proteins - antagonists & inhibitors; DNA-Binding Proteins - chemistry; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Drosophila; Drosophila melanogaster - genetics; Drosophila Proteins - antagonists & inhibitors; Drosophila Proteins - chemistry; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Enhancer Elements, Genetic - genetics; Genes, Insect - genetics; Helix-Loop-Helix Motifs; Molecular Sequence Data; Protein Binding; Protein Structure, Quaternary; Protein Structure, Tertiary; Repressor Proteins - chemistry; Repressor Proteins - genetics; Repressor Proteins - metabolism; Transcription Factors - antagonists & inhibitors; Transcription Factors - chemistry; Transcription Factors - genetics; Transcription Factors - metabolism; Transcriptional Activation; Two-Hybrid System Techniques
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M408949200

Neurogenesis in all animals is triggered by the activity of a group of basic helix-loop-helix transcription factors, the proneural proteins, whose expression endows ectodermal regions with neural potential. The eventual commitment to a neural precursor fate involves the interplay of these proneural transcriptional activators with a number of other transcription factors that fine tune transcriptional responses at target genes. Most prominent among the factors antagonizing proneural protein activity are the HES basic helix-loop-helix proteins. We have previously shown (1) that two HES proteins of Drosophila, E(spl)mγ and E(spl)m7, interact with the proneural protein Sc and thereby get recruited onto Sc target genes to repress transcription. Using in vivo and in vitro assays we have now discovered an important dual role for the Sc C-terminal domain. On one hand it acts as a transcription activation domain, and on the other it is used to recruit E(spl) proteins. In vivo, the Sc C-terminal domain is required for E(spl) recruitment in an enhancer context-dependent fashion, suggesting that in some enhancers alternative interaction surfaces can be used to recruit E(spl) proteins.