Nucleotide sequence of eCG alpha-subunit cDNA and its expression in the equine placenta

Equine chorionic gonadotropin (eCG) is a member of the glycoprotein family, which includes lutropin (LH), follitropin (FSH), and thyrotropin (TSH), all consisting of two noncovalently linked a-and β-subunits. In the present study, we determined the full length of the equine α-subunit cDNA sequence. mRNA was extracted from equine placenta on day 70 of gestation. The nucleotide sequence of the eCG a-subunit cDNA was amplified by PCR using mixed primers designed on the basis of the nucleotide sequence of human, rat and mouse a-subunits. Analysis of the nucleotide sequence revealed that the a-subunit amplified contained 387 bp which included the signal peptide (24 amino acids containing 4 amino acids expected) and the first 3 amino acid residues. When the expression of both subunit mRNAs in the equine placenta was compared by Northern blotting, the expression of the β-subunit mRNA was relatively greater than that of the a-subunit.