Promoter elements that mediate the pH response of PCK mRNA in LLC-PK1-F+ cells.
Promoter elements that mediate the pH response of PCK mRNA in LLC-PK1-F+ cells.
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在 LLC-PK1-F 细胞中介导 PCK mRNA pH 响应的启动子元件。
DOI：
10.1152/ajprenal.1996.271.2.f340
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Curthoys,NP
中科院分区：
文献类型：
--
作者：
Holcomb,T;Liu,W;Snyder,R;Shapiro,R;Curthoys,NP
代谢性酸中毒的发生导致肾组织磷酸烯醇式丙酮酸羧酸激酶(PCK)基因转录增加。当携带由PCK启动子-460到+73片段驱动的牛生长激素(BGH)基因的转基因小鼠被慢性酸化时，BGH mRNA在4天后增加一倍。融合细胞和分化良好的LLC-PK1-F+细胞在酸性介质(pH 6.9，10 mM HCO3-)中培养16h，PCK-pK1-F+细胞的PCK mRNA表达增加2.5倍，而转入PCK-490 CAT的融合细胞在酸性条件下培养48h，其氯霉素乙酰转移酶(CAT)活性增加3.5倍。P2元件的突变或缺失导致基础CAT活性下降4~5倍，但不影响pH反应。相反，P3(II)元件或Cre-1 cAMP反应元件的突变对基础活性几乎没有影响，但导致pH反应下降50%。其他缺失或突变对这两种活性几乎没有影响。因此，在代谢性酸中毒时，肾近端小管中与P3(II)和Cre-1元件结合的蛋白(S)的活性或水平的变化可能介导了PCK基因转录的增加。
The onset of metabolic acidosis causes an increased transcription of the renal phosphoenolpyruvate carboxykinase (PCK) gene. When transgenic mice carrying a bovine growth hormone (bGH) gene driven by the -460 to +73 segment of the PCK promoter were made chronically acidotic, the bGH mRNA was increased twofold after 4 days. Confluent and well-differentiated cultures of LLC-PK1-F+ cells exhibit a 2.5-fold increase in PCK mRNA when transferred to acidic media (pH 6.9, 10 mM HCO3-) for 16 h. Confluent cultures transfected with PCK-490 CAT exhibit an increase (3.5-fold) in chloramphenicol acetyltransferase (CAT) activity when shifted to acidic medium for 48 h. Mutation or deletion of the P2 element causes a four- to fivefold decrease in basal CAT activity but does not affect the pH response. In contrast, mutations of the P3(II) element or the CRE-1 cAMP-response element have little effect on basal activity but cause a 50% decrease in the pH response. Other deletions or mutations have little effect on either activity. Thus changes in the activity or levels of the protein(s) in the renal proximal tubule that binds to the P3(II) and CRE-1 elements may mediate increased transcription of the PCK gene during metabolic acidosis.