1. Effect of 5'-flanking sequence deletions on expression of the human insulin gene in transgenic mice.
- Author
-
Fromont-Racine M, Bucchini D, Madsen O, Desbois P, Linde S, Nielsen JH, Saulnier C, Ripoche MA, Jami J, and Pictet R
- Subjects
- Animals, C-Peptide metabolism, C-Peptide urine, Chromosome Deletion, Female, Gene Expression, Humans, Immunohistochemistry, Insulin metabolism, Male, Mice, Mice, Transgenic, Pancreas anatomy & histology, Pancreas metabolism, RNA, Messenger genetics, Insulin genetics
- Abstract
Expression of the human insulin gene was examined in transgenic mouse lines carrying the gene with various lengths of DNA sequences 5' to the transcription start site (+1). Expression of the transgene was demonstrated by 1) the presence of human C-peptide in urine, 2) the presence of specific transcripts in pancreas, but not in other tissues, 3) the specific immunofluorescence staining of pancreatic islets for human C-peptide, and 4) the synthesis and accumulation of human (pro)insulin in isolated islets. Deletions in the injected DNA fragment of sequences upstream from positions -353, -258, and -168 allowed correct initiation of the transcripts and cell specificity of expression, while quantitative expression gradually decreased. Deletion to -58 completely abolished the expression of the gene. The amount of human product that in mice harboring the longest fragment contributes up to 50% of the total insulin does not alter the normal proportion of mice insulins I and II. These results suggest that expression of the human insulin gene in vivo results from the cooperation of several cis-regulatory elements present in the various deleted fragments. With none of the deletions used, expression of the transgene was observed in cell types other than beta-islet cells.
- Published
- 1990
- Full Text
- View/download PDF