Effect of 5'-flanking sequence deletions on expression of the human insulin gene in transgenic mice

Mol Endocrinol. 1990 May;4(5):669-77. doi: 10.1210/mend-4-5-669.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • C-Peptide / metabolism
  • C-Peptide / urine
  • Chromosome Deletion
  • Female
  • Gene Expression
  • Humans
  • Immunohistochemistry
  • Insulin / genetics*
  • Insulin / metabolism
  • Male
  • Mice
  • Mice, Transgenic
  • Pancreas / anatomy & histology
  • Pancreas / metabolism
  • RNA, Messenger / genetics

Substances

  • C-Peptide
  • Insulin
  • RNA, Messenger