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Monteiro FA, Miranda RM, Samina MC, Dias AF, Raposo AASF, Oliveira P, Reguenga C, Castro DS, Lima D. Tlx3 Exerts Direct Control in Specifying Excitatory Over Inhibitory Neurons in the Dorsal Spinal Cord. Front Cell Dev Biol 2021; 9:642697. [PMID: 33996801 PMCID: PMC8117147 DOI: 10.3389/fcell.2021.642697] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 03/30/2021] [Indexed: 11/28/2022] Open
Abstract
The spinal cord dorsal horn is a major station for integration and relay of somatosensory information and comprises both excitatory and inhibitory neuronal populations. The homeobox gene Tlx3 acts as a selector gene to control the development of late-born excitatory (dILB) neurons by specifying glutamatergic transmitter fate in dorsal spinal cord. However, since Tlx3 direct transcriptional targets remain largely unknown, it remains to be uncovered how Tlx3 functions to promote excitatory cell fate. Here we combined a genomics approach based on chromatin immunoprecipitation followed by next generation sequencing (ChIP-seq) and expression profiling, with validation experiments in Tlx3 null embryos, to characterize the transcriptional program of Tlx3 in mouse embryonic dorsal spinal cord. We found most dILB neuron specific genes previously identified to be directly activated by Tlx3. Surprisingly, we found Tlx3 also directly represses many genes associated with the alternative inhibitory dILA neuronal fate. In both cases, direct targets include transcription factors and terminal differentiation genes, showing that Tlx3 directly controls cell identity at distinct levels. Our findings provide a molecular frame for the master regulatory role of Tlx3 in developing glutamatergic dILB neurons. In addition, they suggest a novel function for Tlx3 as direct repressor of GABAergic dILA identity, pointing to how generation of the two alternative cell fates being tightly coupled.
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Affiliation(s)
- Filipe A Monteiro
- Unidade de Biologia Experimental, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,Pain Research Group, Instituto de Biologia Molecular e Celular, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Rafael M Miranda
- Unidade de Biologia Experimental, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,Pain Research Group, Instituto de Biologia Molecular e Celular, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Marta C Samina
- Unidade de Biologia Experimental, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,Pain Research Group, Instituto de Biologia Molecular e Celular, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Ana F Dias
- Pain Research Group, Instituto de Biologia Molecular e Celular, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Alexandre A S F Raposo
- Molecular Neurobiology Group, Instituto Gulbenkian de Ciência, Oeiras, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisboa, Portugal
| | - Patrícia Oliveira
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Diagnostics, Institute of Molecular Pathology and Immunology, University of Porto, Porto, Portugal
| | - Carlos Reguenga
- Unidade de Biologia Experimental, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,Pain Research Group, Instituto de Biologia Molecular e Celular, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Diogo S Castro
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Molecular Neurobiology Group, Instituto Gulbenkian de Ciência, Oeiras, Portugal.,Stem Cells & Neurogenesis Group, Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Deolinda Lima
- Unidade de Biologia Experimental, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,Pain Research Group, Instituto de Biologia Molecular e Celular, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
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A role for prolyl isomerase PIN1 in the phosphorylation-dependent modulation of PRRXL1 function. Biochem J 2017; 474:683-697. [PMID: 28049756 DOI: 10.1042/bcj20160560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 12/10/2016] [Accepted: 01/03/2017] [Indexed: 11/17/2022]
Abstract
Prrxl1 encodes for a paired-like homeodomain transcription factor essential for the correct establishment of the dorsal root ganglion - spinal cord nociceptive circuitry during development. Prrxl1-null mice display gross anatomical disruption of this circuitry, which translates to a markedly diminished sensitivity to noxious stimuli. Here, by the use of an immunoprecipitation and mass spectrometry approach, we identify five highly conserved phosphorylation sites (T110, S119, S231, S233 and S251) in PRRXL1 primary structure. Four are phospho-S/T-P sites, which suggest a role for the prolyl isomerase PIN1 in regulating PRRXL1. Accordingly, PRRXL1 physically interacts with PIN1 and displays diminished transcriptional activity in a Pin1-null cell line. Additionally, these S/T-P sites seem to be important for PRRXL1 conformation, and their point mutation to alanine or aspartate down-regulates PRRXL1 transcriptional activity. Altogether, our findings provide evidence for a putative novel role of PIN1 in the development of the nociceptive system and indicate phosphorylation-mediated conformational changes as a mechanism for regulating the PRRXL1 role in the process.
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The transcription factor TCF-1 initiates the differentiation of T(FH) cells during acute viral infection. Nat Immunol 2015. [PMID: 26214740 DOI: 10.1038/ni.3229] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Induction of the transcriptional repressor Bcl-6 in CD4(+) T cells is critical for the differentiation of follicular helper T cells (T(FH) cells), which are essential for B cell-mediated immunity. In contrast, the transcription factor Blimp1 (encoded by Prdm1) inhibits T(FH) differentiation by antagonizing Bcl-6. Here we found that the transcription factor TCF-1 was essential for both the initiation of T(FH) differentiation and the effector function of differentiated T(FH) cells during acute viral infection. Mechanistically, TCF-1 bound directly to the Bcl6 promoter and Prdm1 5' regulatory regions, which promoted Bcl-6 expression but repressed Blimp1 expression. TCF-1-null T(FH) cells upregulated genes associated with non-T(FH) cell lineages. Thus, TCF-1 functions as an important hub upstream of the Bcl-6-Blimp1 axis to initiate and secure the differentiation of T(FH) cells during acute viral infection.
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