title: DExD/H-box RNA helicase genes are differentially expressed between males and females during the critical period of male sex differentiation in channel catfish.
abstract: DExD/H-box RNA helicases are motor proteins participating in nearly all aspects of cellular processes, especially in RNA metabolism. In this study, a total of 54 DExD/H-box RNA helicase genes including 37 DDX (DEAD-box) and 17 DHX (DEAH-box) genes were characterized in channel catfish (Ictalurus punctatus), and annotated through phylogenetic and syntenic analyses. All the catfish RNA helicases contained conserved helicase signature motifs, demonstrating that the RNA helicase gene family was highly conserved. Analysis of the relative rates of synonymous (dS) and nonsynonymous (dN) substitutions revealed that the RNA helicase genes were subjected to strong negative (purifying) selection. Meta-analysis was conducted to determine expression of the RNA helicase genes during the critical period (90-110days post-fertilization, dpf) of male gonad differentiation. At 90dpf, 24 RNA helicase genes were highly differentially expressed in the gonad tissues between the males and females; similarly, 24 and 18 RNA helicase genes were found highly differentially expressed in the gonad tissues between the males and females at 100 and 110dpf, respectively (p<0.01). In general, the vast majority of the RNA helicase genes (31) were expressed at higher levels in females than in males. In the male gonad, a set of 8 RNA helicases were expressed at a significantly higher level at 110dpf than at 90dpf. These findings suggested that RNA helicases may play important roles in sex development and differentiation in teleosts.
authors.affiliation: The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA; College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei 430070, China.
authors.forename: Changxu
authors.initials: C
authors.lastname: Tian
authors.affiliation: The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA.
authors.forename: Suxu
authors.initials: S
authors.lastname: Tan
authors.affiliation: The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA.
authors.forename: Lisui
authors.initials: L
authors.lastname: Bao
authors.affiliation: The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA.
authors.forename: Qifan
authors.initials: Q
authors.lastname: Zeng
authors.affiliation: The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA.
authors.forename: Shikai
authors.initials: S
authors.lastname: Liu
authors.affiliation: The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA.
authors.forename: Yujia
authors.initials: Y
authors.lastname: Yang
authors.affiliation: The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA.
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Zhong
authors.affiliation: The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA. Electronic address: liuzhan@auburn.edu.
authors.forename: Zhanjiang
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D053487:DEAD-box RNA Helicases / Q000145:classification / Q000235:genetics*; D005260:Female; D007059:Ictaluridae / Q000235:genetics* / Q000254:growth & development; D008297:Male; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D012733:Sex Differentiation / Q000235:genetics*
chemical_list: D053487:DEAD-box RNA Helicases
keywords: Fish; Gonad development; RNA helicases; RNA-Seq; Sex differentiation