Complete structure of the porcine pro-opiomelanocortin mRNA derived from the nucleotide sequence of doned cDNA

Abstract
Polyadeny lated RNA Isolated from porcine pituitary neurolntermediate lobes was used to construct a cDNA library. The library was screened with a rat genomic DNA fragment specific for pro-opiomelanocortin sequences. Two positive clones, pJA-19 and pJA-20,containing respectively 850 bp and 550 bp were characterized. Sequence analysis of the cDNA Inserts revealed the complete structure of the porcine pro-opiomelanocortIn mRNA. This mRNA would include 129 5'-untranslated nucleotides, 801 nucleotides coding for the 267 amino acids precursor and 162 3'-untranslated nucleotides. Comparison with pro-opiomelanocortIn mRNA sequences from other species shows regions of high homology not only In the coding sequences but also In the 51 untranslated region where the first 50 nucleotides are over 60% purines.