title: Transcriptome Analysis of Honeybee (Apis Mellifera) Haploid and Diploid Embryos Reveals Early Zygotic Transcription during Cleavage.
abstract: In honeybees, the haplodiploid sex determination system promotes a unique embryogenesis process wherein females develop from fertilized eggs and males develop from unfertilized eggs. However, the developmental strategies of honeybees during early embryogenesis are virtually unknown. Similar to most animals, the honeybee oocytes are supplied with proteins and regulatory elements that support early embryogenesis. As the embryo develops, the zygotic genome is activated and zygotic products gradually replace the preloaded maternal material. The analysis of small RNA and mRNA libraries of mature oocytes and embryos originated from fertilized and unfertilized eggs has allowed us to explore the gene expression dynamics in the first steps of development and during the maternal-to-zygotic transition (MZT). We localized a short sequence motif identified as TAGteam motif and hypothesized to play a similar role in honeybees as in fruit flies, which includes the timing of early zygotic expression (MZT), a function sustained by the presence of the zelda ortholog, which is the main regulator of genome activation. Predicted microRNA (miRNA)-target interactions indicated that there were specific regulators of haploid and diploid embryonic development and an overlap of maternal and zygotic gene expression during the early steps of embryogenesis. Although a number of functions are highly conserved during the early steps of honeybee embryogenesis, the results showed that zygotic genome activation occurs earlier in honeybees than in Drosophila based on the presence of three primary miRNAs (pri-miRNAs) (ame-mir-375, ame-mir-34 and ame-mir-263b) during the cleavage stage in haploid and diploid embryonic development.
authors.affiliation: Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil.
authors.forename: Camilla Valente
authors.initials: CV
authors.lastname: Pires
authors.affiliation: Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil.
authors.forename: Flávia Cristina de Paula
authors.initials: FC
authors.lastname: Freitas
authors.affiliation: The University of Queensland, Diamantina Institute, Translational Research Institute, Brisbane, Australia.
authors.forename: Alexandre S
authors.initials: AS
authors.lastname: Cristino
authors.affiliation: Genetics Otago and Gravida, the National Centre for Growth and Development, Biochemistry Department, University of Otago, Dunedin, New Zealand.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Dearden
authors.affiliation: Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil.
authors.forename: Zilá Luz Paulino
authors.initials: ZL
authors.lastname: Simões
mesh_terms: D000818:Animals; D001516:Bees / Q000235:genetics*; D004171:Diploidy; D004625:Embryo, Nonmammalian; D005260:Female; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D006238:Haploidy; D019476:Insect Proteins / Q000235:genetics*; D008297:Male
chemical_list: D019476:Insect Proteins