title: Aestivation induces changes in transcription and translation of coagulation factor II and fibrinogen gamma chain in the liver of the African lungfish Protopterus annectens.
abstract: This study aimed to sequence and characterize two pro-coagulant genes, coagulation factor II (f2) and fibrinogen gamma chain (fgg), from the liver of the African lungfish Protopterus annectens, and to determine their hepatic mRNA expression levels during three phases of aestivation. The protein abundance of F2 and Fgg in the liver and plasma was determined by immunoblotting. The results indicated that F2 and Fgg of P. annectens were phylogenetically closer to those of amphibians than those of teleosts. Three days of aestivation resulted in an up-regulation in the hepatic fgg mRNA expression level, while 6 days of aestivation led to a significant increase (3-fold) in the protein abundance of Fgg in the plasma. Hence, there could be an increase in the blood-clotting ability in P. annectens during the induction phase of aestivation. By contrast, the blood-clotting ability in P. annectens might be reduced in response to decreased blood flow and increased possibility of thrombosis during the maintenance phase of aestivation, as 6 months of aestivation led to significant decreases in mRNA expression levels of f2 and fgg in the liver. There could also be a decrease in the export of F2 and Fgg from the liver to the plasma so as to avert thrombosis. Three to 6 days after arousal from 6 months of aestivation, the protein abundance of F2 and Fgg recovered partially in the plasma of P. annectens; a complete recovery of the transcription and translation of f2/F2 in the liver might occur only after refeeding.
authors.affiliation: Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore.
authors.forename: Kum C
authors.initials: KC
authors.lastname: Hiong
authors.affiliation: Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore.
authors.forename: Xiang R
authors.initials: XR
authors.lastname: Tan
authors.affiliation: Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore.
authors.forename: Mel V
authors.initials: MV
authors.lastname: Boo
authors.affiliation: Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore.
authors.forename: Wai P
authors.initials: WP
authors.lastname: Wong
authors.affiliation: Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Republic of Singapore.
authors.forename: Shit F
authors.initials: SF
authors.lastname: Chew
authors.affiliation: Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore The Tropical Marine Science Institute, National University of Singapore, Kent Ridge, Singapore 119227, Republic of Singapore dbsipyk@nus.edu.sg.
authors.forename: Yuen K
authors.initials: YK
authors.lastname: Ip
mesh_terms: D000388:Air; D000818:Animals; D004956:Estivation / Q000235:genetics*; D005340:Fibrinogen / Q000235:genetics* / Q000378:metabolism; D005399:Fishes / Q000235:genetics* / Q000378:metabolism; D005618:Fresh Water; D005786:Gene Expression Regulation; D008099:Liver / Q000378:metabolism*; D010802:Phylogeny; D011516:Prothrombin / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; C027539:fibrinopeptides gamma; D011516:Prothrombin; D005340:Fibrinogen
keywords: Blood circulation; Fibrin; Haemostasis; Prothrombin; Thrombin; Thrombosis