title: Ceratitis capitata transformer-2 gene is required to establish and maintain the autoregulation of Cctra, the master gene for female sex determination.
abstract: In Drosophila melanogaster, transformer-2 (TRA-2) which is a non-sex-specific auxiliary splicing factor, is required to promote female sexual differentiation by interaction with the female-specific TRA. The two proteins positively regulate the splicing of both doublesex (dsx) and fruitless (fru) pre-mRNAs, which in turn regulate phenotypic and behavioural sexual dimorphism. In the Mediterranean fruitfly Ceratitis capitata, the female-specific CcTRA is similarly required not only for Ccdsx splicing, but also to exert a novel autoregulatory function that consists of promoting female-specific splicing of Cctra pre-mRNA. This study reports the isolation and functional analysis of the C. capitata homologue of the Drosophila transformer-2 gene (Cctra-2). Transient RNAi against Cctra-2 during embryonic development causes the full sex reversal of XX flies in adult fertile pseudo-males, as well as changes in the splicing pattern of Cctra, Ccdsx and Ccfruitless (Ccfru). We propose that: 1) Cctra-2, as in Drosophila, is necessary for promoting Ccdsx and putative Ccfru pre-mRNA female-specific splicing and that 2) unlike in Drosophila, Cctra-2 appears to be necessary for establishing female sex determination in early XX embryos and for maintaining the positive feedback regulation of Cctra during development.
authors.affiliation: Department of Biological Sciences, Section of Genetics and Molecular Biology, University of Naples Federico II, Naples, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Salvemini
authors.forename: Mark
authors.initials: M
authors.lastname: Robertson
authors.forename: Benjamin
authors.initials: B
authors.lastname: Aronson
authors.forename: Peter
authors.initials: P
authors.lastname: Atkinson
authors.forename: Lino C
authors.initials: LC
authors.lastname: Polito
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Saccone
mesh_terms: D017398:Alternative Splicing / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D033622:Ceratitis capitata / Q000196:embryology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D049750:Genome, Insect / Q000235:genetics; D008297:Male; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D034622:RNA Interference; D016415:Sequence Alignment; D012730:Sex Chromosomes / Q000235:genetics; D019849:Sex Determination Processes; D012726:Sexual Behavior, Animal; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins