Project description:Transcription profiling by RNA-seq of Drosophila S2 cells after knock down of strongest cell cycle regulators to map their genome-wide transcriptional targets (155 assays). RNA samples used for this experiment are a subset of the 200 samples used in Affymetrix microarray experiment E-MTAB-453. E-MTAB-1648, E-MTAB-1364 and E-MTAB-453 are all data from: Bonke M, et al. (2013) Transcriptional networks controlling the cell cycle. G3 (Bethesda) 3, 75-90, PMID: 23316440.
Project description:In this work, we use RNAi and subsequent RNA isolation and Affymetrix Expression array analysis to map the genome-wide transcriptional targets of 107 of the strongest cell cycle regulators. Drosophila S2 cells were used with RNAi target gene knockdown compared to control (GFP dsRNA). RMA normalized data re-annotated using a custom CDF is available on the FTP site for this experiment. E-MTAB-1648, E-MTAB-1364 and E-MTAB-453 are all data from: Bonke M, et al. (2013) Transcriptional networks controlling the cell cycle. G3 (Bethesda) 3, 75-90, PMID: 23316440.
Project description:The family of apicomplexa-specific proteins with DNA binding AP2 domains (ApiAP2s) includes sequence-specific transcription factors that are key regulators of development in malaria parasites. However, functions for the majority of ApiAP2 genes remain unknown. Here, a systematic knockout screen in Plasmodium berghei identifies ten ApiAP2 genes essential for mosquito transmission, of which four are critical for the formation of infectious ookinetes and three for sporogony. We describe unexpected non-essential functions for AP2-O and AP2-SP proteins in blood stages and identify AP2-G2 as a universal repressor active in both, asexual and sexual stages. Comparative transcriptomics across mutants and developmental stages reveals clusters of co-regulated genes with shared cis elements in their promoters, whose expression can be controlled positively or negatively by different ApiAP2 gene deletions. We propose that stage-specific interactions between ApiAP2 proteins on partly overlapping sets of target genes generate the complex transcriptional network that controls the Plasmodium life cycle.
Project description:Our focus is to investigate the regulatory networks which are involved in the development and subsequent differentiation of haematopoietic stem and progenitor cells. The aim is to identify new targets and co-operative binding partners of established stem cell transcription factors as well as identifiying new important transcriptional regulators.
Project description:The core-promoter, a stretch of DNA surrounding the transcription-start-site (TSS), is a major integration-point for regulatory-signals controlling gene-transcription. Cellular-differentiation is marked by divergence in transcriptional-repertoire and cell- cycling behaviour between cells of different fates. The role promoter-associated gene- regulatory-networks play in development-associated transitions in cell-cycle- dynamics is poorly understood. This study demonstrates in a vertebrate embryo, how core-promoter variations define transcriptional-output in cells transitioning from a proliferative to cell-lineage specifying phenotype. Assessment of cell-proliferation across zebrafish embryo-development, using the FUCCI-transgenic cell-cycle- phase marker, revealed a spatial and lineage-specific separation in cell-cycling behaviour. To investigate the role differential promoter-usage plays in this process, cap-analysis-of-gene-expression (CAGE) was performed on cells segregated by cycling-dynamics.
Project description:Nucleosome organization and dynamics play a central role in controlling the DNA accessibility to regulatory factors of many critical cellular functions, especially gene regulation. However, despite extensive studies, the main factors determining nucleosome positioning and its fluctuation during cell cycle still remain elusive. Here, we present a large-scale study of nucleosome plasticity throughout the cell cycle and its interplay with gene expression based on genome-wide nucleosome positioning and mRNA abundance. We have clusterized distinct nucleosome architectures around transcription start sites and replication origins and studied their dynamics during the cell cycle progression. The most significant cell cycle-dependent changes occur at G1-S and G2-M transitions due to a large changes in gene expression in cell cycle regulatory genes. Taken together, our accurate study provides a dynamic picture of chromatin organization along cell cycle and its interplay with gene expression.
Project description:Cold storage (CS) is widely used to extend fruit postharvest. In peach, chilling injuries may cause intense juice loss leading to a dry ‘woolly’ texture of the fruit flesh. The disturbance, named woolliness, is associated to abnormal pectin metabolism and results in anatomical and physiological alterations. Application of gibberellic acid (GA) at the initial stages of pit hardening has been shown to impair woolliness incidence, however the mechanisms controlling the response remain unknown. We have employed genome wide transcription analyses to investigate the effects of GA application and CS of peaches. Approximately half (48.26%, 13846) of the investigated genes exhibited significant differential expression in response to the treatments. Gene ontology classes associated to cellular and developmental processes were overrepresented among the differentially regulated genes, whereas sequences classified in cell death and immune response categories were underrepresented. Gene set enrichment analyses demonstrated a predominant role of CS in repressing the transcription of genes associated to cell wall metabolism. In contrast, genes involved in hormone metabolism and signaling exhibited a more complex transcriptional response to the factors, indicating an extensive network of crosstalk between GA and low temperatures. Time course transcriptional profiling analyses also confirmed the involvement of cell wall metabolism genes in woolliness onset in peach. Overall, our results provide further insights on the mechanisms controlling the complex phenotypes associated to postharvest textural changes in peach. Four samples (CONT, CONTcs, GA3, GA3cs), each with three biological replicates (R1, R2 and R3), were analyzed. Control samples (CONT and CONTcs) consist of peach mesocarp not treated with GA3 at pit hardening, and either assayed at harvest (CONT) or after 15 days of cold storage (CONTcs). GA3 samples (GA3 and GA3cs) consist of peach mesocarp treated with GA3 at pit hardening, and either assayed at harvest (GA3) or after 15 days of cold storage (GA3cs).
Project description:The miR-16 family, which targets genes important for the G1-S transition, is a known modulator of the cell cycle, and members of this family are often deleted or down-regulated in many types of cancers. Here we report the reciprocal relationship - that of the cell cycle controlling the miR-16 family. Levels of this family increase rapidly as cells are arrested in G0. Conversely, as cells are released from G0 arrest, levels of the miR-16 family rapidly decrease. Such rapid changes are made possible by the unusual instabilities of several family members. The repression mediated by the miR-16 family is sensitive to these cell cycle changes, which suggests that the rapid up-regulation of the miR-16 family reinforces cell cycle arrest in G0. Upon cell cycle re-entry, the rapid decay of several members allows levels of the family to decrease, alleviating repression of target genes and allowing proper resumption of the cell cycle. Small RNAs were profiled by high-throughput sequencing either during synchronous release after serum starvation or during cell-cycle arrest by contact inhibition.
Project description:In this study, we develop computational tools for assignment of cell-cycle stages from single cell and bulk transcriptome data. We perform bulk RNA-Sequencing for mouse embryonic stem cells with known cell cycle stage.