Characterization of the Human α1β1 Soluble Guanylyl Cyclase Promoter

Abstract

Soluble guanylyl cyclase (sGC) is the principal receptor for NO and plays a ubiquitous role in regulating cellular function. This is exemplified in the cardiovascular system where sGC governs smooth muscle tone and growth, vascular permeability, leukocyte flux, and platelet aggregation. As a consequence, aberrant NO-sGC signaling has been linked to diseases including hypertension, atherosclerosis, and stroke. Despite these key (patho)physiological roles, little is known about the expressional regulation of sGC. To address this deficit, we have characterized the promoter activity of human α1 and β1 sGC genes in a cell type relevant to cardiovascular (patho)physiology, primary human aortic smooth muscle cells. Luciferase reporter constructs revealed that the 0.3- and 0.5-kb regions upstream of the transcription start sites were optimal for α1 and β1 sGC promoter activity, respectively. Deletion of consensus sites for c-Myb, GAGA, NFAT, NF-κB(p50), and CCAAT-binding factor(s) (CCAAT-BF) revealed that these are the principal transcription factors regulating basal sGC expression. In addition, under pro-inflammatory conditions, the effects of the strongest α1 and β1 sGC repressors were enhanced, and enzyme expression and activity were reduced; in particular, NF-κB(p50) is pivotal in regulating enzyme expression under such conditions. NO itself also elicited a cGMP-independent negative feedback effect on sGC promoter activity that is mediated, in part, via CCAAT-BF activity. In sum, these data provide a systematic characterization of the promoter activity of human sGC α1 and β1 subunits and identify key transcription factors that govern subunit expression under basal and pro-inflammatory (i.e. atherogenic) conditions and in the presence of ligand NO. Soluble guanylyl cyclase (sGC) is the principal receptor for NO and plays a ubiquitous role in regulating cellular function. This is exemplified in the cardiovascular system where sGC governs smooth muscle tone and growth, vascular permeability, leukocyte flux, and platelet aggregation. As a consequence, aberrant NO-sGC signaling has been linked to diseases including hypertension, atherosclerosis, and stroke. Despite these key (patho)physiological roles, little is known about the expressional regulation of sGC. To address this deficit, we have characterized the promoter activity of human α1 and β1 sGC genes in a cell type relevant to cardiovascular (patho)physiology, primary human aortic smooth muscle cells. Luciferase reporter constructs revealed that the 0.3- and 0.5-kb regions upstream of the transcription start sites were optimal for α1 and β1 sGC promoter activity, respectively. Deletion of consensus sites for c-Myb, GAGA, NFAT, NF-κB(p50), and CCAAT-binding factor(s) (CCAAT-BF) revealed that these are the principal transcription factors regulating basal sGC expression. In addition, under pro-inflammatory conditions, the effects of the strongest α1 and β1 sGC repressors were enhanced, and enzyme expression and activity were reduced; in particular, NF-κB(p50) is pivotal in regulating enzyme expression under such conditions. NO itself also elicited a cGMP-independent negative feedback effect on sGC promoter activity that is mediated, in part, via CCAAT-BF activity. In sum, these data provide a systematic characterization of the promoter activity of human sGC α1 and β1 subunits and identify key transcription factors that govern subunit expression under basal and pro-inflammatory (i.e. atherogenic) conditions and in the presence of ligand NO. Nitric oxide is now well established to play key regulatory roles in numerous, disparate physiological and (patho)physiological processes (1Hobbs A.J. Ignarro L.J. Methods Enzymol. 1996; 269: 134-148Crossref PubMed Google Scholar, 2Murad F. Adv. Pharmacol. 1994; 26: 19-33Crossref PubMed Scopus (216) Google Scholar, 3Davis K.L. Martin E. Turko I.V. Murad F. Annu. Rev. Pharmacol. Toxicol. 