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Insulin gene expression in nonexpressing cells appears to be regulated by multiple distinct negative-acting control
S R Cordle1, J Whelan, E Henderson
1Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee 37232.
Molecular and Cellular Biology
|May 1, 1991
Summary
Researchers identified a negative regulatory region in the insulin gene enhancer. Deleting this region allowed insulin gene transcription in non-beta cells, revealing mechanisms of cell-type-specific gene expression.
Area of Science:
- Molecular Biology
- Genetics
- Endocrinology
Background:
- Selective transcription of the insulin gene in pancreatic beta cells is crucial for glucose homeostasis.
- Insulin gene expression is regulated by enhancer elements interacting with cellular factors.
Purpose of the Study:
- To investigate the regulatory elements within the insulin gene enhancer.
- To identify factors controlling cell-type-specific insulin gene transcription.
Main Methods:
- Analysis of 5' deletions within the insulin gene enhancer.
- Assessing transcription in insulin-producing and non-insulin-producing cells.
- Investigating the binding of cellular factors to specific DNA sequences.
Main Results:
- A negative control region was identified between nucleotides -217 and -197 of the insulin enhancer.
- Deletion of this region resulted in transcription in non-insulin-producing cells, even with the insulin control element (ICE) intact.
- A ubiquitously distributed factor binding upstream of the ICE (-110 to -100) was implicated in this derepression.
Conclusions:
- The identified negative regulatory region plays a role in restricting insulin gene transcription to pancreatic beta cells.
- Understanding these regulatory mechanisms is key to comprehending cell-type-specific gene expression.
- These findings contribute to the broader understanding of transcriptional regulation in development and disease.