title: The lhx2 transcription factor controls thalamocortical axonal guidance by specific regulation of robo1 and robo2 receptors.
abstract: The assembly of neural circuits is dependent upon the generation of specific neuronal subtypes, each subtype displaying unique properties that direct the formation of selective connections with appropriate target cells. Actions of transcription factors in neural progenitors and postmitotic cells are key regulators in this process. LIM-homeodomain transcription factors control crucial aspects of neuronal differentiation, including subtype identity and axon guidance. Nonetheless, their regulation during development is poorly understood and the identity of the downstream molecular effectors of their activity remains largely unknown. Here, we demonstrate that the Lhx2 transcription factor is dynamically regulated in distinct pools of thalamic neurons during the development of thalamocortical connectivity in mice. Indeed, overexpression of Lhx2 provokes defective thalamocortical axon guidance in vivo, while specific conditional deletion of Lhx2 in the thalamus produces topographic defects that alter projections from the medial geniculate nucleus and from the caudal ventrobasal nucleus in particular. Moreover, we demonstrate that Lhx2 influences axon guidance and the topographical sorting of axons by regulating the expression of Robo1 and Robo2 guidance receptors, which are essential for these axons to establish correct connections in the cerebral cortex. Finally, augmenting Robo1 function restores normal axon guidance in Lhx2-overexpressing neurons. By regulating axon guidance receptors, such as Robo1 and Robo2, Lhx2 differentially regulates the axon guidance program of distinct populations of thalamic neurons, thus enabling the establishment of specific neural connections.
authors.affiliation: Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas and Universidad Miguel Hernández, 03550 Sant Joan d'Alacant, Spain.
authors.forename: Paula
authors.initials: P
authors.lastname: Marcos-Mondéjar
authors.forename: Sandra
authors.initials: S
authors.lastname: Peregrín
authors.forename: James Y
authors.initials: JY
authors.lastname: Li
authors.forename: Leif
authors.initials: L
authors.lastname: Carlsson
authors.forename: Shubha
authors.initials: S
authors.lastname: Tole
authors.forename: Guillermina
authors.initials: G
authors.lastname: López-Bendito
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology*; D002540:Cerebral Cortex / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D004622:Embryo, Mammalian; D017353:Gene Deletion; D018507:Gene Expression Regulation, Developmental; D060850:LIM-Homeodomain Proteins / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008813:Mice, Inbred ICR; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D009434:Neural Pathways / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D055495:Neurogenesis / Q000502:physiology*; D011971:Receptors, Immunologic / Q000096:biosynthesis*; D015398:Signal Transduction / Q000502:physiology; D013788:Thalamus / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*; D000097905:Roundabout Proteins
chemical_list: D060850:LIM-Homeodomain Proteins; D009419:Nerve Tissue Proteins; D011971:Receptors, Immunologic; D014157:Transcription Factors; D000097905:Roundabout Proteins; C489784:Lhx2 protein, mouse; C498888:Robo2 protein, mouse