2001; 41: 203-236Crossref PubMed Scopus (509) Google Scholar). Pivotal to NO-mediated modification of cell function is activation of the hemoprotein soluble guanylyl cyclase (sGC) 3The abbreviations used are: sGC, soluble guanylyl cyclase; TF, transcription factor; LPS, lipopolysaccharide; HASMC, human aortic smooth muscle cell; DETA-NO, DETA-NONOate; EMSA, electrophoretic mobility shift assay; NFY, nuclear factor Y; A, α fragment; B, β fragment. and consequent production of the second messenger cGMP, which in turn activates specific cyclic nucleotide-dependent protein kinases, ion channels, and phosphodiesterases (4Hobbs A.J. Trends Pharmacol. Sci. 1997; 18: 484-491Abstract Full Text PDF PubMed Scopus (244) Google Scholar). This fundamental role for sGC as the principal intracellular receptor for NO is exemplified in the cardiovascular system, where the enzyme governs smooth muscle tone (5Rapoport R.M. Murad F. J. Cyclic. Nucleotide. Protein Phosphor. Res. 1983; 9: 281-296PubMed Google Scholar) and growth (6Garg U.C. Hassid A. J. Clin. Investig. 1989; 83: 1774-1777Crossref PubMed Scopus (1997) Google Scholar), vascular permeability (7Kubes P. Am. J. Physiol. 1993; 265: H1909-H1915PubMed Google Scholar, 8Kurose I. Kubes P. Wolf R. Anderson D.C. Paulson J. Miyasaka M. Granger D.N. Circ. Res. 1993; 73: 164-171Crossref PubMed Scopus (339) Google Scholar), platelet reactivity (9Radomski M.W. Palmer R.M. Moncada S. Biochem. Biophys. Res. Commun. 1987; 148: 1482-1489Crossref PubMed Scopus (665) Google Scholar, 10Hobbs A.J. Moncada S. Vascul. Pharmacol. 2003; 40: 149-154Crossref PubMed Scopus (48) Google Scholar), and leukocyte extravasation (11Niu X.F. Ibbotson G. Kubes P. Circ. Res. 1996; 79: 992-999Crossref PubMed Scopus (61) Google Scholar, 12Ahluwalia A. Foster P. Scotland R.S. McLean P.G. Mathur A. Perretti M. Moncada S. Hobbs A.J. Proc. Natl. Acad. Sci. U. S. A. 2004; 101: 1386-1391Crossref PubMed Scopus (186) Google Scholar). Soluble GC functions as an obligate heterodimer composed of α and β subunits (13Kamisaki Y. Saheki S. Nakane M. Palmieri J.A. Kuno T. Chang B.Y. Waldman S.A. Murad F. J. Biol. Chem. 1986; 261: 7236-7241Abstract Full Text PDF PubMed Google Scholar). Within the last decade, the localization and structure of the genes encoding for sGC subunits have been elucidated in several mammalian species, nonvertebrates, and plants (14Andreopoulos S. Papapetropoulos A. Gen. Pharmacol. 2000; 34: 147-157Crossref PubMed Scopus (67) Google Scholar). In mammals, two isoforms of each subunit, called α1,2 and β1,2, have been cloned and characterized (15Zabel U. Weeger M. La M. Schmidt H.H. Biochem. J. 1998; 335: 51-57Crossref PubMed Scopus (125) Google Scholar). However, to date only α1/β1 and α2/β1 heterodimers have been identified at the protein level. The chromosomal localization of sGC genes has been determined in rodents (16Azam M. Gupta G. Chen W. Wellington S. Warburton D. Danziger R.S. Hypertension. 1998; 32: 149-154Crossref PubMed Scopus (33) Google Scholar, 17Sharina I.G. Krumenacker J.S. Martin E. Murad F. Proc. Natl. Acad. Sci. U. S. A. 2000; 97: 10878-10883Crossref PubMed Scopus (35) Google Scholar) and humans (18Giuili G. Roechel N. Scholl U. Mattei M.G. Guellaen G. Hum. Genet. 1993; 91: 257-260Crossref PubMed Scopus (35) Google Scholar); in both cases the α1 and β1 subunits are co-localized on the same locus, whereas α2 and β2 lie on separate chromosomes. Previous reports have provided evidence that expressional regulation of the enzyme is a key means of modulating NO-sGC signaling. For instance, different tissues possess distinct levels of mRNA for sGC isoforms (19Budworth J. Meillerais S. Charles I. Powell K. Biochem. Biophys. Res. Commun. 1999; 263: 696-701Crossref PubMed Scopus (106) Google Scholar), intimating tissue-specific expression of individual sGC subunits. Furthermore, splice variants of the α1 sGC subunit mRNA have been identified (20Ritter D. Taylor J.F. Hoffmann J.W. Carnaghi L. Giddings S.J. Zakeri H. Kwok P.Y. Biochem. J. 2000; 346: 811-816Crossref PubMed Google Scholar). In contrast, the human β1 subunit is encoded by a single transcript (∼3.5kb), suggesting the translation of a single protein. Such observations suggest that the expression of the β1 subunit is somewhat invariant, whereas alterations in the expression of the α subunit(s) may be an important physiological control mechanism. Changes in the expression of sGC have also been linked with disease intimating that expressional regulation of the enzyme is to have (patho)physiological For instance, in and expression of the β1 subunit is and with in H. U. W. Schmidt H.H. Circ. Res. 1999; PubMed Scopus Google Scholar, S. A. A. Hypertension. 