Project description:H2A.Z-nucleosomes participate in both euchromatin and heterochromatin and it has proven difficult to reveal how the disparate roles and stability features imparted by H2A.Z are connected. Using an in situ assay of nucleosome stability in nuclei of DT40 cells expressing engineered forms of the variant we show that H2A.Z is released from nucleosomes of peripheral heterochromatin at unusually high salt concentrations, compared to cells expressing C-terminally truncated H2A.Z. Binding of the tail-peptide (C9) to reconstituted nucleosomes, DNA and the nuclear lamina were detected. Upon treatment of HeLa nuclei with C9, the H2A.Z-nucleosomes assumed canonical stability, the peripheral heterochromatin became dispersed and overall nuclease sensitivity increased, recapitulating tail-dependent differences in DT40. When introduced into live cells, C9 elicited chromatin reorganization and transcriptional down-regulation of ~600 genes. Thus, large-scale epigenetic modulation can be achieved by targeting or making advantage of molecular interactions involving the C-terminal tail of H2A.Z.
Project description:The histone variant H2A.Z is evolutionarily conserved from yeast to vertebrates. H2A.Z regulates gene expression when localized to promoter region. Recently, we identified two genes encoding H2A.Z, H2A.Z-1 and H2A.Z-2 in vertebrate genome. However, it is not clear that both H2A.Z-1 and H2A.Z-2 were required for the function of H2A.Z in gene regulation. To address this issue, we generated the H2A.Z-1 and H2A.Z-2 double knock out (KO) cells in chicken DT40 cells. The expression pattern of H2A.Z-1 and H2A.Z-2 double KO cells was compared with WT cells to characterize the genes regulated by H2A.Z-1 and H2A.Z-2. We used microarrays to analysis the alternation of gene expression between WT and H2A.Z double KO cells and identify classes of up or down regulated gene by H2A.Z-1 and H2A.Z-2. In H2A.Z-1 and H2A.Z-2 double KO cells, H2A.Z-2 is knocked out constitutively, but H2A.Z-1 conditionally by tetracycline. The expression of H2A.Z-1 transgene is suppressed completely when H2A.Z-1 and H2A.Z-2 double KO cells culture with tetracycline for three days. For this reason, we prepared the total RNA of WT cells and H2A.Z-1and H2A.Z-2 double KO cells treated with tetracycline for three days and hybridization on Affymetrix microarrays.
Project description:The histone variant H2A.Z is evolutionarily conserved from yeast to vertebrates. H2A.Z regulates gene expression when localized to promoter region. Recently, we identified two genes encoding H2A.Z, H2A.Z-1 and H2A.Z-2 in vertebrate genome. However, it is not clear that both H2A.Z-1 and H2A.Z-2 were required for the function of H2A.Z in gene regulation. To address this issue, we generated the H2A.Z-1 and H2A.Z-2 double knock out (KO) cells in chicken DT40 cells. The expression pattern of H2A.Z-1 and H2A.Z-2 double KO cells was compared with WT cells to characterize the genes regulated by H2A.Z-1 and H2A.Z-2. We used microarrays to analysis the alternation of gene expression between WT and H2A.Z double KO cells and identify classes of up or down regulated gene by H2A.Z-1 and H2A.Z-2.
Project description:The histone variant H2A.Z is evolutionarily conserved from yeast to vertebrates. H2A.Z regulates gene expression when localized to promoter region. Recently, we identified two genes encoding H2A.Z, H2A.Z-1 and H2A.Z-2 in vertebrate genome. However, it is not clear that both H2A.Z-1 and H2A.Z-2 were required for the function of H2A.Z in gene regulation. To address this issue, we generated the H2A.Z-1 and H2A.Z-2 single knockout cells in chicken DT40 cells.We used microarrays to analysis the alternation of gene expression profiles in H2A.Z-1 KO and H2A.Z-2 KO cells and identify classes of up or down regulated gene by H2A.Z-1 and H2A.Z-2.
Project description:DT40 cells and a stable DT 40 cell line expressing OsTIR1 (clone 9) were treated with 500µM IAA for 6 hours. This experiment was conducued to see if auxin would induce a specific sets of genes in animal, like it does for plant cells. We didn't observe a significant difference between the mock control and IAA treatments in both DT40 cells and the stable cells.
Project description:The aim of experiment was to study on genome-wide level IRF4 target genes in chicken DT40 B cell line, by comparizon of gene expression profiles of IRF4-deficient DT40 cells with WT IRF4 DT40 cells .
Project description:The mechanisms that regulate H2A.Z and its requirement for transcription in differentiated mammalian cells remains ambiguous. In this study, we identified the interaction between the C-terminus of ANP32e and N-terminus of H2A.Z in a yeast two-hybrid screen. Knockdown of ANP32e resulted in proteasomal degradation and nuclear depletion of H2A.Z or of a chimeric green florescence protein fused to its N-terminus. This effect was reversed by inhibition of protein phosphatase 2A (PP2A) and, conversely, reproduced by overexpression of its catalytic subunit. Accordingly, knockdown of ANP32e inhibited phosphorylation of H2A.Z, whereas a mutation of serine-9 proved its requirement for both the protein’s stability and nuclear localization, as did knockdown of the nuclear mitogen and stress-induced kinase 1. Moreover, ANP32e’s knockdown also revealed its differential requirement for cell signaling and gene expression, whereas, genome-wide binding analysis confirmed its co-localization with H2A.Z at transcription start sites, as well as, gene bodies of inducible genes. The data also suggest that H2A.Z restricts transcription, which is moderated by ANP32e after induction of transcriptional activity of inducible and housekeeping genes vs. constitutively-expressed tissue-specific genes during cellular growth. Thus, ANP32e, through inhibition of PP2A, is required for nucleosomal inclusion of H2A.Z and the regulation of gene expression.
Project description:The histone variant H2A.Z is one of the most evolutionally conserved histone variants. In vertebrates, two isoforms, H2A.Z.1 and H2A.Z.2, are identified and are involved in multiple epigenetic regulations. However, the role of H2A.Z in epigenetic regulations largely remains unknown especially in vertebrate. Previously, we derived tetracycline-inducible H2A.Z isofmrs double knockout (DKO) cells by using DT40 cells. With this cell, we showed that H2A.Z DKO leads to defects in mitotic progression and gene expression. To elucidate the function of H2A.Z further, we established genetic complementation system and confirmed that introducing exogenous H2A.Z complemented phenotypes of H2A.Z DKO cells. Given that acetylation of the N-terminal tail of H2A.Z reportedly contributes to significant roles in H2A.Z functions, we introduced two types of H2A.Z mutants, non-acetylable H2A.Z (5KR-H2A.Z) and chimeric H2A.Z in which its N-terminal tail is replaced with that of canonical H2A (H2A-H2A.Z), into H2A.Z DKO cells. These H2A.Z mutants complemented defects in mitotic progression. However, significant transcriptional dysregulation was observed in H2A.Z DKO cells stably expressing 5KR-H2A.Z and H2A-H2A.Z. These results suggest that the core domain and the N-terminal tail of the vertebrate H2A.Z contribute individually to mitotic progression and transcription regulation, respectively.
Project description:SILAC quantitative proteomics was used to compare the whole cell proteomes of the differentially SILAC-labelled wild-type and acentrosomal (stil KO) DT40 cell lines.