Xol-1, the master sex-switch gene in C. elegans, is a transcriptional target of the terminal sex-determining factor TRA-1

Balázs Hargitai, Vera Kutnyánszky, Timothy A. Blauwkamp, Attila Steták, Györgyi Csankovszki, Krisztina Takács-Vellai, Tibor Vellai

Research output: Contribution to journalArticle

17 Citations (Scopus)


In the nematode Caenorhabditis elegans, sex is determined by the ratio of X chromosomes to sets of autosomes: XX animals (2X:2A=1.0) develop as hermaphrodites and XO animals (1X:2A.0.5) develop as males. TRA-1, the worm ortholog of Drosophila Cubitus interruptus and mammalian Gli (Glioma-associated homolog) proteins, is the terminal transcription factor of the C. elegans sex-determination pathway, which specifies hermaphrodite fate by repressing male-specific genes. Here we identify a consensus TRA-1 binding site in the regulatory region of xol-1, the master switch gene controlling sex determination and dosage compensation. xol-1 is normally expressed in males, where it promotes male development and prevents dosage compensation. We show that TRA-1 binds to the consensus site in the xol-1 promoter in vitro and inhibits the expression of xol-1 in XX animals in vivo. Furthermore, inactivation of tra-1 enhances, whereas hyperactivation of tra-1 suppresses, lethality in animals with elevated xol-1 activity. These data imply the existence of a regulatory feedback loop within the C. elegans sex-determination and dosage-compensation cascade that ensures the accurate dose of X-linked genes in cells destined to adopt hermaphrodite fate.

Original languageEnglish
Pages (from-to)3881-3887
Number of pages7
Issue number23
Publication statusPublished - Sep 25 2009



  • Caenorhabditis elegans
  • Chromatin
  • Dosage compensation
  • Sex determination
  • TRA-1/Gli/ Ci
  • Xol-1

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology

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