title: Sox2 regulates cholinergic amacrine cell positioning and dendritic stratification in the retina.
abstract: The retina contains two populations of cholinergic amacrine cells, one positioned in the ganglion cell layer (GCL) and the other in the inner nuclear layer (INL), that together comprise ∼1/2 of a percent of all retinal neurons. The present study examined the genetic control of cholinergic amacrine cell number and distribution between these two layers. The total number of cholinergic amacrine cells was quantified in the C57BL/6J and A/J inbred mouse strains, and in 25 recombinant inbred strains derived from them, and variations in their number and ratio (GCL/INL) across these strains were mapped to genomic loci. The total cholinergic amacrine cell number was found to vary across the strains, from 27,000 to 40,000 cells, despite little variation within individual strains. The number of cells was always lower within the GCL relative to the INL, and the sizes of the two populations were strongly correlated, yet there was variation in their ratio between the strains. Approximately 1/3 of that variation in cell ratio was mapped to a locus on chromosome 3, where Sex determining region Y box 2 (Sox2) was identified as a candidate gene due to the presence of a 6-nucleotide insertion in the protein-coding sequence in C57BL/6J and because of robust and selective expression in cholinergic amacrine cells. Conditionally deleting Sox2 from the population of nascent cholinergic amacrine cells perturbed the normal ratio of cells situated in the GCL versus the INL and induced a bistratifying morphology, with dendrites distributed to both ON and OFF strata within the inner plexiform layer.
authors: Neuroscience Research Institute, Department of Molecular, Cellular and Developmental Biology, and.
authors: Irene E
authors: IE
authors: Whitney
authors: Neuroscience Research Institute, Department of Molecular, Cellular and Developmental Biology, and.
authors: Patrick W
authors: PW
authors: Keeley
authors: Neuroscience Research Institute.
authors: Ace J
authors: AJ
authors: St John
authors: Neuroscience Research Institute, Department of Psychological and Brain Sciences, University of California, Santa Barbara, California 93106, and.
authors: Amanda G
authors: AG
authors: Kautzman
authors: Departments of Neurobiology and Ophthalmology, Duke University Eye Center, Durham, North Carolina 27705.
authors: Jeremy N
authors: JN
authors: Kay
authors: Neuroscience Research Institute, Department of Psychological and Brain Sciences, University of California, Santa Barbara, California 93106, and breese@psych.ucsb.edu.
authors: Benjamin E
authors: BE
authors: Reese
mesh_terms: D025042:Amacrine Cells / Q000502:physiology*; D000818:Animals; D002452:Cell Count / Q000379:methods; D002478:Cells, Cultured; D059329:Cholinergic Neurons / Q000502:physiology*; D003712:Dendrites / Q000502:physiology*; D005260:Female; D008297:Male; D051379:Mice; D057507:Mice, 129 Strain; D008805:Mice, Inbred A; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D012160:Retina / Q000166:cytology* / Q000502:physiology*; D055748:SOXB1 Transcription Factors / Q000502:physiology*
chemical_list: D055748:SOXB1 Transcription Factors; C527783:Sox2 protein, mouse
keywords: P2X2; QTL; fate; migration; starburst; variant