ORIGINAL ARTICLE
Molecular characterization and tissue expression profiles of insulin-like
growth factor binding protein-1 (IGFBP-1) in Chinese alligator Alligator
sinensis during the active and hibernating periods
Mengyun Li
1
&
Ting Meng
1
&
Fei Peng
1
&
Shengzhou Zhang
1
&
Yongkang Zhou
2
&
Xiaobing Wu
1
Received: 27 February 2017 /Accepted: 29 January 2018 / Published online: 29 March 2018
#
Institute of Zoology, Slovak Academy of Sciences 2018
Abstract
The Chinese alligator Alligator sinensis (Fauvel, 1879) is an endangered species endemic to China. Up to this date, very little is
known about the regulation of its growth and development. Insulin-like growth factor binding protein-1 (IGFBP-1) plays
essential roles in regulating vertebrate growth and development by modulating IGFs action. In this study, we cloned the full-
length cDNA of Chinese alligator IGFBP-1 (caIGFBP-1) for the first time, which has an open reading frame (ORF) of 885-bp
nucleotides encoding a peptide of 294 amino acid residues. The caIGFBP-1 contains all features of IGFBP-1 peptide with the
conserved cysteine-rich N- and C-terminal domains and variable central L-domain. Multiple alignment analysis showed that
caIGFBP-1 shares high identity in amino acid sequence with the IGFBP-1 s of American alligator Alligator mississippiensis
(Daudin, 1802) (99.32%) and birds (66.32–74.53%). Phylogenetic tree analysis of IGFBP-1 amino acid sequences indicated that
alligators cluster into bird branch. The caIGFBP-1 is widely expressed in all the examined tissues, the expression level is highest
in liver, higher in kidney, moderate in pancreas, stomach, small intestine, and lower in ovary, muscle, lung, heart. During the
hibernating period, the expression level of caIGFBP-1 was significantly reduced in liver, kidney, stomach, pancreas and small
intestine, while did not significantly change in heart, lung, ovary and muscle. The caIGFBP-1 mRNA expression changes during
the active and hibernating periods, which coincides with that of Chinese alligator IGF, implicating that it might play important
roles in the IGF-mediated growth and development of Chinese alligator.
Keywords Chinese alligator
.
IGFBP-1
.
cDNA cloning
.
Gene expression
Introduction
The Chinese alligator Alligator sinensis (Fauvel, 1879) is the
most endangered member of crocodilian family in the world.
It was listed by the Chinese government as a Class I state-
protected species in 1972, meanwhile, nature reserves and
artificial farms of the Chinese alligator have been established
in Anhui and Zhejiang Provinces (Chen et al. 2003). In the
past two decades, the issues with artificial incubation and
breeding of the Chinese alligators have been successfully re-
solved, while the low reproductivity and slow growth rate of
this species is still the main problem faced in the artificial
breeding (Chen et al. 2003). Up to this date, very little is
known about the endocrine regulation of its growth and
development.
Insulin-like growth factor (IGF) system plays essential
roles in regulating the growth and development of vertebrates
(Moriyama et al. 2000; Ohlsson et al. 2009). This system
contains two ligands (IGF-I and IGF-II), two IGF receptors
(IGF-IR and IGF-IIR) and six IGF binding proteins (IGFBP-1
to −6) (Annunziata et al. 2011). IGFs exert their growth-
promoting effects through binding to cell-surface IGF recep-
tors, which is modulated by the effect of IGFBPs (Forbes et al.
2012). Among the six IGFBPs, IGFBP-1 is the first most
abundant form of IGFBPs in serum (Lee et al. 1993), which
* Shengzhou Zhang
szzhang@mail.ahnu.edu.cn
1
Key Laboratory for Conservation and Use of Important Biological
Resources of Anhui Province, College of Life Sciences, Anhui
Normal University, Wuhu, Anhui 241000, China
2
Alligator Research Center of Anhui Province, Xuancheng 242000,
China
Biologia (2018) 73:227–240
https://doi.org/10.2478/s11756-018-0028-3
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