Martone Rebecca, Euskirchen Ghia, Bertone Paul, Hartman Stephen, Royce Thomas E, Luscombe Nicholas M, Rinn John L, Nelson F Kenneth, Miller Perry, Gerstein Mark, Weissman Sherman, Snyder Michael
Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520-8005, USA.
Proc Natl Acad Sci U S A. 2003 Oct 14;100(21):12247-52. doi: 10.1073/pnas.2135255100. Epub 2003 Oct 3.
We have mapped the chromosomal binding site distribution of a transcription factor in human cells. The NF-kappaB family of transcription factors plays an essential role in regulating the induction of genes involved in several physiological processes, including apoptosis, immunity, and inflammation. The binding sites of the NF-kappaB family member p65 were determined by using chromatin immunoprecipitation and a genomic microarray of human chromosome 22 DNA. Sites of binding were observed along the entire chromosome in both coding and noncoding regions, with an enrichment at the 5' end of genes. Strikingly, a significant proportion of binding was seen in intronic regions, demonstrating that transcription factor binding is not restricted to promoter regions. NF-kappaB binding was also found at genes whose expression was regulated by tumor necrosis factor alpha, a known inducer of NF-kappaB-dependent gene expression, as well as adjacent to genes whose expression is not affected by tumor necrosis factor alpha. Many of these latter genes are either known to be activated by NF-kappaB under other conditions or are consistent with NF-kappaB's role in the immune and apoptotic responses. Our results suggest that binding is not restricted to promoter regions and that NF-kappaB binding occurs at a significant number of genes whose expression is not altered, thereby suggesting that binding alone is not sufficient for gene activation.
我们已经绘制了一种转录因子在人类细胞中的染色体结合位点分布图。转录因子NF-κB家族在调节参与多种生理过程（包括细胞凋亡、免疫和炎症）的基因诱导方面发挥着重要作用。通过使用染色质免疫沉淀和人类22号染色体DNA的基因组微阵列，确定了NF-κB家族成员p65的结合位点。在整个染色体的编码区和非编码区均观察到结合位点，在基因的5'端富集。引人注目的是，在内含子区域发现了相当一部分结合位点，这表明转录因子结合并不局限于启动子区域。在其表达受肿瘤坏死因子α（一种已知的NF-κB依赖性基因表达诱导剂）调节的基因中，以及在其表达不受肿瘤坏死因子α影响的基因附近，也发现了NF-κB结合。许多后一类基因要么已知在其他条件下被NF-κB激活，要么与NF-κB在免疫和凋亡反应中的作用一致。我们的结果表明，结合并不局限于启动子区域，并且在大量表达未改变的基因中发生了NF-κB结合，从而表明仅结合不足以激活基因。
