title: Cloning and expression analysis of a transformer gene in Daphnia pulex during different reproduction stages.
abstract: The full-length cDNA of a transformer gene (Dptra) was cloned from the cladoceran Daphnia pulex using RACE. Dptra expression was assessed by qPCR and whole-mount in situ hybridization in different reproductive stages. The Dptra cDNA, 1652bp in length, has a 1158-bp open reading frame that encodes a 385 amino acid polypeptide containing one Sex determination protein N terminal (SDP_N) superfamily, eight putative phosphorylation sites, and an arginine-serine (RS)-rich domain at the N-terminus. Dptra showed 81%, 53%, 51% and 45% identity to orthologous genes in Daphnia magna, Apis mellifera, Apis cerana and Bombus terrestris, respectively. Phylogenetic analysis based on deduced amino acid sequences revealed that Dptra clustered in the hymenopteran clade and was most closely related to D. magna and A. mellifera. qPCR showed that Dptra expression increased significantly (P<0.05) in different reproductive stages in the following order: male, ephippial female, parthenogenetic female, resting egg and juvenile female. Dptra expression is significantly different between males and females and it is significantly greater in ephippial females and males than in parthenogenetic D. pulex (with summer eggs). Whole-mount in situ hybridization revealed that Dptra was expressed at different levels between males and females. In males, hybridization signals were found in the first antennae, second antennae and thoracic limb, whereas expression levels in the corresponding sites of parthenogenetic and ephippial females were relatively weak. This suggests that the Dptra gene plays significant roles in switching modes of reproduction and in sexual differentiation.
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo 315211, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Chen
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo 315211, China.
authors.forename: Shan-Liang
authors.initials: SL
authors.lastname: Xu
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo 315211, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo 315211, China.
authors.forename: Xiao-Ge
authors.initials: XG
authors.lastname: Guo
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo 315211, China.
authors.forename: Chun-Lin
authors.initials: CL
authors.lastname: Wang
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo 315211, China. Electronic address: wangdanli@nbu.edu.cn.
authors.forename: Dan-Li
authors.initials: DL
authors.lastname: Wang
authors.affiliation: School of Life Science, East China Normal University, Shanghai 200062, China. Electronic address: zhaoyunlong_ecnu@163.com.
authors.forename: Yun-Long
authors.initials: YL
authors.lastname: Zhao
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D003621:Daphnia / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D012098:Reproduction / Q000502:physiology
chemical_list: D018076:DNA, Complementary
keywords: Daphnia pulex; Gene expression; Reproduction switching, RNA whole-mount in situ hybridization; Transformer