|Title||Regulation of Hox gene activity by transcriptional elongation in Drosophila.|
|Publication Type||Journal Article|
|Year of Publication||2009|
|Authors||Chopra, VS, Hong, J-W, Levine, M|
|Date Published||2009 Apr 28|
|Keywords||Animals, Body Patterning, Cyclin-Dependent Kinase 9, Drosophila melanogaster, Drosophila Proteins, Gene Expression Regulation, Developmental, Genes, Homeobox, Homeodomain Proteins, Mutation, Phenotype, Promoter Regions, Genetic, Transcription Factors, Transcription, Genetic, Transcriptional Elongation Factors, Wing|
Hox genes control the anterior-posterior patterning of most metazoan embryos. Their sequential expression is initially established by the segmentation gene cascade in the early Drosophila embryo . The maintenance of these patterns depends on the Polycomb group (PcG) and trithorax group (trxG) complexes during the remainder of the life cycle . We provide both genetic and molecular evidence that the Hox genes are subject to an additional tier of regulation, i.e., at the level of transcription elongation. Both Ultrabithorax (Ubx) and Abdominal-B (Abd-B) genes contain stalled or paused RNA polymerase II (Pol II) even when silent [3, 4]. The Pol II elongation factors Elongin-A and Cdk9 are essential for optimal Ubx and Abd-B expression. Mitotic recombination assays suggest that these elongation factors are also important for the regulation of Notch-, EGF-, and Dpp-signaling genes. Stalled Pol II persists in tissues where Ubx and Abd-B are silenced by the PcG complex. We propose that stalling fosters both the rapid induction and precise silencing of Hox gene expression during development.
|Alternate Journal||Curr. Biol.|