2000; PubMed Scopus Google Scholar). in is with and expression of the β1 and β2 suggesting that of β subunits may be to regulation (16Azam M. Gupta G. Chen W. Wellington S. Warburton D. Danziger R.S. Hypertension. 1998; 32: 149-154Crossref PubMed Scopus (33) Google Scholar). In of hypertension, sGC expression is J.A. 2001; PubMed Scopus Google Scholar, S. M. J. S. Am. J. Physiol. PubMed Scopus Google Scholar), and smooth muscle to to sGC G. M. Am. J. Biol. 2004; PubMed Scopus Google Scholar). β1 sGC expression also with L. G. J.W. S. G. Circ. Res. 2000; PubMed Scopus Google Scholar). of tissues to pro-inflammatory NO also in sGC expression. For and NO sGC β1 mRNA expression in smooth muscle A. G. N. Murad F. J. Pharmacol. 1996; PubMed Scopus Google Scholar), and in sGC expression is linked to signaling and D. U. J. A. Schmidt H.H. Proc. Natl. Acad. Sci. U. S. A. 2004; 101: PubMed Scopus Google Scholar). In contrast, β1 subunit expression has been linked to in with M. A. I. R. Proc. Natl. Acad. Sci. U. S. A. 2000; 97: PubMed Scopus Google Scholar, K. S. R. M. M. J. Biol. Chem. 2003; Full Text Full Text PDF PubMed Scopus Google Scholar) and in aortic J. A. D. K. R. G. 1999; PubMed Scopus Google Scholar). observations that expressional regulation of sGC plays a key role in the cardiovascular system, both in of physiological and Despite these is a of the regulation of sGC promoter activity, in the human where the enzyme such an important physiological function. Previous have the promoter activity of individual sGC subunits in different M. S. A. Biochem. Biophys. Res. Commun. 2004; PubMed Scopus Google Scholar, T. N. Biochem. J. PubMed Google Scholar), only a single has on the human β1 I.G. Martin E. A. K.L. Murad F. Proc. Natl. Acad. Sci. U. S. A. 2003; PubMed Scopus Google Scholar). a key role for a CCAAT-binding factor (CCAAT-BF) this in a cell is a key to the factors regulating human α1 and β1 sGC promoter activity in the human to the physiological roles and regulation of the NO receptor and aberrant expression may cardiovascular To address this we the regulation of human α1 and β1 sGC genes in human aortic smooth muscle were in smooth muscle cell growth with human growth human growth human and The were at and and in were of for α1 and β1 sGC α1 β1 sGC subunits were to the The of human α1 and β1 sGC were the by on the regions of α1 and β1 sGC genes including the The of both promoter regions by of Luciferase Deletion regions of the α1 and β1 sGC genes upstream of the transcription start and to the of the were cloned sites of the reporter were by as for the in the reporter were identified by and the of the constructs by used to the and constructs are in and were to by the and This also used to the of of the constructs were by and were in The were with of with a control used as a In each the were with a at a where were with and in cell the NO Luciferase the were in and for at the Luciferase activity determined the reporter system on the activity to and the data are as in were for with the pro-inflammatory nuclear were and were to EMSA, as we have L. M. Moncada S. Hobbs A.J. J. 2001; PubMed Scopus Google Scholar). The used to the are in were determined by protein by of protein were to under conditions. The were to a the cell The were with to and in in at with The were with primary in in for at with by The were with for at with in in The were as and the were The were by were in and to the pro-inflammatory for a this the were by and at for The cell in and with The were to for and the by at for The cyclic a and used to identify and α1 sGC and human at The The α1 sGC upstream for the presence of regions and of promoter with and of In for transcription sites with K. K. H. E. T. Res. PubMed Scopus Google Scholar). The are as the means used to data where of the of α1 and β1 sGC start sites were determined by of α1 and β1 sGC regions with the mRNA and both α1 and β1 sGC with the for in to the transcription start of both α1 and β1 sGC of promoter S. PubMed Scopus Google Scholar) the presence of consensus and the in the α1 sGC promoter For the β1 sGC only were GC and CCAAT-BF were in both Furthermore, we were to identify in the α1 