Project description:Epithelial organs maintain their integrity and prevent tumour initiation by actively removing defective cells, such as those that have lost apicobasal polarity. Here, we identify how transcription factors of two key signalling pathways – Jun-N-terminal kinase (JNK) and Hippo – regulate epithelial integrity by controlling transcription of an overlapping set of target genes. Targeted DamID experiments reveal that in proliferating cells of the Drosophila melanogaster eye, the AP-1 transcription factor Jun, and the Hippo pathway transcription regulators Yorkie and Scalloped bind to a common suite of target genes that regulate organ growth. In defective neoplastic cells, AP-1 transcription factors repress transcription of growth genes together with the CtBP co-repressor. If gene repression by AP-1/CtBP fails, neoplastic tumour growth ensues, driven by Yorkie/Scalloped. Thus, AP-1/CtBP eliminates defective cells and prevents tumour initiation by acting in parallel to Yorkie/Scalloped to repress expression of a shared transcriptome. These findings shed new light on the maintenance of epithelial integrity and tumour suppression.
Project description:Targeted DamID was performed to identify binding targets of P-element somatic inhinitor (Psi), Myc and RNA Polymerase (using the RpII18 subunit common to all 3 polymerases). Scalloped(sd)-GAL4 was used to restrict expression to the wing disc.
Project description:Tree ring features are affected by environmental factors and therefore are the basis for dendrochronological studies to reconstruct past environmental conditions. Oak wood often provides the data for these studies because of the durability particularly of oak heartwood and, hence the availability of samples spanning long time periods of the distant past. Wood formation is regulated in part by epigenetic mechanisms such as DNA methylation. Studies in the methylation state of DNA preserved in oak heartwood thus could identify epigenetic tree ring features informing on past environmental conditions. We investigated the feasibility of such studies using heartwood samples core-drilled from the trunks of standing oak trees spanning the AD 1776-2014. Heartwood contains little DNA, and large amounts of phenolic compounds known to hinder the preparation of high-throughput sequencing libraries. We sequenced whole-genome and DNA methylome libraries for oak heartwood up to 100 and 50 years of age, respectively. However, only 56 genomic regions with sufficient coverage for quantitative methylation analysis were identified, suggesting that the high-throughput sequencing of DNA will be in principal feasible for wood formed <100 years ago is impeded by the reduction in library complexity caused by the bisulfite treatment used to generate the oak methylome.
Project description:Acute Oak Decline (AOD) is a decline-disease currently spreading in Britain, threatening oak trees. Here, we analyze and compare the proteomes of inner bark tissue sampled from oak stems of trees symptomatic with AOD and non-symptomatic trees.
Project description:Epithelial organs maintain their integrity and prevent tumour initiation by actively removing defective cells, such as those that have lost apicobasal polarity. Here, we identify how transcription factors of two key signalling pathways – Jun-N-terminal kinase (JNK) and Hippo – regulate epithelial integrity by controlling transcription of an overlapping set of target genes. Targeted DamID experiments reveal that in proliferating cells of the Drosophila melanogaster eye, the AP-1 transcription factor Jun, and the Hippo pathway transcription regulators Yorkie and Scalloped bind to a common suite of target genes that regulate organ growth. In defective neoplastic cells, AP-1 transcription factors repress transcription of growth genes together with the CtBP co-repressor. If gene repression by AP-1/CtBP fails, neoplastic tumour growth ensues, driven by Yorkie/Scalloped. Thus, AP-1/CtBP eliminates defective cells and prevents tumour initiation by acting in parallel to Yorkie/Scalloped to repress expression of a shared transcriptome. These findings shed new light on the maintenance of epithelial integrity and tumour suppression.