Huang H, Rajkumar K, Murphy L J
Department of Internal Medicine, University of Manitoba, Winnipeg, Canada.
J Endocrinol. 1997 Jan;152(1):99-108. doi: 10.1677/joe.0.1520099.
The hepatic and renal expressions of the insulin-like growth factor binding proteins (IGFBPs) were examined in transgenic (Tg) mice which overexpress a rat IGFBP-1 transgene driven by the phosphoglycerate kinase-1 promoter. There were no significant difference in the abundance of serum IGFBPs in Tg and wild-type (Wt) mice. Although total hepatic IGFBP-1 mRNA mouse and transgene-derived) levels were similar in Tg mice to the levels of mouse IGFBP-1 mRNA in Wt mice on day 1 of life, in Tg mice only approximately 30% of the IGFBP-1 mRNA was derived from transcription of the mouse gene. An age-related decline in hepatic IGFBP-1 mRNA levels was apparent in both Tg and Wt mice. Food deprivation resulted in increased levels of mouse IGFBP-1 mRNA but the total IGFBP-1 mRNA levels were not significantly different in Tg and Wt mice. In the kidney, unlike the liver, IGFBP-1 mRNA levels in Tg mice were markedly elevated compared with Wt mice and no significant decline was seen with age. Northern blots of hepatic and renal RNA demonstrated similar levels of IGFBP-3, -4, -5 and -6 mRNAs in Tg and Wt mice. From these data we can conclude that in the liver expression of the transgene leads to a coordinated reduction in mouse IGFBP-1 mRNA levels.
在过表达由磷酸甘油酸激酶-1启动子驱动的大鼠胰岛素样生长因子结合蛋白1（IGFBP-1）转基因的转基因（Tg）小鼠中，检测了胰岛素样生长因子结合蛋白（IGFBPs）在肝脏和肾脏中的表达情况。Tg小鼠和野生型（Wt）小鼠血清IGFBPs的丰度没有显著差异。虽然在出生第1天，Tg小鼠肝脏中总的IGFBP-1 mRNA（小鼠的和转基因来源的）水平与Wt小鼠中IGFBP-1 mRNA水平相似，但在Tg小鼠中，只有约30%的IGFBP-1 mRNA来自小鼠基因的转录。在Tg小鼠和Wt小鼠中，肝脏IGFBP-1 mRNA水平均出现了与年龄相关的下降。禁食导致小鼠IGFBP-1 mRNA水平升高，但Tg小鼠和Wt小鼠总的IGFBP-1 mRNA水平没有显著差异。在肾脏中，与肝脏不同，Tg小鼠的IGFBP-1 mRNA水平与Wt小鼠相比显著升高，且未观察到随年龄增长有显著下降。肝脏和肾脏RNA的Northern印迹显示，Tg小鼠和Wt小鼠中IGFBP-3、-4、-5和-6 mRNA水平相似。从这些数据我们可以得出结论，在肝脏中，转基因的表达导致小鼠IGFBP-1 mRNA水平协同降低。