sGC promoter only in the β1 promoter the presence of in the α1 β1 sGC are to the transcription start of of α1 sGC promoter to GC β1 sGC promoter to GC GC GC in a of the reporter constructs of human α1 of human β1 sGC upstream were for promoter activity in The the of activity the α1 sGC promoter constructs activity in the constructs the presence of The and the of activity the β1 sGC promoter constructs The a promoter activity, suggesting the presence of a and of the promoter to in the activity of the suggesting the of activation in that However, the in in activity, suggesting that a is and In the and constructs the for promoter activity of the α1 and β1 sGC and were the only with the and and the a with the As a consequence, is to be disparate regulation of sGC expression (i.e. promoter species, the of the activity of the human promoter in human cells. of of transcription sites in the the promoter activity for the human α1 and β1 sGC genes and and by In both and sites for several transcription factors at the optimal regulatory the transcription start were To the of these for α1 and β1 sGC promoter activity, the of each were in both the and basal constructs via sites as by with activity of these constructs in and sites that a effect on sGC promoter activity in are in and for and sites in promoter activity with control in suggesting that of these to sites has effects on α1 sGC promoter activity in these cells. The effect of in suggesting a effect the effects of and were also in activity. However, CCAAT-BF a effect in suggesting that this may to the basal transcription for α1 sGC in cell a for an in promoter activity with control in This effect in suggesting that NF-κB(p50) plays a key role in the basal expression of β1 sGC, of cell In contrast, a for both sites a in promoter activity in suggesting a effect of this The effect of in and in a human cell I.G. Martin E. A. K.L. Murad F. Proc. Natl. Acad. Sci. U. S. A. 2003; PubMed Scopus Google Scholar), suggesting that a effect of is in and and in in suggesting regulation of sGC promoter activity. of on sGC in vascular sGC expression in human α1 and β1 sGC promoter activity in the presence of a pro-inflammatory the and conditions both the α1 and β1 sGC promoter activity at revealed a in sGC β1 expression of the to the pro-inflammatory that by a in both the basal and sGC activity As in CCAAT-BF and the effect on α1 and β1 sGC promoter activity, the To these transcription factors to the on the nuclear were by In of the α1 sGC were the to upstream of the start The of these by a of the of in the presence of an of the nuclear with the pro-inflammatory an in the of two of these suggesting that vascular the of CCAAT-BF to the α1 sGC The of a single of the of the CCAAT-BF the of two of the the of that single for the of the CCAAT-BF to the For the β1 sGC the were also a to of this promoter were of the with nuclear were in the presence of an of a of the only we used an suggesting that the subunit as a is pivotal in regulating sGC β1 this well with the in sGC β1 promoter activity in the with consensus and with reports a activity of L. R. Biochem. 2004; 265: PubMed Scopus Google Scholar, H. S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). the nuclear with the pro-inflammatory an in the of the suggesting that vascular the of the NF-κB(p50) factor to the β1 sGC The of the for the the of two and the of the that the is for Furthermore, an important role for in regulating the expression of the β1 subunit by a in enzyme protein expression and activity and of NO on sGC in the effect of the sGC ligand NO on expression of the enzyme in the of a feedback in of enzyme which is well established to K. S. R. M. M. J. Biol. Chem. 2003; Full Text Full Text PDF PubMed Scopus Google Scholar, M. M. Hobbs A.J. J. Pharmacol. PubMed Scopus Google human α1 and β1 sGC promoter activity in the presence of the NO NO in D. J. Pharmacol. 1993; PubMed Scopus Google revealed that for the α1 subunit, the promoter activity to the in the suggesting that key repressors are in this of the For β1 sGC, in the suggesting that this of the promoter the were these that NO a of both α1 and β1 sGC promoter activity. This effect at DETA-NO, which in an NO of M. M. N. D. Moncada S. