Tissue-specific DNaseI hypersensitivity regions are located in the 5'-region of the rat preproenkephalin gene.
Extracellular stimuli affecting mechanisms of transcriptional control of the preproenkephalin gene link stimulus-secretion-synthesis coupling to transmitter phenotypic expression. In order to define distal and proximal genomic regions that might participate in transcriptionally active protein-DNA interactions, DNaseI hypersensitivity assays were conducted. Four DNaseI-hypersensitive regions were identified at -3000, -2500, -1800, and -200 base pairs (bp) relative to the somatic start site. The appearance of a site over the proximal promoter/enhancer region (-200 bp) is of interest since we and others have published a detailed footprint and functional analysis of this region using rat tissues. While liver (which does not express proenkephalin mRNA) displays essentially no hypersensitivity here, adrenal gland preparations show a strong signal and striatal tissue a significantly weaker signal. Cholinergic induction of proenkephalin mRNA was not associated with a change in hypersensitivity pattern. These data suggest that chromatin structure may have an influence on preproenkephalin transcriptional control and that cholinergic-inducible cis-acting DNA elements may reside within subdomains of at least these four hypersensitivity sites. Understanding the basis of this open chromatin structure should aid in identifying genomic mechanisms involved in tissue-specific expression and suggest avenues of future study.
Holloway
M P
MP
Department of Pediatrics, State University of New York, Stony Brook 11794-8111.
La Gamma
E F
EF
D000311:Adrenal Glands / Q000378:metabolism; D000818:Animals; D015139:Blotting, Southern; D003342:Corpus Striatum / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D004745:Enkephalins / Q000235:genetics*; D008099:Liver / Q000378:metabolism; D008297:Male; D011401:Promoter Regions, Genetic; D011498:Protein Precursors / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011950:Receptors, Cholinergic / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid
D004745:Enkephalins; D011498:Protein Precursors; D011950:Receptors, Cholinergic; C033660:preproenkephalin; D003850:Deoxyribonuclease I