title: Dual role of Tlx3 as modulator of Prrxl1 transcription and phosphorylation.
abstract: The proper establishment of the dorsal root ganglion/spinal cord nociceptive circuitry depends on a group of homeodomain transcription factors that includes Prrxl1, Brn3a and Tlx3. By the use of epistatic analysis, it was suggested that Tlx3 and Brn3a, which highly co-localize with Prrxl1 in these tissues, are required to maintain Prrxl1 expression. Here, we report two Tlx3-dependent transcriptional mechanisms acting on Prrxl1 alternative promoters, referred to as P3 and P1/P2 promoters. We demonstrate that (i) Tlx3 induces the transcriptional activity of the TATA-containing promoter P3 by directly binding to a bipartite DNA motif and (ii) it synergistically interacts with Prrxl1 by indirectly activating the Prrxl1 TATA-less promoters P1/P2 via the action of Brn3a. The Tlx3 N-terminal domain 1-38 was shown to have a major role on the overall Tlx3 transcriptional activity and the C-terminus domain (amino acids 256-291) to mediate the Tlx3 effect on promoters P1/P2. On the other hand, the 76-111 domain was shown to decrease Tlx3 activity on the TATA-promoter P3. In addition to its action on Prrxl1 alternative promoters, Tlx3 proved to have the ability to induce Prrxl1 phosphorylation. The Tlx3 domain responsible for Prrxl1 hyperphosphorylation was mapped and encompasses amino acid residues 76 to 111. Altogether, our results suggest that Tlx3 uses distinct mechanisms to tightly modulate Prrxl1 activity, either by controlling its transcriptional levels or by increasing Prrxl1 phosphorylation state.
authors.affiliation: Departamento de Biologia Experimental, Faculdade de Medicina, Universidade do Porto Porto, 4200-319, Portugal; Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto 4150, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Regadas
authors.affiliation: Departamento de Biologia Experimental, Faculdade de Medicina, Universidade do Porto Porto, 4200-319, Portugal; Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto 4150, Portugal; Centro Hospitalar de São João, Porto 4200-319, Portugal.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Soares-Dos-Reis
authors.affiliation: Departamento de Biologia Experimental, Faculdade de Medicina, Universidade do Porto Porto, 4200-319, Portugal; Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto 4150, Portugal.
authors.forename: Miguel
authors.initials: M
authors.lastname: Falcão
authors.affiliation: Departamento de Biologia Experimental, Faculdade de Medicina, Universidade do Porto Porto, 4200-319, Portugal; Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto 4150, Portugal.
authors.forename: Mariana Raimundo
authors.initials: MR
authors.lastname: Matos
authors.affiliation: Departamento de Biologia Experimental, Faculdade de Medicina, Universidade do Porto Porto, 4200-319, Portugal; Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto 4150, Portugal.
authors.forename: Filipe Almeida
authors.initials: FA
authors.lastname: Monteiro
authors.affiliation: Departamento de Biologia Experimental, Faculdade de Medicina, Universidade do Porto Porto, 4200-319, Portugal; Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto 4150, Portugal.
authors.forename: Deolinda
authors.initials: D
authors.lastname: Lima
authors.affiliation: Departamento de Biologia Experimental, Faculdade de Medicina, Universidade do Porto Porto, 4200-319, Portugal; Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto 4150, Portugal. Electronic address: cregueng@med.up.pt.
authors.forename: Carlos
authors.initials: C
authors.lastname: Reguenga
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D004622:Embryo, Mammalian; D018507:Gene Expression Regulation, Developmental; D006367:HeLa Cells; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism*; D059225:Nociception; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D013116:Spinal Cord / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*
chemical_list: D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; C433766:Prrxl1 protein, mouse; C487377:Tlx3 protein, mouse; D014157:Transcription Factors
keywords: Alternative promoters; Brn3a; Nociception; Phosphorylation; Prrxl1; Tlx3