Project description:Progeroid syndromes are rare genetic disorders that phenotypically resemble natural aging. Despite identification of causal mutations, mechanisms that generate their clinical manifestations remain elusive. Here, we identified a DNA replication timing (RT) signature that distinguishes progeroid syndromes from normal aging and identifies TP63 gene as a new disease marker. Abnormal TP63 RT appears early during differentiation of progeroid iPSCs and is associated with altered gene variant expression. Our findings demonstrate the utility of RT signatures to identify novel biomarkers not detected by other methods, reveal abnormal TP63 RT as an early event in progeroid disease progression and offer TP63 gene regulation as a potential therapeutic target.
Project description:Progeroid syndromes are rare genetic disorders that phenotypically resemble natural aging. Despite identification of causal mutations, mechanisms that generate their clinical manifestations remain elusive. Here, we identified a DNA replication timing (RT) signature that distinguishes progeroid syndromes from normal aging and identifies TP63 gene as a new disease marker. Abnormal TP63 RT appears early during differentiation of progeroid iPSCs and is associated with altered gene variant expression. Our findings demonstrate the utility of RT signatures to identify novel biomarkers not detected by other methods, reveal abnormal TP63 RT as an early event in progeroid disease progression and offer TP63 gene regulation as a potential therapeutic target.
Project description:We have characterized allele-specific regulation of replication in human cultured primary basophilic erythroblasts using TimEX-seq. We show that in most of the genome the timing of replication of the two chromosome homologs is robustly and tightly regulated since the two alleles replicate almost at the same time. We also show that small genetic differences such as SNPs and indels do not affect replication timing. We identify two major causes of replication asynchrony: the presence of large structural variants and parental imprinting. Both are associated with the formation of asynchronously replicated domains that can reach several megabases in size. We also report that replication timing domains have a previously undetected fine structure.
Project description:We have characterized allele-specific regulation of replication in human cultured primary basophilic erythroblasts using TimEX-seq. We show that in most of the genome the timing of replication of the two chromosome homologs is robustly and tightly regulated since the two alleles replicate almost at the same time. We also show that small genetic differences such as SNPs and indels do not affect replication timing. We identify two major causes of replication asynchrony: the presence of large structural variants and parental imprinting. Both are associated with the formation of asynchronously replicated domains that can reach several megabases in size. We also report that replication timing domains have a previously undetected fine structure. Compare DNA content in cells in S and G1 phase of cell cycle using TimEX-seq The goal of these experiments was to measure the timing of replication in human basophilic erythroblasts in an allele-specific manner by comparing DNA content in cells in S and G1 phase of cell cycle using TimEX-seq. Cells in S phase were obtained by sorting propidium iodide stained exponentially growing basophilic erythroblasts produce after 14 days of culture of circulating peripheral blood stem and progenitor cells. The cells in G1, which are used to normalize the results from the cells in S phase for mapability, were circulating mononuclear cells (WBCs) which are in the G1 cell for the cell cycle at 99.5%. The processed files represent S/G1 ratio values which are surrogate values for the timing of replication. Allele-specific TimEX-seq profiles and hi-resolution non-allele specific profiles are provided at different smoothing levels. The following processed files are derived from the multiple files as indicated below; >FNY01_3_2_Ery_MAT_S.bed is generated from FNY01_3_2_Ery_round *_S_Phase.bed >FNY01_3_2_Ery_PAT_S.bed is generated from FNY01_3_2_Ery_round *_S_Phase.bed >FNY01_3_2_Ery_MAT_G1.bed is generated from FNY01_3_2_WBC_round *_G1_600.bed FNY01_3_2_WBC_round *_G1_300.bed >FNY01_3_2_WBC_PAT_G1.bed is generated from FNY01_3_2_WBC_round *_G1_600.bed FNY01_3_2_WBC_round *_G1_300.bed >FNY01_3_2_Ery_S_G1 ratio_MAT_100kb_smooth.bedGraph is from FNY01_3_2_Ery_MAT_S.bed FNY01_3_2_Ery_MAT_G1.bed >FNY01_3_2_Ery_S_G1 ratio_PAT_100kb_smooth.bedGraph is from FNY01_3_2_Ery_PAT_S.bed FNY01_3_2_Ery_PAT_G1.bed >FNY01_3_2_Ery_S_G1 ratio_unsmooth.bedGraph, FNY01_3_2_Ery_S_G1 ratio_20Kb_smooth.bedGraph, and FNY01_3_2_Ery_S_G1 ratio_100Kb_smooth.bedGraph are from FNY01_3_2_Ery_round *_S_Phase.bed FNY01_3_2_WBC_round *_G1_600.bed FNY01_3_2_WBC_round *_G1_300.bed >FNY01_3_2&3_3_Ery* files are generated from 14 .bed files linked to the corresponding sample records. Please note that *3_3* files follow the same pattern as *3_2*
Project description:The temporal order of DNA replication is modified during differentiation, but when a replication timing program is established and what alterations occur in vivo during embryogenesis are not known. Here we used zebrafish embryos to generate genome-wide, high-resolution replication timing maps throughout development. Unexpectedly, a non-random and defined replication timing program was evident in the rapid cell cycles before the midblastula transition. The majority of the genome undergoes dynamic shifts in replication timing throughout development as the timing program is decompressed, with many abrupt timing changes occurring during lineage specification. Strikingly, the long arm of chromosome 4 undergoes a developmentally regulated switch to late replication, reminiscent of mammalian X chromosome inactivation. This analysis also revealed a strong relationship between early replication and epigenetic marks at enhancers. Collectively, these data reveal the major changes in replication timing that occur during zebrafish embryogenesis, and demonstrate its dynamic regulation during vertebrate development.