Disconnected, a C2H2 Zinc Finger Protein, has a role in Appendage Formation and Gene Regulation in Drosophila.

Abstract

One the biggest questions in developmental biology is how the Hox proteins direct such complex target gene regulation given that they have very little target specificity. The Homeotic⁄Hox proteins are evolutionarily conserved proteins that specify segment identity by regulating segment-specific batteries of target genes. One possible way to increase transcription specificity is through the use of cofactors. This has lead to the extensive searches to identify potential Hox cofactors. Although several Hox cofactors have been identified, only Extradenticle has been well characterized. Previously, our lab identified paralogous redundant genes disconnected (disco) and disco-related (disco-r) as genetic cofactors for the Hox genes Deformed and Sex combs reduced that are required for proper Drosophila embryonic head patterning. disco and disco-r encode C2H2 zinc finger transcription factors that are conserved among edysozoa, lophotrochozoa, and some deuterosomes. Here, I present a molecular characterization of Disco as a transcription factor. I determined that Disco is able to bind to sequences that contain TGACA at the core in vitro. Furthermore, I characterized the interaction of Disco with the corepressor CtBP. I also examine the significance of certain amino acid differences in the DNA-binding domain between ecdysozoa⁄lophothrochozoa and deuterosomes, concluding that one cysteine is required for complete Disco function.

In addition to the molecular characterization, I also describe Disco's role during development of the adult Drosophila demonstrating that Disco is part of the appendage development network. This data is supported from studies in Tribolium castaneum done by Lisa Robertson and Nathaniel Grubbs.

Several redundant C2H2 zinc finger genes have been identified in Drosophila including disco and disco-r that have roles in segmental patterning. Based on this we undertook a genome wide study to identify other novel, redundant C2H2 zinc finger genes that also function during segmental patterning. The results of this study are presented including identification two genes, CG5249 and CG11798. Lastly, the appendix contains data from a microarray experiment that examined transcriptional changes due to ectopic activation of Disco.