title: Functional characterization of a minimal sequence essential for the expression of human TLX2 gene.
abstract: TLX2 is an orphan homeodomain transcription factor whose expression is mainly associated with tissues derived from neural crest cells. Recently, we have demonstrated that PHOX2A and PHOX2B are able to enhance the neural cell-type specific expression of human TLX2 by binding distally the 5'-flanking region. In the present work, to deepen into the TLX2 transcription regulation, we have focused on the proximal 5'- flanking region of the gene, mapping the transcription start site and identifying a minimal promoter necessary and sufficient for the basal transcription in cell lines from different origin. Site-directed mutagenesis has allowed to demonstrate that the integrity of this sequence is crucial for gene expression, while electrophoretic mobility shift assays and chromatin immunoprecipitation experiments have revealed that such an activity is dependent on the binding of a PBX factor. Consistent with these findings, such a basal promoter activity has resulted to be enhanced by the previously reported PHOX2-responding sequence.
authors.affiliation: Laboratorio di Genetica Molecolare, Istituto G Gaslini Universita di Genova, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Borghini
authors.forename: Tiziana
authors.initials: T
authors.lastname: Bachetti
authors.forename: Monica
authors.initials: M
authors.lastname: Fava
authors.forename: Marco Di
authors.initials: MD
authors.lastname: Duca
authors.forename: Roberto
authors.initials: R
authors.lastname: Ravazzolo
authors.forename: Isabella
authors.initials: I
authors.lastname: Ceccherini
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D005786:Gene Expression Regulation / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D009432:Neural Crest / Q000166:cytology / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics; D015533:Transcriptional Activation / Q000235:genetics; D014407:Tumor Cells, Cultured
chemical_list: D018398:Homeodomain Proteins; C491534:TLX2 protein, human