ABSTRACT

Opioid peptide genes produce mRNAs for precursor proteins which are processed at specific punctuation points by selective proteases. The biological activity of opioids is manifested by these smaller peptide fragments which are released from the cell through secretory vesicles. In general, the regulation of opioid peptide genes occurs at four discrete biosynthetic levels: 1) transcriptional-regulation of the gene; 2) post-transcriptional-regulation of the mRNA; 3) post-translational-regulation of the precursor protein; and 4) release-secretion regulation. The mechanisms that regulate transcription of the proenkephalin gene at the first level of control will be examined in considerable detail.