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Ledford KL, Martinez-De Luna RI, Theisen MA, Rawlins KD, Viczian AS, Zuber ME. Distinct cis-acting regions control six6 expression during eye field and optic cup stages of eye formation. Dev Biol 2017; 426:418-428. [PMID: 28438336 PMCID: PMC5500183 DOI: 10.1016/j.ydbio.2017.04.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/07/2017] [Accepted: 04/12/2017] [Indexed: 02/06/2023]
Abstract
The eye field transcription factor, Six6, is essential for both the early (specification and proliferative growth) phase of eye formation, as well as for normal retinal progenitor cell differentiation. While genomic regions driving six6 optic cup expression have been described, the sequences controlling eye field and optic vesicle expression are unknown. Two evolutionary conserved regions 5' and a third 3' to the six6 coding region were identified, and together they faithfully replicate the endogenous X. laevis six6 expression pattern. Transgenic lines were generated and used to determine the onset and expression patterns controlled by the regulatory regions. The conserved 3' region was necessary and sufficient for eye field and optic vesicle expression. In contrast, the two conserved enhancer regions located 5' of the coding sequence were required together for normal optic cup and mature retinal expression. Gain-of-function experiments indicate endogenous six6 and GFP expression in F1 transgenic embryos are similarly regulated in response to candidate trans-acting factors. Importantly, CRISPR/CAS9-mediated deletion of the 3' eye field/optic vesicle enhancer in X. laevis, resulted in a reduction in optic vesicle size. These results identify the cis-acting regions, demonstrate the modular nature of the elements controlling early versus late retinal expression, and identify potential regulators of six6 expression during the early stages of eye formation.
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Affiliation(s)
- Kelley L Ledford
- Department of Ophthalmology and The Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY 13210, United States; Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, United States
| | - Reyna I Martinez-De Luna
- Department of Ophthalmology and The Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY 13210, United States
| | - Matthew A Theisen
- Department of Ophthalmology and The Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY 13210, United States
| | - Karisa D Rawlins
- Department of Ophthalmology and The Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY 13210, United States
| | - Andrea S Viczian
- Department of Ophthalmology and The Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY 13210, United States; Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, United States; Department of Cell & Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, United States; Department of Neuroscience & Physiology, SUNY Upstate Medical University, Syracuse, NY 13210, United States.
| | - Michael E Zuber
- Department of Ophthalmology and The Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY 13210, United States; Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, United States; Department of Neuroscience & Physiology, SUNY Upstate Medical University, Syracuse, NY 13210, United States
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Anderson J, Salzer CL, Kumar JP. Regulation of the retinal determination gene dachshund in the embryonic head and developing eye of Drosophila. Dev Biol 2006; 297:536-49. [PMID: 16780828 PMCID: PMC2717003 DOI: 10.1016/j.ydbio.2006.05.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Revised: 04/13/2006] [Accepted: 05/03/2006] [Indexed: 11/29/2022]
Abstract
The retinal determination gene dachshund is distantly related to the family of Ski/Sno proto-oncogenes and influences the development of a wide range of tissues including the embryonic head, optic lobes, brain, central nervous system as well as the post-embryonic leg, wing, genital and eye-antennal discs. We were interested in the regulatory mechanisms that control the dynamic expression pattern of dachshund and in this report we set out to ascertain how the transcription of dachshund is modulated in the embryonic head and developing eye-antennal imaginal disc. We demonstrate that the TGFbeta signaling cascade, the transcription factor zerknullt and several other patterning genes prevent dachshund from being expressed inappropriately within the embryonic head. Additionally, we show that several members of the eye specification cascade influence the transcription of dachshund during normal and ectopic eye development. Our results suggest that dachshund is regulated by a complex combinatorial code of transcription factors and signaling pathways. Unraveling this code may lead to an understanding of how dachshund regulates the development of many diverse tissue types including the eye.
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Affiliation(s)
- Jason Anderson
- Department of Biology, Indiana University, 1001 E. 3rd Street, Bloomington, IN 47401, USA
| | - Claire L. Salzer
- Department of Biology, Indiana University, 1001 E. 3rd Street, Bloomington, IN 47401, USA
| | - Justin P. Kumar
- Department of Biology, Indiana University, 1001 E. 3rd Street, Bloomington, IN 47401, USA
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Roederer K, Cozy L, Anderson J, Kumar JP. Novel dominant-negative mutation within the six domain of the conserved eye specification gene sine oculis inhibits eye development in Drosophila. Dev Dyn 2005; 232:753-66. [PMID: 15704100 PMCID: PMC2737192 DOI: 10.1002/dvdy.20316] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The development of the compound eye of Drosophila is controlled, in part, by the concerted actions of several nuclear proteins that form an intricate regulatory system. One member of this network is sine oculis (so), the founding member of the Six gene family. Mutations within so affect the entire visual system, including the compound eye. The vertebrate homologs Six3 and Six6 also appear to play crucial roles in retinal formation. Mutations in Six3 inhibit retinal formation in chickens and fish, whereas those in Six6 are the underlying cause of bilateral anophthalmia in humans. Together, these phenotypes suggest a conserved role for the Six genes in eye development. In this report, we describe the effects of a dominant-negative mutation of sine oculis on the development of the compound eye of Drosophila. The mutation resides within the Six domain and may have implications for eye development and disease.
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Affiliation(s)
| | - Loralyn Cozy
- Department of Biology, Indiana University, Bloomington, Indiana
| | - Jason Anderson
- Department of Biology, Indiana University, Bloomington, Indiana
| | - Justin P. Kumar
- Department of Biology, Indiana University, Bloomington, Indiana
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