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Increasing dietary protein selectively upregulates the DMT1 isoform that contains an iron responsive element
Author(s) -
Thomas Carrie,
Yao GangQing,
O'Brien Kimberly,
Kerstetter Jane,
Insogna Karl
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.lb284
Subject(s) - dmt1 , gene isoform , brush border , messenger rna , downregulation and upregulation , chemistry , duodenum , iron homeostasis , absorption (acoustics) , endocrinology , medicine , dietary iron , homeostasis , gene expression , metabolism , biology , iron deficiency , biochemistry , transporter , gene , vesicle , physics , membrane , acoustics , anemia
Intestinal iron absorption is a critical regulator of whole body iron homeostasis. The D ivalent M etal T ransporter 1 (DMT1) is a nonheme iron importer found on the brush border membrane of enterocytes. Its genetic absence in experimental animals leads to markedly impaired intestinal iron absorption. Recent data from our laboratory demonstrate that increasing dietary protein in rats enhances intestinal iron absorption by 50%, and that this is associated with a 3.8‐fold induction in DMT1 mRNA expression. To determine whether dietary protein affects the expression of the isoform of DMT1 that includes an iron responsive element (IRE), isoform‐specific qPCR was performed using RNA isolated from the duodenum of rats consuming either a 20% (control) or 40% (high) protein diet for 1 wk. Rats on the 40% protein diet exhibited significantly greater DMT1A‐IRE mRNA expression compared to animals consuming the 20% protein diet (fold change: 2.8; p <0.01), while no significant change was observed in the level of expression of the DMT1A isoform that does not include an IRE. These findings indicate that duodenal DMT1A‐IRE is selectively and significantly upregulated in response to increasing dietary protein.