Nuclear repositioning marks the selective exclusion of lineage-inappropriate transcription factor loci during T helper cell differentiation.
To address how heritable patterns of gene expression are acquired during the differentiation of Th1 and Th2 cells, we analyzed the nuclear position of lineage-restricted cytokine genes and their upstream regulators by 3-dimensional fluorescence in situ hybridization. During Th1 differentiation, GATA-3 and c-maf loci, which encode upstream regulators of Th2 cytokines, were progressively repositioned to centromeric heterochromatin as defined by a gamma-satellite repeat probe and/or the nuclear periphery, compartments that have been associated with transcriptional repression. A third transcription factor locus, T-bet, which controls Th1-specific programs, was subject to de novo CpG methylation in a Th2 cell clone. In contrast, we did not find repositioning of the cytokine gene loci IL-2, IL-3, IL-4 or IFN-gamma during T helper cell differentiation. Instead, IFN-gamma was constitutively associated with the nuclear periphery, even when primed for expression in Th1 cells. Our results suggest that Th1/Th2 lineage commitment and differentiation involve repositioning of the regulators of cytokine expression, rather than the cytokine genes themselves.
Hewitt
Susannah L
SL
Lymphocyte Development Group, MRC Clinical Sciences Centre, Imperial College London, London, UK.
High
Frances A
FA
Reiner
Steven L
SL
Fisher
Amanda G
AG
Merkenschlager
Matthias
M
D000818:Animals; D002454:Cell Differentiation / Q000235:genetics* / Q000502:physiology; D002467:Cell Nucleus / Q000235:genetics* / Q000378:metabolism; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000235:genetics*; D050990:GATA3 Transcription Factor; D006570:Heterochromatin / Q000378:metabolism; D007371:Interferon-gamma / Q000235:genetics / Q000378:metabolism; D051379:Mice; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D051257:Proto-Oncogene Proteins c-maf; D020825:T-Box Domain Proteins; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics; D000098815:T-bet Transcription Factor
D004268:DNA-Binding Proteins; D050990:GATA3 Transcription Factor; C494748:Gata3 protein, mouse; D006570:Heterochromatin; C495608:Maf protein, mouse; D011518:Proto-Oncogene Proteins; D051257:Proto-Oncogene Proteins c-maf; D020825:T-Box Domain Proteins; D000098815:T-bet Transcription Factor; D015534:Trans-Activators; D014157:Transcription Factors; D007371:Interferon-gamma