title: Insulin-like growth factor I (IGF-I) in Chinese alligator, Alligator sinensis: Molecular characterization, tissue distribution and mRNA expression changes during the active and hibernating periods.
abstract: The Chinese alligator Alligator sinensis is an endangered species endemic to China, up to date, little is known about the regulation of its growth and development. Insulin-like growth factor I (IGF-I) plays a vital role in regulating vertebrate growth and development. In this study, the full-length cDNA of IGF-I in Chinese alligator (caIGF-I) was obtained for the first time, it contains 890-bp nucleotides encoding a 153-amino acid precursor, the mature caIGF-I consists of 70 amino acids by cleaving the signal peptide and C-terminal extension (E domain). The caIGF-I contains all the features of IGF-I peptide with B, C, A, and D domains and the six conservative cysteine residues involved in the stable tertiary structure. Multiple alignment analysis showed that the amino acid sequence of caIGF-I shares high identity with American alligator Alligator mississippiensis (100%) and birds (95-97%). Phylogenetic tree analysis of the IGF-I amino acid sequences indicated that alligators cluster into the bird branch. Real-time quantitative PCR technique showed that caIGF-I is widely expressed in all the examined tissues with the highest expression level in liver, higher in pancreas and oviduct while lower in heart, spleen, lung, kidney, stomach, intestines, ovary and muscles. During hibernation, the caIGF-I expression level decreased significantly in liver, pancreas, oviduct and kidney, while did not significantly change in heart, spleen, lung, stomach, small intestine, ovary and muscles. The mRNA expression changes during the two periods implicate that caIGF-I might play an important role in the regulation of feeding and growth in the Chinese alligator.
authors.affiliation: Key Laboratory for Conservation and Use of Important Biological Resources of Anhui Province, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Key Laboratory for Conservation and Use of Important Biological Resources of Anhui Province, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China. Electronic address: szzhang@mail.ahnu.edu.cn.
authors.forename: Shengzhou
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Key Laboratory for Conservation and Use of Important Biological Resources of Anhui Province, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Key Laboratory for Conservation and Use of Important Biological Resources of Anhui Province, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Alligator Research Center of Anhui Province, Xuanzhou 242000, China.
authors.forename: Yongkang
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Key Laboratory for Conservation and Use of Important Biological Resources of Anhui Province, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China.
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Wu
mesh_terms: D000489:Alligators and Crocodiles / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002681:China; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism*; D010053:Ovary / Q000378:metabolism; D010057:Oviducts / Q000378:metabolism; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics; D014018:Tissue Distribution
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I
keywords: Chinese alligator; Gene expression; Hibernation; IGF-I; Molecular clone