| Abstract: | A number of cDNA clones corresponding to Xenopus POMC mRNA was isolated from a cDNA library constructed from Xenopus pituitary polyadenylated RNA. Characterization of the cDNA inserts revealed two groups of structurally different proopiomelanocortin mRNAs, indicating that two proopiomelanocortin genes are expressed to virtually the same level in Xenopus pituitary glands. From the mRNA structures the complete amino acid sequences of the two Xenopus preproopiomelanocortins could be deduced. Comparison with proopiomelanocortin mRNA and protein sequences from other species shows regions of high homology (including the portion of the prohormone located N-terminally of gamma-melanophore-stimulating hormone) and regions of extremely low homology (including the signal sequence). |
