Hirai T, Takikawa H, Kato Y
Department of Protein Chemistry, Gunma University, Japan.
Mol Cell Endocrinol. 1989 May;63(1-2):209-17. doi: 10.1016/0303-7207(89)90097-x.
cDNA clones encoding precursors of glycoprotein hormone common alpha-subunit (pre-alpha) and of thyroid stimulating hormone beta-subunit (pre-TSH beta) were isolated from a porcine anterior pituitary cDNA library using DNA probes, and the nucleotide sequences were determined. The nucleotide sequence of pre-alpha cDNA contained an entire coding region (360 bases) including 5' and 3' untranslated regions. The pre-alpha mRNA was about 900 bases long. The predicted amino acid sequence consisted of a signal peptide of 24 amino acid residues and a mature alpha-subunit protein of 96 residues. Six amino acid residues at the amino terminus of the predicted mature protein had not been found by direct amino acid sequencing of the purified protein. The nucleotide sequence of pre-TSH beta cDNA contained an entire coding region and a 3' untranslated region which has two polyadenylation signals. The length of the pre-TSH beta mRNA was about 500 bases long. The predicted amino acid sequence consisted of a signal peptide of 20 amino acid residues, a mature protein of 112 residues and an additional extension of six amino acid residues at the carboxyl terminus, which had not been found in the amino acid sequence of the purified protein. The coding sequences of the cDNAs showed high homologies with those of other mammalian species (84-93% for pre-alpha and 81-94% for pre-TSH beta). Comprehensive data of our serial molecular cloning for porcine glycoprotein hormones revealed low but significant homologies (34-40%) among three beta-subunits. Upon comparison of frequency of (U)n A sequence in 3' untranslated region, porcine pre-alpha and pre-TSH beta mRNAs were grouped into a moderate class of mRNA stability whereas porcine pre-FSH beta and pre-LH beta were grouped into unstable and stable classes, respectively.
使用DNA探针从猪垂体前叶cDNA文库中分离出编码糖蛋白激素共同α亚基前体（前α）和促甲状腺激素β亚基前体（前TSHβ）的cDNA克隆，并测定了核苷酸序列。前α cDNA的核苷酸序列包含一个完整的编码区（360个碱基），包括5'和3'非翻译区。前α mRNA约900个碱基长。预测的氨基酸序列由一个24个氨基酸残基的信号肽和一个96个残基的成熟α亚基蛋白组成。通过对纯化蛋白的直接氨基酸测序未发现预测成熟蛋白氨基末端的六个氨基酸残基。前TSHβ cDNA的核苷酸序列包含一个完整的编码区和一个具有两个聚腺苷酸化信号的3'非翻译区。前TSHβ mRNA的长度约为500个碱基长。预测的氨基酸序列由一个20个氨基酸残基的信号肽、一个112个残基的成熟蛋白和羧基末端额外的六个氨基酸残基延伸组成，在纯化蛋白的氨基酸序列中未发现该延伸。cDNA的编码序列与其他哺乳动物物种的编码序列具有高度同源性（前α为84 - 93%，前TSHβ为81 - 94%）。我们对猪糖蛋白激素的系列分子克隆的综合数据显示，三个β亚基之间的同源性较低但显著（34 - 40%）。通过比较3'非翻译区中（U）nA序列的频率，猪前α和前TSHβ mRNA被归为中等稳定性的mRNA类别，而猪前FSHβ和前LHβ分别被归为不稳定和稳定类别。
