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α 2D/A ‐adrenergic receptor gene induction in the retina by phorbol ester: involvement of an AP‐2 element
Author(s) -
Venkataraman Venkateswar,
Duda Teresa,
Sharma Rameshwar K.
Publication year - 1999
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1046/j.1365-2443.1999.00249.x
Subject(s) - biology , microbiology and biotechnology , activator (genetics) , protein kinase c , phorbol , gene expression , messenger rna , reporter gene , receptor , gene , signal transduction , biochemistry
Background The α 2 ‐adrenergic receptor (α 2 ‐AR) expressed in the bovine retina has been demonstrated to be of the α 2D subtype. The bovine α 2D ‐adrenergic receptor (α 2D/A ‐AR) gene has been cloned and characterized. This report describes the induction of this gene by phorbol‐ 12, 13‐myristate acetate (PMA), an activator of protein kinase C (PKC). Results Treatment of the bovine retina for 60 min with PMA (1 μ m ) resulted in significant and similar increases in α 2D/A ‐AR mRNA level and gene transcription. This indicates that PMA causes α 2D/A ‐AR gene induction and that this induction takes place directly at the transcriptional level. In C6 cells, treatment with PMA at a concentration which was as low as 0.1 μ m induced endogenous α 2D/A ‐AR mRNA after 60 min. Luciferase reporter assays in C6 cells mapped the PMA‐responsive element to a region between −247 bp and −163 bp on the α 2D/A ‐AR promoter. Electrophoretic mobility shift assays showed an increased binding of nuclear factor(s) from PMA‐treated bovine retina to this promoter region. Competition assays indicate that an AP‐2 element may be involved in the PMA‐dependent induction. Conclusion These findings demonstrate for the first time, the direct induction of the α 2D/A ‐AR gene by PMA and support a role for an AP‐2 element in the induction mechanism.