title: Evolution of Fish Let-7 MicroRNAs and Their Expression Correlated to Growth Development in Blunt Snout Bream.
abstract: The lethal-7 (let-7) miRNA, known as one of the first founding miRNAs, is present in multiple copies in a genome and has diverse functions in animals. In this study, comparative genomic analysis oflet-7miRNAs members in fish species indicated thatlet-7miRNA is a sequence conserved family in fish, while different species have the variable gene copy numbers. Among the ten members including let-7a/b/c/d/e/f/g/h/i/j, the let-7a precursor sequence was more similar to ancestral sequences, whereas otherlet-7miRNA members were separate from the late differentiation of let-7a. The mostly predicted target genes oflet-7miRNAs are involved in biological process, especially developmental process and growth through Gene Ontology (GO) enrichment analysis. In order to identify the possible different functions of these ten miRNAs in fish growth development, their expression levels were quantified in adult males and females ofMegalobrama amblycephala, as well as in 3-, 6-, and 12-months-old individuals with relatively slow- and fast-growth rates. These ten miRNAs had similar tissue expression patterns between males and females, with higher expression levels in the brain and pituitary than that in other tissues (p< 0.05). Among these miRNAs, the relative expression level oflet-7awas the highest among almost all the tested tissues, followed bylet-7b,let-7dandlet-7c/e/f/g/h/i/j. As to the groups with different growth rates, the expression levels oflet-7miRNAs in pituitary and brain from the slow-growth group were always significantly higher than that in the fast-growth group (p< 0.05). These results suggest thatlet-7miRNA members could play an important role in the regulation of growth development inM. amblycephalathrough negatively regulating expression of their target genes.
authors.affiliation: College of Fisheries, Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education/Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China. zhaobowen@webmail.hzau.edu.cn.|Collaborative Innovation Center for Healthy Freshwater Aquaculture of Hubei Province, Hubei Provincial Engineering Laboratory for Pond Aquaculture, Wuhan 430070, China. zhaobowen@webmail.hzau.edu.cn.
authors.forename: Bo-Wen
authors.initials: BW
authors.lastname: Zhao
authors.affiliation: College of Fisheries, Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education/Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China. 15171617087@163.com.|Collaborative Innovation Center for Healthy Freshwater Aquaculture of Hubei Province, Hubei Provincial Engineering Laboratory for Pond Aquaculture, Wuhan 430070, China. 15171617087@163.com.
authors.forename: Lai-Fang
authors.initials: LF
authors.lastname: Zhou
authors.affiliation: Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616, USA. idrliu@ucdavis.edu.
authors.forename: Yu-Long
authors.initials: YL
authors.lastname: Liu
authors.affiliation: College of Fisheries, Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education/Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China. wansm0517@gmail.com.|Collaborative Innovation Center for Healthy Freshwater Aquaculture of Hubei Province, Hubei Provincial Engineering Laboratory for Pond Aquaculture, Wuhan 430070, China. wansm0517@gmail.com.
authors.forename: Shi-Ming
authors.initials: SM
authors.lastname: Wan
authors.affiliation: College of Fisheries, Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education/Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China. gaozexia@hotmail.com.|Collaborative Innovation Center for Healthy Freshwater Aquaculture of Hubei Province, Hubei Provincial Engineering Laboratory for Pond Aquaculture, Wuhan 430070, China. gaozexia@hotmail.com.
authors.forename: Ze-Xia
authors.initials: ZX
authors.lastname: Gao
mesh_terms: D000818:Animals; D049628:Body Size; D001921:Brain / Q000378:metabolism; D003530:Cyprinidae / Q000235:genetics* / Q000254:growth & development; D019143:Evolution, Molecular; D005260:Female; D018507:Gene Expression Regulation, Developmental; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D010902:Pituitary Gland / Q000378:metabolism
chemical_list: D035683:MicroRNAs
keywords: Megalobrama amblycephala; evolution; expression; fish; growth development; let-7 miRNA