Control of μ opioid receptor expression by modification of cDNA 5'- and 3'-noncoding regions

Abstract Removal of a 712 base pair (bp) sequence following the coding region of a human μ opioid receptor (hμOR) cDNA unexpectedly increased expression of the receptor protein. A series of 3′-noncoding region deletion mutants revealed that at least three discrete regions following the stop codon influenced receptor expression levels. Deletion of the 205-bp 5′-noncoding region immediately preceding the Kozak sequence doubled receptor expression relative to wild type, and simultaneous deletion of 5′- and 3′-noncoding regions increased expression several fold. The hμOR noncoding regions may participate in a regulatory mechanism that controls the number of cell surface receptors.