title: Characterization of the Rx1-dependent transcriptome during early retinal development.
abstract: BACKGROUND
  The transcription factor Rx1, also known as Rax, controls key properties of retinal precursors including migration behavior, proliferation, and maintenance of multipotency. However, Rx1 effector genes are largely unknown.
  
  
  RESULTS
  To identify genes controlled by Rx1 in early retinal precursors, we compared the transcriptome of Xenopus embryos overexpressing Rx1 to that of embryos in which Rx1 was knocked-down. In particular, we selected 52 genes coherently regulated, i.e., actived in Rx1 gain of function and repressed in Rx1 loss of function experiments, or vice versa. RT-qPCR and in situ hybridization confirmed the trend of regulation predicted by microarray data for the selected genes. Most of the genes upregulated by Rx1 are coexpressed with this transcription factor, while downregulated genes are either not expressed or expressed at very low levels in the early developing retina. Putative direct Rx1 target genes, activated by GR-Rx1 in the absence of protein synthesis, include Ephrin B1 and Sh2d3c, an interactor of ephrinB1 receptor, which represent candidate novel effectors for the migration promoting activity of Rx1.
  
  
  CONCLUSIONS
  This study identifies previously undescribed Rx1 regulated genes mainly involved in transcription regulation, cell migration/adhesion, and cell proliferation that contribute to delineate the molecular mechanisms underlying Rx1 activities.
authors.affiliation: Unità di Biologia Cellulare e dello Sviluppo, Dipartimento di Biologia, Università di Pisa, Pisa, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Giudetti
authors.forename: Martina
authors.initials: M
authors.lastname: Giannaccini
authors.forename: Daniele
authors.initials: D
authors.lastname: Biasci
authors.forename: Sara
authors.initials: S
authors.lastname: Mariotti
authors.forename: Andrea
authors.initials: A
authors.lastname: Degl'innocenti
authors.forename: Michele
authors.initials: M
authors.lastname: Perrotta
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Barsacchi
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Andreazzoli
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D002454:Cell Differentiation / Q000235:genetics; D004625:Embryo, Nonmammalian; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D046228:Microarray Analysis; D012160:Retina / Q000196:embryology* / Q000378:metabolism; D059467:Transcriptome; D014981:Xenopus / Q000196:embryology / Q000235:genetics; D029867:Xenopus Proteins / Q000502:physiology*; D014982:Xenopus laevis / Q000196:embryology / Q000235:genetics
chemical_list: D005136:Eye Proteins; C524416:Rax protein, Xenopus; D029867:Xenopus Proteins
keywords: Rax; Xenopus; cell migration; microarray; proliferation; retinal progenitors