A novel 25 bp tandem repeat within the human trefoil peptide gene TFF2 in 21q22.3: polymorphism and mammalian evolution.
Trefoil peptides belong to a family of small secretory proteins characterised by three intrachain disulfide bonds forming the trefoil motif (TFF-domain). They serve to maintain or repair the epithelial mucosa, and promote cell migration. They are predominantly found in gastrointestinal tissues, and are upregulated around areas of epithelial damage, and in meta- and neoplasia. The corresponding three genes are clustered in human 21q22.3. TFF2 is the only human one encoding two TFF-domains on separate exons. In between (intron 2), a novel 25 bp sequence is located that is tandemly repeated approximately 48 times, but is unique in the human genome. A diallelic polymorphism with a second allele comprising approximately 53 repeat units is present among individuals. Both alleles were cloned on BAC recombinants. In Caucasians (n = 78) the allele frequencies found are 0.85 and 0.15, respectively, representing a frequency of heterozygosity of 26%. Ape and monkey species exhibit homologous repeats of shorter total array length, whereas none is found in other mammals.
Department of Anthropology and Human Genetics, University of Tübingen, Germany.
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Kayademir
E dos S
Edos S
Silva
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Pusch
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Beck
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JC
Machado
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Gött
D000483:Alleles; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D002891:Chromosomes, Human, Pair 21; D003001:Cloning, Molecular; D004247:DNA; D005787:Gene Frequency; D006133:Growth Substances / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D009077:Mucins; D005810:Multigene Family; D009124:Muscle Proteins; D009479:Neuropeptides; D010455:Peptides / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D020080:Tandem Repeat Sequences; D000071164:Trefoil Factor-2; D000071165:Trefoil Factor-3; D044465:White People / Q000235:genetics
D006133:Growth Substances; D009077:Mucins; D009124:Muscle Proteins; D009479:Neuropeptides; D010455:Peptides; C000604007:TFF2 protein, human; C099037:TFF3 protein, rat; C000604008:Tff2 protein, rat; D000071164:Trefoil Factor-2; D000071165:Trefoil Factor-3; D004247:DNA