Nrl and Sp nuclear proteins mediate transcription of rod-specific cGMP-phosphodiesterase beta-subunit gene: involvement of multiple response elements.
cGMP-phosphodiesterase (PDE) is the key effector in rod photoreceptor signal transduction. Mutations in the gene encoding its catalytic beta-subunit (beta-PDE) cause retinal degenerations leading to blindness. We report that the short -93 to +53 sequence in the upstream region of this gene is sufficient for beta-PDE transcription in both Y79 human retinoblastoma cells and Xenopus embryo heads maintained ex vivo. This sequence also functions as a minimal rod-specific promoter in transgenic Xenopus tadpoles. The Nrl transcription factor binds in vitro to the betaAp1/NRE regulatory element located within this region and transactivates it when overexpressed in nonretinal 293 embryonic kidney cells. We also found a G/C-rich activator element, beta/GC, important for promoter activity in Y79 retinoblastoma cells and Xenopus embryos. Both the ubiquitous Sp1 and the central nervous system-specific Sp4 transcription factors are expressed in retina and interact with this element in vitro. Electrophoretic mobilities of beta/GC-Y79 nuclear protein complexes are altered by antibodies against Sp1 and Sp4. Thus, our results implicate Nrl, Sp1, and Sp4 in transcriptional regulation of the rod-specific minimal beta-PDE promoter. We also conclude that Xenopus laevis is an efficient system for analyzing the human beta-PDE promoter and may be used to study other human retinal genes ex vivo and in vivo.
Lerner
L E
LE
Jules Stein Eye Institute and the Department of Ophthalmology, School of Medicine, University of California Los Angeles, Los Angeles, California 90095, USA.
Gribanova
Y E
YE
Ji
M
M
Knox
B E
BE
Farber
D B
DB
D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000235:genetics*; D000818:Animals; D054707:Cyclic Nucleotide Phosphodiesterases, Type 6; D005260:Female; D006367:HeLa Cells; D006801:Humans; D053703:Interleukin-11 Receptor alpha Subunit; D010727:Phosphoric Diester Hydrolases; D011401:Promoter Regions, Genetic; D018123:Receptors, Interleukin / Q000502:physiology*; D053702:Receptors, Interleukin-11; D020218:Response Elements; D017948:Retinal Rod Photoreceptor Cells / Q000201:enzymology*; D016329:Sp1 Transcription Factor / Q000502:physiology*; D051706:Sp4 Transcription Factor; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D014981:Xenopus
C508428:IL11RA protein, human; D053703:Interleukin-11 Receptor alpha Subunit; D018123:Receptors, Interleukin; D053702:Receptors, Interleukin-11; C497124:SP4 protein, human; D016329:Sp1 Transcription Factor; D051706:Sp4 Transcription Factor; D014157:Transcription Factors; D010727:Phosphoric Diester Hydrolases; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D054707:Cyclic Nucleotide Phosphodiesterases, Type 6; C517431:PDE6B protein, human