Analysis of the mouse embryonic stem cell regulatory networks obtained by ChIP-chip and ChIP-PET.
BACKGROUND
Genome-wide approaches have begun to reveal the transcriptional networks responsible for pluripotency in embryonic stem (ES) cells. Chromatin Immunoprecipitation (ChIP) followed either by hybridization to a microarray platform (ChIP-chip) or by DNA sequencing (ChIP-PET), has identified binding targets of the ES cell transcription factors OCT4 and NANOG in humans and mice, respectively. These studies have provided an outline of the transcriptional framework involved in maintaining pluripotency. Recent evidence with comparing multiple technologies suggests that expanding these datasets using different platforms would be a useful resource for examining the mechanisms underlying pluripotency regulation.


RESULTS
We have now identified OCT4 and NANOG genomic targets in mouse ES cells by ChIP-chip and provided the means to compare these data with previously reported ChIP-PET results in mouse ES cells. We have mapped the sequences of OCT4 and NANOG binding events from each dataset to genomic coordinates, providing a valuable resource to facilitate a better understanding of the ES cell regulatory circuitry. Interestingly, although considerable differences are observed in OCT4 and NANOG occupancy as identified by each method, a substantial number of targets in both datasets are enriched for genes that have known roles in cell-fate specification and that are differentially expressed upon Oct4 or Nanog knockdown.


CONCLUSIONS
This study suggests that each dataset is a partial representation of the overall ES cell regulatory circuitry, and through integrating binding data obtained by ChIP-chip and ChIP-PET, the methods presented here provide a useful means for integrating datasets obtained by different techniques in the future.
Mathur
Divya
D
Department of Biology, Massachusetts Institute of Technology, Ames Street, Cambridge, MA 02139, USA. dmathur@mit.edu.
Danford
Timothy W
TW
Boyer
Laurie A
LA
Young
Richard A
RA
Gifford
David K
DK
Jaenisch
Rudolf
R
D000818:Animals; D001665:Binding Sites; D047369:Chromatin Immunoprecipitation; D002874:Chromosome Mapping; D033481:Chromosomes, Mammalian; D053595:Embryonic Stem Cells / Q000378:metabolism*; D005786:Gene Expression Regulation; D053263:Gene Regulatory Networks; D023281:Genomics; D018398:Homeodomain Proteins / Q000378:metabolism*; D051379:Mice; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3 / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D034622:RNA Interference; D015398:Signal Transduction
D018398:Homeodomain Proteins; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse