Regulatory Sequences in the 3' Untranslated Region of the Human cGMP-Phosphodiesterase β-Subunit Gene

• Published in: Investigative ophthalmology & visual science Vol. 50; no. 6; pp. 2591 - 2598
• Main Authors: YERARDO, Mark R, VICZIAN, Andrea, PIRI, Natik, AKHMEDOV, Novrouz B, KNOX, Barry E, FARBER, Debora B
• Format: Journal Article
• Language: English
• Published: Rockville, MD Association for Research in Vision and Ophtalmology 01.06.2009
• Subjects: 3' Untranslated Regions - genetics; Animals; Base Sequence; Biological and medical sciences; Cyclic Nucleotide Phosphodiesterases, Type 6 - genetics; Embryo, Nonmammalian - metabolism; Eye and associated structures. Visual pathways and centers. Vision; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Enzymologic - physiology; Genes, Reporter; Humans; Kidney - embryology; Kidney - metabolism; Medical sciences; Molecular Sequence Data; Neuroblastoma - genetics; Ophthalmology; Regulatory Sequences, Nucleic Acid; Retina - metabolism; Retinal Neoplasms - genetics; Retinoblastoma - genetics; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; Transfection; Tumor Cells, Cultured - metabolism; Up-Regulation; Vertebrates: nervous system and sense organs; Xenopus laevis - genetics; Human; 3',5'-GMP; Regulatory sequence; Ophthalmology; Gene; Subunit
• ISSN: 0146-0404; 1552-5783; 1552-5783
• DOI: 10.1167/iovs.08-2010

Rod cGMP-phosphodiesterase, a key enzyme in visual transduction, is important for retinal integrity and function. Mutations in the gene encoding the phosphodiesterase beta-subunit (PDEbeta) cause retinal degeneration in animals and humans. Here the authors tested the hypothesis that elements in the 3' untranslated region (3' UTR) of the PDEbeta gene are involved in the regulation of PDEbeta expression. Involvement of the 3' UTR of PDEbeta mRNA in the regulation of PDEbeta expression was assessed by Y-79 retinoblastoma cells or the heads of Xenopus laevis tadpoles with constructs containing the SV40 or PDEbeta promoter, the luciferase cDNA, and either the SV40 or the PDEbeta 3' UTR (or fragments of its sequence). Compared with the SV40 3' UTR (used as control), the entire PDEbeta 3' UTR decreased reporter gene expression in Y-79 retinoblastoma cells as well as in SY5Y neuroblastoma and 293 human embryonic kidney cell lines. However, the authors observed that two 100-nucleotide fragments from the PDEbeta 3' UTR increased while its noncanonical poly-adenylation signal abolished reporter gene expression in Y-79 retinoblastoma cells and in ex vivo experiments using Xenopus tadpole heads. In particular, an 11-nucleotide element (EURE) in one of the 100-nucleotide fragments was responsible for the upregulation of luciferase expression. These studies indicate that the 3' UTR of the PDEbeta mRNA is involved in the complex regulation of this gene's expression in the retina. Moreover, the results show that the PDEbeta poly-A signal has a dominant inhibitory effect over two other regions in the 3' UTR that stimulate gene expression.