A bifunctional genetic regulatory element of the rat dopamine beta-hydroxylase gene influences cell type specificity and second messenger-mediated transcription

Dopamine beta-hydroxylase, the enzyme which converts dopamine to norepinephrine, is expressed in a cell type-restricted pattern in neuroendocrine tissue. A segment of the rat gene containing 395 bases of 5'-flanking sequence regulates expression of a reporter gene in a cell type-selective patte...

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Bibliographic Details
Published in:The Journal of biological chemistry 1992-09, Vol.267 (26), p.18821-18830
Main Authors: SHASKUS, J, GRECO, D, ASNANI, L. P, LEWIS, E. J
Format: Article
Language:English
Subjects:
Animals
Base Sequence
Biological and medical sciences
Cells, Cultured
DNA
Dopamine beta-Hydroxylase - genetics
Fundamental and applied biological sciences. Psychology
Gene Expression Regulation, Enzymologic
Genes. Genome
Molecular and cellular biology
Molecular genetics
Molecular Sequence Data
Promoter Regions, Genetic
Rats
RNA - metabolism
Second Messenger Systems
Substrate Specificity
Transcription, Genetic
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Summary:Dopamine beta-hydroxylase, the enzyme which converts dopamine to norepinephrine, is expressed in a cell type-restricted pattern in neuroendocrine tissue. A segment of the rat gene containing 395 bases of 5'-flanking sequence regulates expression of a reporter gene in a cell type-selective pattern in mammalian cell cultures. Using deletion mutants of the 5'-flanking sequence, we have identified a 30-base genetic regulatory element, designated DB1, which enhances transcription from a heterologous promoter 5-20-fold in neuroendocrine cell lines. DB1-specific DNA-protein complexes are found in nuclear extracts from all cell lines examined, but the migration pattern differs between cell lines. The 5'-flanking region of the dopamine beta-hydroxylase gene is also responsive to cyclic AMP and phorbol ester treatment of SHSY-5Y neuroblastoma cells. The simultaneous presence of both effectors results in synergistic increases in DBH1 mRNA and reporter gene activity. The second messenger regulatory element was localized to the region containing the DB1 element, and reporter plasmids containing multiple copies of the DB1 element are responsive to treatment with inducers. The results of this study identify a cis-acting regulatory element which influences both cell type selectivity and second messenger responsiveness of the rat dopamine beta-hydroxylase gene.
ISSN:0021-9258
1083-351X
DOI:10.1016/S0021-9258(19)37035-8