Functional analysis of DNA-elements involved in transcriptional control of the human glucose transporter 2 (GLUT 2) gene in the insulin-producing cell line beta TC-3.
The uptake of glucose into pancreatic beta cells as a 'non-rate-limiting-step' is guaranteed by the expression and action of the high-Km glucose transporter 2 (GLUT 2). This transporter is not saturated by physiological plasma glucose levels and hence functions as a "glucose sensor/glucoreceptor". Here we describe DNA-elements of the human GLUT 2 gene promoter which contribute to transcriptional control in the insulin-producing cell line beta TC-3. Nested 5'-as well as 3'-deletions of a DNA-fragment containing up to 1245 bp of the 5'-flanking region and up to 308 bp of the first exon of the human GLUT 2 gene were investigated for their ability to control the expression of a CAT reporter gene in beta TC-3 cells. For tissue-specific transcriptional control 5'-deletional analysis revealed that the region -220/+309 was sufficient. Truncation from the 3'-end from nucleotide +308 to +204 led to a threefold drop in CAT expression. In vitro DNase I footprinting analysis was performed to delineate cis-elements within the region -220/+1. Five specifically protected areas could be defined.
Leibiger
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Institute of Biochemistry, School of Medicine, University of Greifswald, Germany.
Leibiger
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D016475:3T3 Cells / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002478:Cells, Cultured; D004247:DNA / Q000032:analysis; D017931:DNA Primers / Q000737:chemistry; D004251:DNA Transposable Elements / Q000502:physiology*; D005786:Gene Expression Regulation; D005947:Glucose / Q000378:metabolism*; D051273:Glucose Transporter Type 2; D006801:Humans; D007328:Insulin / Q000096:biosynthesis*; D007515:Islets of Langerhans / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins / Q000096:biosynthesis / Q000235:genetics*; D014162:Transfection
D017931:DNA Primers; D004251:DNA Transposable Elements; D051273:Glucose Transporter Type 2; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D004247:DNA; D005947:Glucose