Project description:Genome-wide identification of R-loops almost uniquely relies on antibody based pull-down, a method that shows sequence and structural biases. Here we describe a novel approach – DREAM-seq – centered around the use of endonuclease digestions. Unstimulated and stimulated B cells showed that R-loops are more widespread than anticipated, mostly covering all actively transcribed genes.
Project description:Mutations in the DREAM complex induce germline-like gene expression patterns including the increase of multiple mechanisms of DNA repair in the soma of Caenorhabditis elegans. This confers mutants of the DREAM complex resistance to a wide range of DNA damage types during development and aging.
Project description:DNA double-stranded breaks (DSBs) pose a significant threat to genomic integrity, and their generation during essential cellular processes like transcription remains poorly understood. In this study, we employed DRIP-seq and ChIP-seq to map the change in TOP1cc and R-loops after the depletion of TOP1 and R-loops, to comprehensively investigate the interplay between transcription, DSBs, Topoisomerase 1 (TOP1), and R-loops. Our findings revealed the presence of DSBs at highly expressed genes enriched with TOP1 and R-loops, indicating their crucial involvement in transcription-associated genomic instability. Depletion of R-loops and TOP1 specifically reduced DSBs at highly expressed genes, uncovering their pivotal roles in transcriptional DSB formation. By elucidating the intricate interplay between TOP1cc trapping, R-loops, and DSBs, our study provides novel insights into the mechanisms underlying transcription-associated genomic instability. Moreover, we establish a link between transcriptional DSBs and early molecular changes driving cancer development. Notably, our study highlights the distinct etiology and molecular characteristics of driver mutations compared to passenger mutations, shedding light on the potential for targeted therapeutic strategies. Overall, these findings deepen our understanding of the regulatory mechanisms governing DSBs in hypertranscribed genes associated with carcinogenesis, opening avenues for future research and therapeutic interventions.
Project description:Expression of DREAM in dorsal root ganglia and spinal cord is related to endogenous control mechanisms of acute and chronic pain. In primary sensory trigeminal neurons high levels of endogenous DREAM protein are preferentially localized in the nucleus, suggesting a major transcriptional role. Here, we show that DREAM participates in the control of trigeminal pain perception through the regulation of prodynorphin and BDNF. Furthermore, genome-wide analysis of trigeminal neurons in daDREAM transgenic mice revealed that cathepsin L (CTSL) and the monoglyceride lipase (MGLL) are new DREAM downstream targets and have a role in the regulation of trigeminal nociception.
Project description:It is generally assumed that all estrogen receptor positive (ER+) breast cancers proliferate in response to estrogen and therefore examples of estrogen-induced regression of ER+ cancers are paradoxical. This review reexamines the estrogen regression paradox for the Luminal A subtype of ER+ breast cancers. The proliferative response to estrogen is shown to depend on the level of ER. Mechanistically, a window of opportunity study of pre-operative estradiol suggested that with higher levels of ER, estradiol could activate the DREAM-MMB (Dimerization partner, Retinoblastoma-like proteins, E2F4, and MuvB – MYB-MuvB) pathway to decrease proliferation. The response of breast epithelium and the incidence of breast cancers during hormonal variations that occur during the menstrual cycle and at the menopausal transition respectively suggest that a single hormone, either estrogen, progesterone or androgen could activate the DREAM pathway leading to reversible cell cycle arrest. Conversely, the presence of two hormones, could switch the DREAM-MMB complex to a pro-proliferative pathway. Using publicly available data, we examine the gene expression changes after aromatase inhibitors and ICI 182,780 to provide support for the hypothesis. This review suggests that it might be possible to integrate all current hormonal therapies for Luminal A tumors within a single theoretical schema.
