Expression, crystallization and preliminary X-ray characterization of the Drosophila transcription factor Doublesex

Doublesex (DSX) is a transcription factor in Drosophila melanogaster that regulates somatic sexual differentiation. Homologues have been found in diverse metazoans, suggesting a conserved role in development. Here, the expression, purification and crystallization of a novel 63-amino-acid dimerization domain and selenomethionine analogue are described. Native crystals belong to space group P2(1)2(1)2(1) and diffract to a resolution of 1.6 A with synchrotron radiation. Selenomethionine-containing crystals provide anomalous dispersion for phasing.