Specific transgene expression in mouse pancreatic β-cells under the control of the porcine insulin promoter

• Published in: Molecular and cellular endocrinology 2010-02, Vol.315 (1), p.219-224
• Main Authors: Grzech, Marjeta, Dahlhoff, Maik, Herbach, Nadja, Habermann, Felix A., Renner-Müller, Ingrid, Wanke, Rüdiger, Flaswinkel, Heinrich, Wolf, Eckhard, Schneider, Marlon R.
• Format: Article
• Language: English
• Subjects: Animals; Base Sequence; Betacellulin; Blood Glucose - metabolism; Cattle; EGFR; Gene Expression Regulation; Glucose tolerance test; Humans; Insulin - genetics; Insulin-Secreting Cells - cytology; Insulin-Secreting Cells - physiology; Intercellular Signaling Peptides and Proteins - genetics; Intercellular Signaling Peptides and Proteins - metabolism; Mice; Mice, Transgenic; Molecular Sequence Data; Phenotype; Porcine insulin promoter; Promoter Regions, Genetic; Rats; Swine; Tissue Distribution; Transgenes; Transgenic mice; Untranslated Regions - genetics
• ISSN: 0303-7207; 1872-8057; 0303-7207
• DOI: 10.1016/j.mce.2009.08.001

The availability of regulatory sequences directing tissue-specific expression of transgenes in genetically modified mice and large animals is a prerequisite for the development of adequate models for human diseases. The rat insulin 2 gene ( Ins2) promoter, widely used to achieve transgene expression in pancreatic β-cells of mice, also directs expression to extrapancreatic tissues and performs poorly in isolated pancreatic islets of human, mouse, and pig. To evaluate whether the full 5′ untranslated region (UTR) of the porcine insulin gene ( INS) confers robust and specific expression in β-cells we generated an expression cassette containing 1500 bp of the porcine INS 5′ UTR and the 3′ UTR of the bovine growth hormone gene ( GH). The cassette was designed to allow easy exchange of the sequences to be expressed and easy removal of the vector backbone from the expression cassette. To evaluate the properties of the cassette, we initially inserted a cDNA encoding human betacellulin, a growth factor known to affect structural and functional parameters of β-cells. After confirming the functionality and specificity of the construct in vitro, transgenic mouse lines were generated by pronuclear DNA microinjection. Using RT-PCR, immunohistochemistry and immunofluorescence, we show that transgenic mice expressed human betacellulin exclusively in β-cells. Confirming the proposed insulinotropic effect of betacellulin, transgenic mice showed improved glucose tolerance. We conclude that the newly designed expression cassette containing 1500 bp of the porcine insulin promoter 5′ UTR confers robust and specific transgene expression to β-cells in vitro and in transgenic mice.