Cloning and Sequence Analysis of the Common α-Subunit Complementary Deoxyribonucleic Acid of Turkey Pituitary Glycoprotein Hormones ,

Abstract

Two cDNA clones of nearly full length that encode the turkey pituitary common α-subunit glycoprotein hormone have been isolated from a pituitary cDNA library and their nucleotide sequences have been determined. The longer α-subunit clone was 777 bp in length. It contained 88 bp of the 5′-untranslated region (UTR), an open reading frame of 360 bp (that encodes the turkey α-subunit 24 amino acid leader polypeptide fragment and 96 amino acid apoprotein), and a 312-bp 3′-UTR followed by a 17-bp poly A tract. When the nucleotide sequence of the turkey α-subunit was compared with the sequence of the chicken α-subunit clone, the coding region was greater than 98% homologous, but was only 69 to 76% homologous when compared with mammalian α-subunit sequences. Northern blot analysis showed an approximate 800 bp processed transcript that hybridized to the labeled turkey α-subunit cDNA. There was a greater than fourfold up-regulation of the steady-state levels of turkey α-subunit transcription when intact cultured pituitaries were treated with chicken gonadotropin-releasing hormone I.