Project description:We expressed either a wt or a phosphomutant version of ZFP36L1 in IMR90 ER:RAS cells. 7 days upon RAS induction (when the cells reach a fully senescent phenotype) we collected the RNA. ZFP36L1 is a RNA binding protein that binds to AU-rich elements in the 3âUTR of mRNAs and triggers their degradation. Our previous experiments showed that the activity of ZFP36L1 was key in the regulation of the senescent phenotype.By performing RNAseq we have uncovered the effect of expressing a constitutively active mutant of ZFP36L1 within the senescent transcriptome. 4 samples examined: Non-senescent cells (EV - 4OHT), Senescent cells (EV + 4OHT), Senescent cells expressing ZFP36L1wt and Senescent cells expressing ZFP36L1mut
Project description:We observe preferential accumulation of gH2AX at chromosome ends upon irradiation comparison of quiescent vs senescent human fibroblasts
Project description:The expansion of repressive epigenetic marks has been implicated in heterochromatin formation during embryonic development, but the general applicability of this mechanism is unclear. Here we show that nuclear rearrangement of repressive histone marks H3K9me3 and H3K27me3 into non-overlapping structural layers characterizes senescence-associated heterochromatic foci (SAHF) formation in human fibroblasts. However, the global landscape of these repressive marks remains unchanged upon SAHF formation, suggesting that in somatic cells heterochromatin can be formed through the spatial repositioning of pre-existing repressively marked histones. This model is reinforced by the correlation of pre-senescent replication timing with both the subsequent layered structure of SAHFs and the global landscape of the repressive marks, allowing us to integrate microscopic and genomic information. Furthermore, modulation of SAHF structure does not affect the occupancy of these repressive marks nor vice versa. These experiments reveal that high-order heterochromatin formation and epigenetic remodeling of the genome can be discrete events. ChIP-seq for different histone marks in both growing and Ras-induced senescent fibroblasts, in the presence or absence of certain sh-RNAs K9me3Grow2.bed (growing) Chip Seq Analysis of H3K9me3 in ER:Ras expressing IMR90 human diploid fibroblasts d6 4OHT K9me3Sen2.bed (senescent) Chip Seq Analysis of H3K9me3 in ER:Ras expressing IMR90 human diploid fibroblasts with no treatment K9me2Grow3.bed (growing) Chip Seq Analysis of H3K9me2 in ER:Ras expressing IMR90 human diploid fibroblasts with no treatment K9me2Sen3.bed (senescent) Chip Seq Analysis of H3K9me2 in ER:Ras expressing IMR90 human diploid fibroblasts d6 4OHT K27me3Sen3.bed (senescent) Chip Seq Analysis of H3K27me3 in ER:Ras expressing IMR90 human diploid fibroblasts d6 4OHT K27me3Grow2.bed (growing) Chip Seq Analysis of H3K27me3 in ER:Ras expressing IMR90 human diploid fibroblasts with no treatment K36me3Grow2.bed (growing) Chip Seq Analysis of H3K36me3 in ER:Ras expressing IMR90 human diploid fibroblasts with no treatment K36me3Sen2.bed (senescent) Chip Seq Analysis of H3K36me3 in ER:Ras expressing IMR90 human diploid fibroblasts d6 4OHT K4me3Grow2.bed (growing) Chip Seq Analysis of H3K4me3 in ER:Ras expressing IMR90 human diploid fibroblasts with no treatment K4me3Sen3.bed (senescent) Chip Seq Analysis of H3K4me3 in ER:Ras expressing IMR90 human diploid fibroblasts d6 4OHT
Project description:We expressed either a wt or a phosphomutant version of ZFP36L1 in IMR90 ER:RAS cells. 7 days upon RAS induction (when the cells reach a fully senescent phenotype) we collected the RNA. ZFP36L1 is a RNA binding protein that binds to AU-rich elements in the 3’UTR of mRNAs and triggers their degradation. Our previous experiments showed that the activity of ZFP36L1 was key in the regulation of the senescent phenotype.By performing RNAseq we have uncovered the effect of expressing a constitutively active mutant of ZFP36L1 within the senescent transcriptome.