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar). the of promoter activity by NO a to that under pro-inflammatory conditions with effect at To the activity of NO were the and constructs as of promoter function. the of both the α1 and β1 sGC promoter in the presence of the sGC by the and that the effect of NO on sGC promoter activity and expression is via activation of the enzyme In an to identify transcription factors that the effects of and constructs with in specific sites were for to NO. the activity of the with a CCAAT-BF to by intimating that this is in the negative feedback effect of NO on sGC expression. In contrast, of the same in the promoter activity in the presence of NO. we the of NO in sGC promoter activity via the CCAAT-BF by In with the an in the of the CCAAT-BF that with a CCAAT-BF However, to a in the CCAAT-BF with specific to two we were to such a suggesting that are of sGC is for NO-mediated regulation of vascular smooth muscle reactivity (5Rapoport R.M. Murad F. J. Cyclic. Nucleotide. Protein Phosphor. Res. 1983; 9: 281-296PubMed Google Scholar) and (6Garg U.C. Hassid A. J. Clin. Investig. 1989; 83: 1774-1777Crossref PubMed Scopus (1997) Google Scholar), permeability (7Kubes P. Am. J. Physiol. 1993; 265: H1909-H1915PubMed Google Scholar, 8Kurose I. Kubes P. Wolf R. Anderson D.C. Paulson J. Miyasaka M. Granger D.N. Circ. Res. 1993; 73: 164-171Crossref PubMed Scopus (339) Google Scholar), and the of (9Radomski M.W. Palmer R.M. Moncada S. Biochem. Biophys. Res. Commun. 1987; 148: 1482-1489Crossref PubMed Scopus (665) Google Scholar) and I. Kubes P. Wolf R. Anderson D.C. Paulson J. Miyasaka M. Granger D.N. Circ. Res. 1993; 73: 164-171Crossref PubMed Scopus (339) Google Scholar, X.F. Ibbotson G. Kubes P. Circ. Res. 1996; 79: 992-999Crossref PubMed Scopus (61) Google Scholar). As under physiological activation of sGC is fundamental to cardiovascular and an important sGC activity may be for several of cardiovascular including (i.e. smooth muscle and cellular of sGC is to have at an on as NO in the expressional regulation of this enzyme are to on the of Despite this the physiological regulation and alterations of sGC expression. To address this deficit, we have characterized the human α1 and β1 sGC promoter regions in human aortic smooth muscle cells. of the human α1 and β1 sGC revealed of regulation of these genes and in the promoter consensus sGC genes have a promoter and CCAAT-BF sites in upstream the transcription start in with the for R. P. Annu. Rev. Biochem. PubMed Scopus Google Scholar). the are in human promoter regions to S. PubMed Scopus Google Scholar); in the α1 β1 sGC However, the α1 sGC promoter two an transcription start by the of Biophys. 1997; PubMed Scopus Google Scholar) be an is in the human β1 sGC of constructs different of the α1 and β1 sGC regions a different of activity both subunit in Despite α1 sGC the promoter activity in the suggesting the different for β1 sGC. the the promoter activity, and the presence of several and repressors at a this regulatory The that activity with activity in has been to be in I.G. Martin E. A. K.L. Murad F. Proc. Natl. Acad. Sci. U. S. A. 2003; PubMed Scopus Google Scholar), a regulation of the promoter to the β1 sGC promoter activity in This effect is also by the that activity is the same as and in intimating in the to in I.G. Martin E. A. K.L. Murad F. Proc. Natl. Acad. Sci. U. S. A. 2003; PubMed Scopus Google Scholar). and constructs the promoter activity in that the regulatory promoter of sGC has the for promoter activity in the upstream of the transcription start also on the of principal for the regulation of α1 and β1 sGC in of transcription sites by are in both and promoter of which have been to play an important role in the transcription of a of of the cardiovascular factor of the and factor; of the have consensus in both and of these factors may have a regulatory role in the of both α1 and β1 sGC this is for the α1 and β1 and which are the CCAAT-BF and the transcription start and are to play key roles in expressional regulation of sGC in the α1 and β1 sGC promoter regions consensus for to play a role in regulating a key role for sGC in this I.G. Martin E. A. K.L. Murad F. Proc. Natl. Acad. Sci. U. S. A. 2003; PubMed Scopus Google Scholar). with a α1 sGC reporter a c-Myb, GAGA, NFAT, CCAAT-BF in the