Variegated gene expression caused by cell-specific long-range DNA interactions.

Hubrecht Institute-KNAW and University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands.
Nature Cell Biology (Impact Factor: 20.06). 06/2011; 13(8):944-51. DOI: 10.1038/ncb2278
Source: PubMed

ABSTRACT Mammalian genomes contain numerous regulatory DNA sites with unknown target genes. We used mice with an extra β-globin locus control region (LCR) to investigate how a regulator searches the genome for target genes. We find that the LCR samples a restricted nuclear subvolume, wherein it preferentially contacts genes controlled by shared transcription factors. No contacted gene is detectably upregulated except for endogenous β-globin genes located on another chromosome. This demonstrates genetically that mammalian trans activation is possible, but suggests that it will be rare. Trans activation occurs not pan-cellularly, but in 'jackpot' cells enriched for the interchromosomal interaction. Therefore, cell-specific long-range DNA contacts can cause variegated expression.

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