Global survey of chromatin accessibility using DNA microarrays.
An increasing number of studies indicate a central role for chromatin remodeling in the regulation of gene expression. Current methods for high-resolution studies of the relationship between chromatin accessibility and transcription are low throughput, making a genome-wide study impractical. To enable the simultaneous measurement of the global chromatin accessibility state at the resolution of single genes, we developed the Chromatin Array technique, in which chromatin is separated by its condensation state using either the solubility differences of mono- and oligonucleosomes in specific buffers or controlled DNase I digestion and selection of the large refractory (condensed) DNA fragments. By probing with a comparative genomic hybridization style microarray, we can determine the condensation state of thousands of individual loci and correlate this with transcriptional activity. Applying this technique to the breast tumor model cell line, MCF7, we found that when the condensation is homogeneous in the population of cells, expression is inversely proportional to the level of accessibility and the two methods of accessibility-based target selection correlate well. Using functional annotation and comparative genomic hybridization data, we have begun to decipher the possible biological implications of the relationship between chromatin accessibility and expression.
Weil
M Ryan
MR
Program in Molecular Biophysics, Division of Cell and Molecular Biology, Southwestern Graduate School of Biomedical Science, UT Southwestern Medical Center, Dallas, Texas 75390, USA. rweil@mednet.swmed.edu
Widlak
Piotr
P
Minna
John D
JD
Garner
Harold R
HR
D001943:Breast Neoplasms / Q000737:chemistry / Q000235:genetics / Q000473:pathology; D002458:Cell Fractionation / Q000379:methods; D045744:Cell Line, Tumor; D002843:Chromatin / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D002874:Chromosome Mapping; D004273:DNA, Neoplasm / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism; D005784:Gene Amplification / Q000235:genetics; D017353:Gene Deletion; D020869:Gene Expression Profiling / Q000379:methods*; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D052138:Genes, Neoplasm / Q000235:genetics; D018740:Genetic Heterogeneity; D006801:Humans; D009690:Nucleic Acid Conformation; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods* / Q000592:standards; D012995:Solubility; D014158:Transcription, Genetic / Q000235:genetics
D002843:Chromatin; D004273:DNA, Neoplasm; D003850:Deoxyribonuclease I