title: Differential regulation of mesodermal gene expression by Drosophila cell type-specific Forkhead transcription factors.
abstract: A common theme in developmental biology is the repeated use of the same gene in diverse spatial and temporal domains, a process that generally involves transcriptional regulation mediated by multiple separate enhancers, each with its own arrangement of transcription factor (TF)-binding sites and associated activities. Here, by contrast, we show that the expression of the Drosophila Nidogen (Ndg) gene at different embryonic stages and in four mesodermal cell types is governed by the binding of multiple cell-specific Forkhead (Fkh) TFs - including Biniou (Bin), Checkpoint suppressor homologue (CHES-1-like) and Jumeau (Jumu) - to three functionally distinguishable Fkh-binding sites in the same enhancer. Whereas Bin activates the Ndg enhancer in the late visceral musculature, CHES-1-like cooperates with Jumu to repress this enhancer in the heart. CHES-1-like also represses the Ndg enhancer in a subset of somatic myoblasts prior to their fusion to form multinucleated myotubes. Moreover, different combinations of Fkh sites, corresponding to two different sequence specificities, mediate the particular functions of each TF. A genome-wide scan for the occurrence of both classes of Fkh domain recognition sites in association with binding sites for known cardiac TFs showed an enrichment of combinations containing the two Fkh motifs in putative enhancers found within the noncoding regions of genes having heart expression. Collectively, our results establish that different cell-specific members of a TF family regulate the activity of a single enhancer in distinct spatiotemporal domains, and demonstrate how individual binding motifs for a TF class can differentially influence gene expression.
authors.affiliation: Laboratory of Developmental Systems Biology, Genetics and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Xianmin
authors.initials: X
authors.lastname: Zhu
authors.forename: Shaad M
authors.initials: SM
authors.lastname: Ahmad
authors.forename: Anton
authors.initials: A
authors.lastname: Aboukhalil
authors.forename: Brian W
authors.initials: BW
authors.lastname: Busser
authors.forename: Yongsok
authors.initials: Y
authors.lastname: Kim
authors.forename: Terese R
authors.initials: TR
authors.lastname: Tansey
authors.forename: Adrian
authors.initials: A
authors.lastname: Haimovich
authors.forename: Neal
authors.initials: N
authors.lastname: Jeffries
authors.forename: Martha L
authors.initials: ML
authors.lastname: Bulyk
authors.forename: Alan M
authors.initials: AM
authors.lastname: Michelson
mesh_terms: D000465:Algorithms; D000483:Alleles; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D004331:Drosophila melanogaster; D004742:Enhancer Elements, Genetic; D051858:Forkhead Transcription Factors / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D008648:Mesoderm / Q000378:metabolism*; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D034622:RNA Interference; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
chemical_list: D051858:Forkhead Transcription Factors