promoter that the of these sites is important for transcription in The and to a the and effects were in intimating a vascular smooth muscle In plays a role in smooth muscle cell with cell as in W. T. R. M. Circ. Res. 2003; PubMed Scopus Google Scholar) and is with and vascular smooth muscle D.C. Trends 2003; PubMed Scopus Google Scholar); the physiological of NO-sGC signaling in these processes with the of such to sGC promoter activity and However, is that two sites at and in α1 sGC were α1 sGC promoter activity. with a β1 sGC reporter a in the promoter revealed that this is for transcription activation in this effect in and I.G. Martin E. A. K.L. Murad F. Proc. Natl. Acad. Sci. U. S. A. 2003; PubMed Scopus Google Scholar). also that the of an NF-κB(p50) is important for transcription in both and suggesting that this is important in expression. To the of these in regulation of sGC promoter activity, we to the of CCAAT-BF and with the sGC promoter is these data that both CCAAT-BF and NF-κB(p50) to the α1 and β1 sGC promoter and that the effects of these on sGC promoter activity are CCAAT-BF has been to be in the of cell genes R. 1999; PubMed Scopus Google Scholar) and is known to be for cell activation and of several mammalian genes R. J. Biol. Chem. 2000; Full Text Full Text PDF PubMed Scopus Google Scholar, J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, G. M. W. U. K. R. J. Biol. Chem. 2003; Full Text Full Text PDF PubMed Scopus Google Scholar). In to the by I.G. Martin E. A. K.L. Murad F. Proc. Natl. Acad. Sci. U. S. A. 2003; PubMed Scopus Google Scholar), a second upstream also to have an important the role plays in β1 sGC the presence of the two sites in the promoter is in with the that expression of β1 sGC be the cell I.G. Martin E. A. K.L. Murad F. Proc. Natl. Acad. Sci. U. S. A. 2003; PubMed Scopus Google Scholar). cardiovascular atherosclerosis, are now to a of the signaling an important of the expressional regulation of sGC in a pro-inflammatory is to provide the of vascular To such a in the we the effect of pro-inflammatory conditions on sGC promoter activity in and were in the presence of a pro-inflammatory such conditions, sGC and promoter activity at a regulation of both α1 and β1 sGC expression. The that the strongest repressors for α1 β1 sGC and under pro-inflammatory conditions at in part, the in α1 and β1 sGC promoter activity under this of protein expression that the promoter activity in the presence of pro-inflammatory by in both sGC β1 protein expression and activity, a key and regulation of sGC also the effect of NO to a feedback and sGC promoter the NO DETA-NO, we that NO a in α1 and β1 sGC promoter activity. In these the effect of NO at DETA-NO, which in an NO of M. M. N. D. Moncada S. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar), to with NO activity and conditions by NO the effects of NO in this to be effects on activity has been for M. Res. 1996; PubMed Scopus Google Scholar) and Pharmacol. 2000; PubMed Scopus Google also revealed that a CCAAT-BF is pivotal to the effects of at in of the α1 subunit, of this to to NO. several this is to which be to to the of this TF, we were to the we negative for and suggesting that is of these The and in sGC promoter activity and protein expression be to a negative feedback regulation of sGC expression in cardiovascular with NO such as be for sGC expression to be to the NO levels and the data also suggest that the in sGC mRNA levels in vascular smooth muscle in to A. G. N. Murad F. J. Pharmacol. 1996; PubMed Scopus Google Scholar), M. G. H. F. S. Am. J. Physiol. 2001; PubMed Google Scholar), and NO G. J. Clin. Investig. 1997; PubMed Scopus Google Scholar, J. Res. 1998; 79: Full Text PDF PubMed Scopus Google Scholar) is to be at in part, to a in sGC promoter activity via and In sum, these data provide a of human sGC promoter regulation in and has identified important factors regulating human sGC expression a cell system relevant to cardiovascular and observations suggest that expressional regulation of human sGC α1 and β1 subunit both and is to play an important role in the (patho)physiological regulation of enzyme activity. As these a in the of expressional regulation of the genes encoding sGC subunits and provide that in aberrant NO-sGC signaling. with