title: OTX2 loss causes rod differentiation defect in CRX-associated congenital blindness.
abstract: Leber congenital amaurosis (LCA) encompasses a set of early-onset blinding diseases that are characterized by vision loss, involuntary eye movement, and nonrecordable electroretinogram (ERG). At least 19 genes are associated with LCA, which is typically recessive; however, mutations in homeodomain transcription factor CRX lead to an autosomal dominant form of LCA. The mechanism of CRX-associated LCA is not understood. Here, we identified a spontaneous mouse mutant with a frameshift mutation in Crx (CrxRip). We determined that CrxRip is a dominant mutation that results in congenital blindness with nonrecordable response by ERG and arrested photoreceptor differentiation with no associated degeneration. Expression of LCA-associated dominant CRX frameshift mutations in mouse retina mimicked the CrxRip phenotype, which was rescued by overexpression of WT CRX. Whole-transcriptome profiling using deep RNA sequencing revealed progressive and complete loss of rod differentiation factor NRL in CrxRip retinas. Expression of NRL partially restored rod development in CrxRip/+ mice. We show that the binding of homeobox transcription factor OTX2 at the Nrl promoter was obliterated in CrxRip mice and ectopic expression of OTX2 rescued the rod differentiation defect. Together, our data indicate that OTX2 maintains Nrl expression in developing rods to consolidate rod fate. Our studies provide insights into CRX mutation-associated congenital blindness and should assist in therapeutic design.
authors.forename: Jerome E
authors.initials: JE
authors.lastname: Roger
authors.forename: Avinash
authors.initials: A
authors.lastname: Hiriyanna
authors.forename: Norimoto
authors.initials: N
authors.lastname: Gotoh
authors.forename: Hong
authors.initials: H
authors.lastname: Hao
authors.forename: Debbie F
authors.initials: DF
authors.lastname: Cheng
authors.forename: Rinki
authors.initials: R
authors.lastname: Ratnapriya
authors.forename: Marie-Audrey I
authors.initials: MA
authors.lastname: Kautzmann
authors.forename: Bo
authors.initials: B
authors.lastname: Chang
authors.forename: Anand
authors.initials: A
authors.lastname: Swaroop
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001766:Blindness / Q000151:congenital / Q000235:genetics*; D002454:Cell Differentiation; D003062:Codon; D003433:Crosses, Genetic; D004195:Disease Models, Animal; D004596:Electroretinography; D016368:Frameshift Mutation; D017353:Gene Deletion; D005786:Gene Expression Regulation; D005838:Genotype; D059014:High-Throughput Nucleotide Sequencing; D018398:Homeodomain Proteins / Q000235:genetics*; D006720:Homozygote; D057130:Leber Congenital Amaurosis / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D051857:Otx Transcription Factors / Q000235:genetics* / Q000502:physiology*; D010641:Phenotype; D012160:Retina / Q000378:metabolism; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000235:genetics*; D059467:Transcriptome
chemical_list: D003062:Codon; D018398:Homeodomain Proteins; D051857:Otx Transcription Factors; C497660:Otx2 protein, mouse; D015534:Trans-Activators; C109288:cone rod homeobox protein