The primary sex determination signal of Drosophila acts at the level of transcription

Cell. 1992 Mar 6;68(5):933-43. doi: 10.1016/0092-8674(92)90036-c.


For Drosophila, the choice between male and female development is made by the switch gene, Sxl, in response to the X:A ratio. Once Sxl is turned on in females, it actively maintains the determined state, independent of the X:A signal, by a positive autoregulatory feedback loop in which Sxl proteins direct the female-specific splicing of Sxl transcripts. In this paper we have investigated the mechanism controlling pathway initiation. Our results suggest a two-step model for the initial activation of Sxl in females. In the first step, a special class of Sxl mRNAs is expressed in female embryos from an early promoter that responds to the genes signaling the X:A ratio. The proteins produced from these early mRNAs then initiate the autoregulatory loop by directing the female-specific processing of transcripts from the late Sxl promoter.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Base Sequence
  • Drosophila melanogaster / embryology
  • Drosophila melanogaster / genetics*
  • Feedback
  • Gene Expression Regulation / genetics
  • Molecular Sequence Data
  • RNA Splicing
  • RNA, Messenger / analysis
  • Sequence Alignment
  • Sex Determination Analysis*
  • Trans-Activators
  • Transcription, Genetic


  • RNA, Messenger
  • Trans-Activators

Associated data

  • GENBANK/M84162
  • GENBANK/M84163
  • GENBANK/M84182
  • GENBANK/S72766
  • GENBANK/S72767
  • GENBANK/S72768
  • GENBANK/S72769
  • GENBANK/S72771
  • GENBANK/S88324
  • GENBANK/X63098