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| Status |
Public on Aug 05, 2013 |
| Title |
A Hybrid Mechanism of Action for BCL6 in B Cells Defined by Formation of Functionally Distinct Complexes at Enhancers and Promoters |
| Organism |
Homo sapiens |
| Experiment type |
Expression profiling by high throughput sequencing
Genome binding/occupancy profiling by high throughput sequencing
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| Summary |
BCL6 is crucial for B-cell activation and lymphomagenesis. We used integrative genomics to explore BCL6 mechanism in normal and malignant B-cells. Surprisingly, BCL6 assembled distinct complexes at enhancers vs. promoters. At enhancers BCL6 preferentially recruited SMRT, which mediated H3K27 deacetylation through HDAC3, antagonized p300 activity and repressed transcription, but without decommissioning enhancers. This provides a biochemical
basis for toggling enhancers from the active to poised state. Virtually all SMRT was bound with BCL6 suggesting that in B-cells BCL6 uniquely sequesters SMRT from other factors. In promoters BCL6 preferentially recruited BCOR, but most potently repressed promoters where it
formed a distinctive ternary complex with SMRT and BCOR. Promoter repression was associated with decreased H3K36me3, H3K79me2 and Pol II elongation, linking BCL6 to transcriptional pausing.
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| Overall design |
We identified the binding patterns of BCL6, SMRT, NCOR and BCOR corepressors in normal germinal center B cells and a DLBCL cell line (OCI-Ly1) using ChIP-seq. Additionally we treated lymphoma cells with siRNA against BCL6 and a non-targeted siRNA (NT control) and performed RNA-seq to identify the genes bound and repressed by BCL6. RNA-seq experiments were performed at 24h and 48h after siRNA treatments. Additional biological triplicate RNA-seq experiments were performed at 48h after BCL6 knockdown. Furthermore, a series of histone mark ChIP-seq and RNA polymerase ChIP-seq (total, Ser5-P and Ser2-P) were preformed to capture the chromatin states associated with the formation of BCL6 corepressor complexes.
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| Contributor(s) |
Hatzi K, Elemento O, Melnick A |
| Citation(s) |
23911289, 26521025 |
| Submission date |
May 13, 2011 |
| Last update date |
Mar 30, 2020 |
| Contact name |
Katerina Hatzi |
| E-mail(s) |
kac2029@med.cornell.edu
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| Organization name |
WCMC
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| Department |
Hematology/Oncology
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| Lab |
Ari Melnick
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| Street address |
413 E 69th Street, BB-1462
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| City |
New York |
| State/province |
NY |
| ZIP/Postal code |
10021 |
| Country |
USA |
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| Platforms (3) |
| GPL10999 |
Illumina Genome Analyzer IIx (Homo sapiens) |
| GPL11154 |
Illumina HiSeq 2000 (Homo sapiens) |
| GPL15433 |
Illumina HiSeq 1000 (Homo sapiens) |
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| Samples (46)
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| Relations |
| BioProject |
PRJNA138597 |
| SRA |
SRP007525 |
| Supplementary file |
Size |
Download |
File type/resource |
| GSE29282_ChIP-seq_antibodies.txt.gz |
400 b |
(ftp)(http) |
TXT |
| GSE29282_RAW.tar |
13.2 Gb |
(http)(custom) |
TAR (of BED, BW, WIG) |
SRA Run Selector |
| Processed data provided as supplementary file |
| Raw data are available in SRA |
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