Molecular cloning and expression of canine prolactin gene.

We isolated canine prolactin cDNA from a dog pituitary cDNA library. The 930-bp nucleotide sequence covered the entire open reading frame encoding the putative 229 amino acids. It was located in chromosome 35, and had five exons. The amino acid sequence was highly homologous to the feline and porcine sequences. To generate recombinant canine prolactin, plasmids for full-length canine prolactin were constructed and transfected into the mammalian HEK293 cell line. The recombinant prolactin was secreted into the medium as an N-linked glycosylated (31 kDa) or non-glycosylated (27 kDa) protein. Western blotting revealed both of these bands were canine pituitary protein extracts.