Dataset Information

Sex determination in honeybees: two separate mechanisms induce and maintain the female pathway.

ABSTRACT: Organisms have evolved a bewildering diversity of mechanisms to generate the two sexes. The honeybee (Apis mellifera) employs an interesting system in which sex is determined by heterozygosity at a single locus (the Sex Determination Locus) harbouring the complementary sex determiner (csd) gene. Bees heterozygous at Sex Determination Locus are females, whereas bees homozygous or hemizygous are males. Little is known, however, about the regulation that links sex determination to sexual differentiation. To investigate the control of sexual development in honeybees, we analyzed the functions and the regulatory interactions of genes involved in the sex determination pathway. We show that heterozygous csd is only required to induce the female pathway, while the feminizer (fem) gene maintains this decision throughout development. By RNAi induced knockdown we show that the fem gene is essential for entire female development and that the csd gene exclusively processes the heterozygous state. Fem activity is also required to maintain the female determined pathway throughout development, which we show by mosaic structures in fem-repressed intersexuals. We use expression of Fem protein in males to demonstrate that the female maintenance mechanism is controlled by a positive feedback splicing loop in which Fem proteins mediate their own synthesis by directing female fem mRNA splicing. The csd gene is only necessary to induce this positive feedback loop in early embryogenesis by directing splicing of fem mRNAs. Finally, fem also controls the splicing of Am-doublesex transcripts encoding conserved male- and female-specific transcription factors involved in sexual differentiation. Our findings reveal how the sex determination process is realized in honeybees differing from Drosophila melanogaster.

SUBMITTER: Gempe T

PROVIDER: S-EPMC2758576 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Sex determination in honeybees: two separate mechanisms induce and maintain the female pathway.

Gempe Tanja T Hasselmann Martin M Schiøtt Morten M Hause Gerd G Otte Marianne M Beye Martin M

PLoS biology 20091020 10

Organisms have evolved a bewildering diversity of mechanisms to generate the two sexes. The honeybee (Apis mellifera) employs an interesting system in which sex is determined by heterozygosity at a single locus (the Sex Determination Locus) harbouring the complementary sex determiner (csd) gene. Bees heterozygous at Sex Determination Locus are females, whereas bees homozygous or hemizygous are males. Little is known, however, about the regulation that links sex determination to sexual differenti ...[more]

PMID: 19841734

Similar Datasets

Project description:N6-methyladenosine (m6A) has recently emerged as a widespread and conserved RNA modification that modulates messenger RNA (mRNA) processing and activity. As most m6A studies have been conducted in cultured cells, we established Drosophila as a model system that combines molecular and genomic analyses of m6A with investigations of organismal biology. We first apply miCLIP sequencing to map m6A modifications at single-nucleotide resolution during Drosophila embryogenesis. We next characterize Drosophila components of the m6A "writer" methyltransferase complex [MTC factors, METTL3/IME4, METTL14, FL(2)D and Nito], and characterize m6A-binding properties of the YTH domain-containing proteins, YT521-B and CG6422. We complement this by generating a collection of mutants in m6A writer and reader components. While Drosophila orthologs of mammalian MTC factors that have additional roles in splicing are lethal, our mutants in METTL and YTH factors are viable but present specific developmental and behavioral defects. We note that several mammalian m6A factors were originally identified as Drosophila regulators of Sxl splicing, which generates the master determinant of female identity. While our mutants in dedicated writer and reader machinery are not required to accumulate Sxl protein in the ovary, maternal loss of m6A writers and readers collaborates with reduction of Sxl to induce female lethality. Our data indicate Sxl is directly regulated by the m6A pathway, since miCLIP data show Sxl is a substantial target of intronic m6A in early embryos, in addition to bearing exonic m6A. Consistent with this, female-specific Sxl splicing is defective in m6A pathway mutants. YT521-B appears to be the major effector of m6A for Sxl regulation, as it shows much stronger genetic interactions with Sxl than CG6422 and YT521-B overexpression can induce female-specific Sxl splicing. Overall, our transcriptomic and genetic toolkit for studying the m6A pathway in Drosophila reveals a major biological utilization in establishing sex-specific splicing.

Dataset Information

Sex determination in honeybees: two separate mechanisms induce and maintain the female pathway.

Publications

Sex determination in honeybees: two separate mechanisms induce and maintain the female pathway.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets