Project description:Precise gene expression is a fundamental aspect of organismal function and depends on the combinatorial interplay of transcription factors (TFs) with cis‐regulatory DNA elements. While much is known about TF function in general, our understanding of their cell type‐specific activities is still poor. To address how widely expressed transcriptional regulators modulate downstream gene activity with high cellular specificity, we have identified binding regions for the Hox TF Deformed (Dfd) in the Drosophila genome. Our analysis of architectural features within Hox cis‐regulatory response elements (HREs) shows that HRE structure is essential for cell type‐specific gene expression. We also find that Dfd and Ultrabithorax (Ubx), another Hox TF specifying different morphological traits, interact with non‐overlapping regions in vivo, despite their similar DNA binding preferences. While Dfd and Ubx HREs exhibit comparable design principles, their motif compositions and motif‐pair associations are distinct, explaining the highly selective interaction of these Hox proteins with the regulatory environment. Thus, our results uncover the regulatory code imprinted in Hox enhancers and elucidate the mechanisms underlying functional specificity of TFs in vivo.
Project description:The goal of this study is to identify co-expressed genes downstream of Atonal and Senseless. These gene lists are used as candidate target genes (technically: as foreground sets) in computational predictions of cis-regulatory elements using the cisTargetX method (http://med.kuleuven.be/cme-mg/lng/cisTargetX). Together, the gene expression results and cis-regulatory predictions, yield a gene regulatory network underlying the early events in retinal differentiation. Predicted cis-regulatory interactions have been validated extensively in vivo using enhancer reporter assays and genetic perturbations. Six samples were analyzed for Atonal gain-of-function (GOF) in the eye-antennal imaginal discs of third instar larvae of Drosophila melanogaster, namely three biological repeats for two different Gal4 drivers (Gal4/7 and AtoGal), crossed with UASato. Three samples were analyzed for Atonal loss-of-function (LOF) in the eye-antennal imaginal discs, namely three biological repeats of ato-/- larvae. Three samples were analyzed for Senseless GOF, namely three biological repeats of atoGal4 crossed with UASsens. Finally, eight control samples were analyzed, namely two biological repeats of four different lines (atoGal4, Gal4/7, UASato, and cantonS wild type).
Project description:We applied microfluidic multiplex PCR and deep sequencing (mmPCR-seq) to quantify RNA editing levels at targeted sites in Drosophila melanogaster, Drosophila sechellia and the species-specific alleles of their F1 hybrids to understand the contribution of cis and trans regulatory factors to regulating RNA editing levels.