The duration of nuclear residence of NFAT determines the pattern of cytokine expression in human SCID T cells.
The expression of cytokine genes and other inducible genes is crucially dependent on the pattern and duration of signal transduction events that activate transcription factor binding to DNA. Two infant patients with SCID and a severe defect in T cell activation displayed an aberrant regulation of the transcription factor NFAT. Whereas the expression levels of the NFAT family members NFAT1, -2, and -4 were normal in the patients' T cells, dephosphorylation and nuclear translocation of these NFAT proteins occurred very transiently and incompletely upon stimulation. Only after inhibition of nuclear export with leptomycin B were we able to demonstrate a modest degree of nuclear translocation in the patients' T cells. This transient activation of NFAT was not sufficient to induce the expression of several cytokines, including IL-2, IL-3, IL-4, and IFN-gamma, whereas mRNA levels for macrophage inflammatory protein-1alpha, GM-CSF, and IL-13 were only moderately reduced. By limiting the time of NFAT activation in normal control cells using the calcineurin inhibitor cyclosporin A, we were able to mimic the cytokine expression pattern in SCID T cells, suggesting that the expression of different cytokine genes is differentially regulated by the duration of NFAT residence in the nucleus.
Feske
S
S
Center for Blood Research, Harvard Medical School, Boston, MA 02115, USA.
Draeger
R
R
Peter
H H
HH
Eichmann
K
K
Rao
A
A
D001692:Biological Transport / Q000235:genetics / Q000276:immunology; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D002675:Child, Preschool; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000378:metabolism / Q000502:physiology*; D005786:Gene Expression Regulation / Q000276:immunology; D006801:Humans; D007223:Infant; D008297:Male; D005810:Multigene Family; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins / Q000378:metabolism / Q000502:physiology*; D010766:Phosphorylation; D016511:Severe Combined Immunodeficiency / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D013997:Time Factors; D014157:Transcription Factors / Q000172:deficiency / Q000378:metabolism / Q000502:physiology*
D016207:Cytokines; D004268:DNA-Binding Proteins; D050778:NFATC Transcription Factors; C494006:NFATC2 protein, human; D009687:Nuclear Proteins; D014157:Transcription Factors