Purpose: Mutations in the retinitis pigmentosa (RP) GTPase regulator (RPGR) gene account for more than 70% of X-linked RP cases. This study aims to characterize the proximal promoter region of the human RPGR gene.
Methods: The 5'-flanking region (5 kb) of human RPGR was cloned and sequenced. A potential transcription start site and transcription factor binding motifs were identified by bioinformatic analysis. Constructs containing the putative human RPGR promoter region upstream of a luciferase reporter gene were generated and analyzed by transient transfection and luciferase assays. Transgenic mouse lines carrying a 3-kb human RPGR promoter sequence fused to lacZ were generated and RPGR proximal promoter activity was analyzed by X-gal staining.
Results: Bioinformatic analyses of the human RPGR 5'-flanking region uncovered potential transcription factor binding sites and a CpG island. Transient transfection assays with RPGR promoter/luciferase reporter constructs revealed a 980-bp fragment (-952 to +28) that produced higher levels of luciferase activity. Mutagenesis identified a putative Sp1 binding site that was critical for regulating transcriptional activity. We generated transgenic mice in which a lacZ reporter gene was controlled by the 3-kb upstream region of RPGR. β-galactosidase expression was predominantly found in mouse retina, brain, and kidney. In the retina, the photoreceptor cell layer showed the strongest β-galactosidase staining.
Conclusions: Our study defined the human RPGR proximal promoter region in which a 3-kb fragment contained sufficient regulatory elements to control RPGR expression in mouse retina and other tissues. Characterization of the RPGR promoter will facilitate understanding of the functional role of RPGR in the retina and gene therapy of X-linked RP.
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http://dx.doi.org/10.1167/iovs.11-8811 | DOI Listing |
Int J Mol Sci
November 2024
Department of Ophthalmology, University Hospital, Ludwig-Maximilians-University, 80336 Munich, Germany.
Sci Data
November 2024
Qingdao Institute, College of Medicine, Fudan University, Qingdao, 266500, China.
EMBO J
December 2024
Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland.
Microtubules, composed of conserved α/β-tubulin dimers, undergo complex post-translational modifications (PTMs) that fine-tune their properties and interactions with other proteins. Cilia exhibit several tubulin PTMs, such as polyglutamylation, polyglycylation, detyrosination, and acetylation, with functions that are not fully understood. Mutations in AGBL5, which encodes the deglutamylating enzyme CCP5, have been linked to retinitis pigmentosa, suggesting that altered polyglutamylation may cause photoreceptor cell degeneration, though the underlying mechanisms are unclear.
View Article and Find Full Text PDFPLoS One
November 2024
Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
Sci Rep
October 2024
Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany.
Inherited retinal dystrophies (IRDs) and inherited optic neuropathies (IONs) are characterized by distinct genetic causes and molecular mechanisms that can lead to varying degrees of visual impairment. The discovery of pathogenic variants in numerous genes associated with these conditions has deepened our understanding of the molecular pathways that influence both vision and disease manifestation and may ultimately lead to novel therapeutic approaches. Over the past 18 years, our DNA diagnostics unit has been performing genetic testing on patients suspected of having IRD or ION, using state-of-the-art mutation detection technologies that are continuously updated.
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