Reduced expression of a naturally deleted form of human proopiomelanocortin complementary deoxyribonucleic acid after transfection into Chinese hamster ovary cells.

Department of Biochemistry and Physiology, University of Reading, Whiteknights, United Kingdom.

POMC is the precursor molecule for a number of hormones, ACTH, MSH, and beta-endorphin. The human genomic sequence has been elucidated, but to date the complete human complementary DNA (cDNA) sequence has not been published. Here we report the cloning and expression of human POMC cDNA from the anterior pituitary gland. Two forms of POMC cDNA have been identified; one sequence agrees with the cDNA sequence predicted from the published genomic sequence, and the second is a variant with a 9-base pair deletion (corresponding to the loss of three amino acids, Ser-Ser-Gly, between residues 67-73). Both POMC cDNA sequences have been expressed in Chinese hamster ovary cells. A significant difference was observed between the levels of expression in the cells and the amount secreted into the media of the two protein precursor molecules. The expression of the deleted variant in the cells was 16.4 +/- 0.9% of the level of normal POMC (P < 0.001), and in the media the deleted variant was 22.4 +/- 2.2% of the level of normal POMC (P < 0.001).

PMID: 7828531 [PubMed - indexed for MEDLINE]