Identification, expression and regulation of amphioxus G6Pase gene with an emphasis on origin of liver.
Vertebrate glucose-6-phosphatase (G6Pase) consists of three isozymes: G6Pase-I, G6Pase-II and G6Pase-III. Despite extensive study on G6Pases in vertebrates, information regarding expression and regulation of G6Pase genes is rather limited in invertebrates. Here we report the identification of G6Pase gene in amphioxus Branchiostoma japonicum, which is abundantly expressed in the digestive diverticulum and ovary in a tissue-specific manner. The phylogenetic and genomic structure analyses reveal that amphioxus G6Pase bears close resemblance to vertebrate G6Pase-III and represents the archetype of vertebrate G6Pase from which the vertebrate G6Pase isoforms may be originated by 2 rounds of genome duplication during vertebrate evolution. We also demonstrate that GH treatment induces a closely similar expression pattern and trend of g6pases in both zebrafish and amphioxus, and that G6Pase activity in amphioxus digestive diverticulum is subjected to regulation of feeding and fasting as observed in vertebrates. Collectively, all these provide functional evidences supporting the notion that the digestive diverticulum is the liver homologue playing a key role in maintaining the glucose homeostasis in amphioxus.
Laboratory for Evolution & Development, Institute of Evolution & Marine Biodiversity and Department of Marine Biology, Ocean University of China, Qingdao 266003, China.
Yu
Y
Wang
Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
Hui
H
Wang
Laboratory for Evolution & Development, Institute of Evolution & Marine Biodiversity and Department of Marine Biology, Ocean University of China, Qingdao 266003, China.
Mengyang
M
Li
Laboratory for Evolution & Development, Institute of Evolution & Marine Biodiversity and Department of Marine Biology, Ocean University of China, Qingdao 266003, China.
Zhan
Z
Gao
Laboratory for Evolution & Development, Institute of Evolution & Marine Biodiversity and Department of Marine Biology, Ocean University of China, Qingdao 266003, China. Electronic address: sczhang@ouc.edu.cn.
Shicui
S
Zhang
D000818:Animals; D005075:Biological Evolution; D005786:Gene Expression Regulation; D016678:Genome; D023281:Genomics; D005952:Glucose-6-Phosphatase / Q000235:genetics* / Q000378:metabolism*; D064175:Lancelets / Q000201:enzymology* / Q000235:genetics; D008099:Liver / Q000201:enzymology*; D010802:Phylogeny; D020033:Protein Isoforms / Q000378:metabolism; D015027:Zebrafish / Q000235:genetics / Q000378:metabolism*
D020033:Protein Isoforms; D005952:Glucose-6-Phosphatase
Amphioxus; Digestive diverticulum; Glucose homeostasis; Glucose-6-phosphatase; Liver; Zebrafish