Garg Renu, Pandey Kailash N
Department of Physiology and Hypertension and Renal Center of Excellence, Tulane University Health Sciences Center and School of Medicine, New Orleans, LA 70112, USA.
Hypertension. 2003 Mar;41(3 Pt 2):730-6. doi: 10.1161/01.HYP.0000051890.68573.94. Epub 2003 Jan 13.
Atrial natriuretic peptide receptor A (NPRA) plays important role(s) in the control of extracellular fluid volume and blood pressure homeostasis. We have determined and analyzed the functional promoter region of Npr1 gene (coding for NPRA) and studied the effect of angiotensin (Ang) II on its promoter activity and expression in cultured mouse mesangial cells. The promoter analysis of Npr1 gene revealed the presence of positive regulatory cis-elements in the regions -1982 to -1841 bp and -916 to -496 bp and of the repressor elements in the regions -1841 to -916 bp and 56 to 382 bp relative to transcription start site. The Ang II pretreatment of cultured mouse mesangial cells transiently transfected with the promoter construct pNPRA-luc1 significantly inhibited the promoter activity in a time- and dose-dependent manner, with a maximum inhibition at 24 hours. The Ang II-dependent repression of Npr1 promoter activity was partially blocked by both angiotensin type 1 and type 2 antagonists candesartan and PD 123,319, respectively. The mRNA level of NPRA was also downregulated by Ang II treatment as determined by semiquantitative reverse transcriptase-polymerase chain reaction assay. The deletion analysis showed that the promoter region approximately 916 bp upstream of transcription start site contains the cis-elements involved in Ang II-mediated repression of transcription of Npr1 gene. The present study thus reveals the presence of functional cis-regulatory elements in the promoter region of the murine Npr1 gene and its transcriptional downregulation by vasoactive peptide Ang II.
心房利钠肽受体A（NPRA）在细胞外液容量控制和血压稳态调节中发挥重要作用。我们已经确定并分析了Npr1基因（编码NPRA）的功能启动子区域，并研究了血管紧张素（Ang）II对其启动子活性以及在培养的小鼠系膜细胞中表达的影响。Npr1基因的启动子分析显示，相对于转录起始位点，在-1982至-1841 bp和-916至-496 bp区域存在正调控顺式元件，在-1841至-916 bp和56至382 bp区域存在抑制元件。用启动子构建体pNPRA-luc1瞬时转染的培养小鼠系膜细胞经Ang II预处理后，以时间和剂量依赖性方式显著抑制启动子活性，在24小时时抑制作用最大。Ang II对Npr1启动子活性的抑制作用分别被1型和2型血管紧张素拮抗剂坎地沙坦和PD 123,319部分阻断。通过半定量逆转录-聚合酶链反应分析确定，Ang II处理也下调了NPRA的mRNA水平。缺失分析表明，转录起始位点上游约916 bp的启动子区域包含参与Ang II介导的Npr1基因转录抑制的顺式元件。因此，本研究揭示了小鼠Npr1基因启动子区域存在功能性顺式调控元件，以及血管活性肽Ang II对其转录的下调作用。
