Functional and chromosomal clustering of genes responsive to 5-bromodeoxyuridine in human cells.

5-Bromodeoxyuridine immediately and dramatically induces senescence-associated genes in human cells. We examined changes in gene expression in HeLa cells using cDNA microarrays containing ca. 39,000 human genes or ESTs. Addition of 5-bromodeoxyuridine for 4 days changed expression of 2.6% of them twice more (1.5%) or less (1.1%) than control levels. We functionally categorized 191 genes that showed greater than four times increase or decrease, and found that they have a various function. These genes were assigned to various human chromosomes, and half of them seemed to cluster at a few regions on individual chromosomes. These results suggest that multiple genes collectively act to induce cellular senescence and chromatin structure has a role in expression of the genes.