Ferritin gene expression and transferrin receptor activity in intestine of rats with varying iron stores
Ferritin gene expression and transferrin receptor activity in intestine of rats with varying iron stores
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DOI：
10.1152/ajpgi.1997.273.3.g636
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发表时间：
1997-09-01
影响因子：
4.5
通讯作者：
Morgan, EH
中科院分区：
文献类型：
--
作者：
Oates, PS;Morgan, EH
转铁蛋白受体和铁蛋白基因的表达以前已被证明是在转录和转录后调节，后者是根据细胞铁水平的间接调节。本研究探讨了转铁蛋白受体功能和铁蛋白基因表达沿着隐窝绒毛轴的大鼠肠道不同的铁储存。通过饲喂对照日粮和低铁或高铁（2%羰基铁）的日粮8-10周来产生改变的铁储备。铁蛋白基因的表达和活性分别通过原位杂交和免疫组织化学定位进行评估。转铁蛋白受体活性测定的静脉注射转铁蛋白结合铁的吸收，并显示出增加与铁负荷的水平。在所有铁状态组中，铁蛋白mRNA在固有层内的隐窝上皮细胞和巨噬细胞中水平最高，而在绒毛上皮细胞中水平较低。在所有组中，铁蛋白在隐窝区域中未见，但在对照组和铁负载组（但非缺铁组）大鼠的绒毛细胞的顶端三分之二中染色增加。铁蛋白染色随铁负荷增加而增加。我们的结论是，在未分化的隐窝细胞铁蛋白基因的转录，但信息不翻译。分化后，这些基因似乎是由细胞铁储存转录后控制。
Expression of transferrin receptor and ferritin genes has been shown previously to be under transcriptional and posttranscriptional regulation, the latter being reciprocally regulated according to cellular iron levels. This study examined transferrin receptor function and ferritin gene expression along the crypt-villus axis of the intestinal tract in rats with varying iron stores. Altered iron stores were produced by feeding a control diet and diets low or high in iron (2% carbonyl iron) for 8-10 wk. Expression and activity of the ferritin genes were assessed by in situ hybridization and immunohistochemical localization, respectively. Transferrin receptor activity was determined by the uptake of intravenously injected transferrin-bound iron and was shown to increase with the level of iron loading. In all iron status groups, ferritin mRNA was seen at highest levels in the epithelial cells of the crypt and macrophages within the lamina propria and at lower levels in villus epithelial cells. In all groups, ferritin protein was not seen in the crypt region but was seen with increasing staining in the apical two-thirds of the villus cells of control and iron-loaded, but not iron-deficient, rats. Ferritin staining increased with iron loading. We conclude that in undifferentiated crypt cells ferritin genes are transcribed, but the message is not translated. After differentiation, these genes appear to be controlled posttranscriptionally by cellular iron stores.