title: The GATA factor Serpent cross-regulates lozenge and u-shaped expression during Drosophila blood cell development.
abstract: The Drosophila GATA factor Serpent interacts with the RUNX factor Lozenge to activate the crystal cell program, whereas SerpentNC binds the Friend of GATA protein U-shaped to limit crystal cell production. Here, we identified a lozenge minimal hematopoietic cis-regulatory module and showed that lozenge-lacZ reporter-gene expression was autoregulated by Serpent and Lozenge. We also showed that upregulation of u-shaped was delayed until after lozenge activation, consistent with our previous results that showed u-shaped expression in the crystal cell lineage is dependent on both Serpent and Lozenge. Together, these observations describe a feed forward regulatory motif, which controls the temporal expression of u-shaped. Finally, we showed that lozenge reporter-gene activity increased in a u-shaped mutant background and that forced expression of SerpentNC with U-shaped blocked lozenge- and u-shaped-lacZ reporter-gene activity. This is the first demonstration of GATA:FOG regulation of Runx and Fog gene expression. Moreover, these results identify components of a Serpent cross-regulatory sub-circuit that can modulate lozenge expression. Based on the sub-circuit design and the combinatorial control of crystal cell production, we present a model for the specification of a dynamic bi-potential regulatory state that contributes to the selection between a Lozenge-positive and Lozenge-negative state.
authors.affiliation: Center for Vascular and Inflammatory Diseases, Department of Pathology, University of Maryland, School of Medicine, 800 W. Baltimore Street, Room 215, Baltimore, MD 21201, USA.
authors.forename: Selen
authors.initials: S
authors.lastname: Muratoglu
authors.forename: Barry
authors.initials: B
authors.lastname: Hough
authors.forename: Soe T
authors.initials: ST
authors.lastname: Mon
authors.forename: Nancy
authors.initials: N
authors.lastname: Fossett
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D019070:Cell Lineage; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology; D050980:GATA Transcription Factors / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D006410:Hematopoiesis / Q000502:physiology*; D006434:Hemocytes / Q000166:cytology / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D050980:GATA Transcription Factors; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C099964:lz protein, Drosophila; C103965:srp protein, Drosophila; C109258:ush protein, Drosophila