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Published on: June 2, 2023
Cloning, sequencing, characterization, and expressions of divalent metal transporter one in the small intestine of
1Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100094, PR China.
Abstract:
Divalent metal transporter 1 (DMT1) is an electrogenic transporter of divalent Mn that is expressed at a high level on the brush-border membrane of enterocytes. This study is the first reported isolation of the 2 full-length cDNA sequences of the small intestinal DMT1 gene of broilers by rapid amplification of cDNA ends. The chicken DMT1 isoform I cDNA was 1,972 bp and contained a 1,695-bp open reading frame encoding a 564-amino acid protein, and the chicken DMT1 isoform II cDNA was 1,775 bp and contained a 1,593-bp open reading frame encoding a 530-amino acid protein. The 2 chicken DMT1 isoform transcripts differed in their 3'-translated regions and untranslated regions. The identities of the amino acid sequence deduced from the full-length cDNA sequence of the chicken DMT1 isoform I with DMT1 not containing the iron-responsive element of the mouse, rat, and human were 82, 82, and 80%, respectively. The identities of the amino acid sequence deduced from the full-length cDNA sequence of the chicken DMT1 isoform II with those of the mouse, rat, and human were 84, 84, and 83%, respectively. Analyses of hydrophobicity, transmembrane region, and signal peptides of DMT1 proteins deduced by nucleotide sequences suggested that chicken DMT1 isoforms are transmembrane proteins with several conserved peptide sequences, such as N-linked glycosylation signals (N-X-S/ T, where X designates any amino acid) and the consensus transport motif. The total mRNA levels of the 2 chicken DMT1 isoforms, the mRNA levels of chicken DMT1 isoform I, and the mRNA levels of chicken DMT1 isoform II in the duodenum and jejunum were higher (P<0.002) than that in the ileum by real-time reverse transcription PCR assay. There was no significant difference (P>0.26) between the duodenum and jejunum for the above 3 indices. The mRNA level of the chicken DMT1 isoform I was higher (P<0.001) than that of the chicken DMT1 isoform II in each small intestinal segment of Mn-deficient broilers.
