中華鱉 (Pelodiscus sinensis)腦垂體糖蛋白激素cDNA序列mRNA生成調控之分析

Abstract

The pituitary glycoprotein hormones (thyrotropin, TSH; follitropin, FSH; lutropin, LH) are composed of two dissimilar subunit molecules, alpha and beta subunits are identical in a species; while beta subunits are specific and determine the hormone activity and species specificity. The comparative studies of cloning of cDNAs encoding these hormones and their gene regulations have been extensively conducted in mammals, birds, amphibian and fish. However, virtually no information has been available in reptiles. Reptiles occupy a key position in evolutionary history of vertebrates as the birds and mammals evolved from them. For better understanding the phylogenetic diversity and evolution of the cDNA nucleotide and peptide sequences of pituitary glycoprotein hormones in vertebrates, a study was conducted to clone the cDNAs of alpha subunit and the beta subunits of TSH, LH, and FSH of the Chinese soft-shell turtle, Pelodiscus sinensis, and to investigate the regulation of gene expression. The cDNAs were cloned by reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) methods. The cloned alpha cDNA consists of 670-bp nucleotides, including 71-bp 5’-untranslated region (UTR), 363-bp open reading frame, and 3’-UTR of 219-bp nucleotides, following by a 17-bp poly A trait. It encodes a 120 amino acid precursor molecule of alpha subunit with a putative signal peptide of 24 amino acids and a mature protein of 96 amino acids. The cloned TSH beta cDNA consists of 580-bp nucleotides, including 67-bp of 5’UTR, 402-bp of the open reading frame, and 97-bp of 3’UTR followed by a 14 bp poly A trait. It encodes a putative precursor protein of 133 amino acids with signal peptide of 19 amino acids and a mature protein of 114 amino acids. The cloned FSH