title: Top2b is involved in the formation of outer segment and synapse during late-stage photoreceptor differentiation by controlling key genes of photoreceptor transcriptional regulatory network.
abstract: Topoisomerase II beta (Top2b) is an enzyme that alters the topologic states of DNA during transcription. Top2b deletion in early retinal progenitor cells causes severe defects in neural differentiation and affects cell survival in all retinal cell types. However, it is unclear whether the observed severe phenotypes are the result of cell-autonomous/primary defects or non-cell-autonomous/secondary defects caused by alterations of other retinal cells. Using photoreceptor cells as a model, we first characterized the phenotypes in Top2b conditional knockout. Top2b deletion leads to malformation of photoreceptor outer segments (OSs) and synapses accompanied by dramatic cell loss at late-stage photoreceptor differentiation. Then, we performed mosaic analysis with shRNA-mediated Top2b knockdown in neonatal retina using in vivo electroportation to target rod photoreceptors in neonatal retina. Top2b knockdown causes defective OS without causing a dramatic cell loss, suggesting a Top2b cell-autonomous function. Furthermore, RNA-seq analysis reveals that Top2b controls the expression of key genes in the photoreceptor gene-regulatory network (e.g., Crx, Nr2e3, Opn1sw, Vsx2) and retinopathy-related genes (e.g., Abca4, Bbs7, Pde6b). Together, our data establish a combinatorial cell-autonomous and non-cell-autonomous role for Top2b in the late stage of photoreceptor differentiation and maturation. © 2017 The Authors Journal of Neuroscience Research Published by Wiley Periodicals, Inc.
authors.affiliation: Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey.
authors.forename: Hailing
authors.initials: H
authors.lastname: Hao
authors.affiliation: Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey.
authors.forename: Mavis R
authors.initials: MR
authors.lastname: Swerdel
authors.affiliation: Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey.
authors.forename: Hyeon-Yeol
authors.initials: HY
authors.lastname: Cho
authors.affiliation: Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey.
authors.forename: Ki-Bum
authors.initials: KB
authors.lastname: Lee
authors.affiliation: Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey.
authors.forename: Ronald P
authors.initials: RP
authors.lastname: Hart
authors.affiliation: Office of Research Commercialization, Rutgers University, Piscataway, New Jersey.
authors.forename: Yi Lisa
authors.initials: YL
authors.lastname: Lyu
authors.affiliation: Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey.
authors.forename: Li
authors.initials: L
authors.lastname: Cai
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D053263:Gene Regulatory Networks / Q000235:genetics*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D010786:Photoreceptor Cells / Q000166:cytology*; D000075223:Poly-ADP-Ribose Binding Proteins / Q000378:metabolism*; D012160:Retina / Q000196:embryology* / Q000254:growth & development; D013569:Synapses / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D000075223:Poly-ADP-Ribose Binding Proteins; D004250:DNA Topoisomerases, Type II; C000618815:Top2b protein, mouse
keywords: GSE86187; gene expression; neural development; neural differentiation; retina photoreceptors; transcriptional regulatory network