Rod outer segment membrane guanylate cyclase type 1 (ROS-GC1) gene: structure, organization and regulation by phorbol ester, a protein kinase C activator.
At present there are two recognized members of the ROS-GC subfamily of membrane guanylate cyclases. They are ROS-GC1 and ROS-GC2. A distinctive feature of this family is that its members are not switched on by the extracellular peptide hormones; instead, they are modulated by intracellular Ca2+ signals, consistent to their linkage with phototransduction. An intriguing feature of ROS-GC1, which distinguishes it from ROS-GC2, is that it has two Ca2+ switches. One switch inhibits the enzyme at micromolar concentrations of Ca2+, as in phototransduction; the other, stimulates. The stimulatory switch, most likely, is linked to retinal synaptic activity. Thus, ROS-GC1 is linked to both phototransduction and the synaptic activity. The present study describes (1) the almost complete structural identity of 18.5 kb ROS-GC1 gene; (2) its structural organization: the gene is composed of 20 exons and 19 introns with classical GT/AG boundaries; (3) the activity of the ROS-GC1 promoter assayed through luciferase reporter in COS cells; and (4) induction of the gene by phorbol ester, a protein kinase C (PKC) activator. The co-presence of PKC and ROS-GC1 in photoreceptors suggests that regulation of the ROS-GC1 gene by PKC might be a physiologically relevant phenomenon.
Duda
T
T
Department of Cell Biology, University of Medicine and Dentistry of New Jersey, Stratford 08084, USA.
Venkataraman
V
V
Krishnan
A
A
Sharma
R K
RK
D000818:Animals; D001483:Base Sequence; D002417:Cattle; D015971:Gene Expression Regulation, Enzymologic; D006162:Guanylate Cyclase / Q000235:genetics* / Q000378:metabolism*; D008156:Luciferases / Q000378:metabolism; D008969:Molecular Sequence Data; D011493:Protein Kinase C / Q000096:biosynthesis*; D011956:Receptors, Cell Surface; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012374:Rod Cell Outer Segment / Q000201:enzymology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D011956:Receptors, Cell Surface; C110715:guanylate cyclase 1; D008156:Luciferases; D011493:Protein Kinase C; D006162:Guanylate Cyclase; D013755:Tetradecanoylphorbol Acetate