title: Integrated analysis of miRNA and mRNA expression profiles in tilapia gonads at an early stage of sex differentiation.
abstract: MicroRNAs (miRNAs) represent a second regulatory network that has important effects on gene expression and protein translation during biological process. However, the possible role of miRNAs in the early stages of fish sex differentiation is not well understood. In this study, we carried an integrated analysis of miRNA and mRNA expression profiles to explore their possibly regulatory patterns at the critical stage of sex differentiation in tilapia.
  
  
  
  We identified 279 pre-miRNA genes in tilapia genome, which were highly conserved in other fish species. Based on small RNA library sequencing, we identified 635 mature miRNAs in tilapia gonads, in which 62 and 49 miRNAs showed higher expression in XX and XY gonads, respectively. The predicted targets of these sex-biased miRNAs (e.g., miR-9, miR-21, miR-30a, miR-96, miR-200b, miR-212 and miR-7977) included genes encoding key enzymes in steroidogenic pathways (Cyp11a1, Hsd3b, Cyp19a1a, Hsd11b) and key molecules involved in vertebrate sex differentiation (Foxl2, Amh, Star1, Sf1, Dmrt1, and Gsdf). These genes also showed sex-biased expression in tilapia gonads at 5 dah. Some miRNAs (e.g., miR-96 and miR-737) targeted multiple genes involved in steroid synthesis, suggesting a complex miRNA regulatory network during early sex differentiation in this fish.
  
  
  
  The sequence and expression patterns of most miRNAs in tilapia are conserved in fishes, indicating the basic functions of vertebrate miRNAs might share a common evolutionary origin. This comprehensive analysis of miRNA and mRNA at the early stage of molecular sex differentiation in tilapia XX and XY gonads lead to the discovery of differentially expressed miRNAs and their putative targets, which will facilitate studies of the regulatory network of molecular sex determination and differentiation in fishes.
authors.affiliation: Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, 400715, P. R. China.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Tao
authors.affiliation: Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, 400715, P. R. China.
authors.forename: Lina
authors.initials: L
authors.lastname: Sun
authors.affiliation: Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, 400715, P. R. China.
authors.forename: Hongjuan
authors.initials: H
authors.lastname: Shi
authors.affiliation: Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, 400715, P. R. China.
authors.forename: Yunying
authors.initials: Y
authors.lastname: Cheng
authors.affiliation: Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, 400715, P. R. China.
authors.forename: Dongneng
authors.initials: D
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, P. R. China.
authors.forename: Beide
authors.initials: B
authors.lastname: Fu
authors.affiliation: Department of Biology, University of Maryland, College Park, MD, USA.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Conte
authors.affiliation: Department of Biology, University of Maryland, College Park, MD, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Gammerdinger
authors.affiliation: Department of Biology, University of Maryland, College Park, MD, USA. tdk@umd.edu.
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Kocher
authors.affiliation: Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, 400715, P. R. China. wdeshou@swu.edu.cn.
authors.forename: Deshou
authors.initials: D
authors.lastname: Wang
mesh_terms: D000818:Animals; D001483:Base Sequence; D017124:Conserved Sequence; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods*; D018507:Gene Expression Regulation, Developmental; D053263:Gene Regulatory Networks; D006066:Gonads / Q000254:growth & development* / Q000378:metabolism; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D017423:Sequence Analysis, RNA / Q000379:methods*; D012733:Sex Differentiation; D017210:Tilapia / Q000235:genetics / Q000254:growth & development*
chemical_list: D035683:MicroRNAs; D012333:RNA, Messenger
keywords: Early sex differentiation; Tilapia; mRNA; miRNA