Transcriptional regulation of cytokine genes in nontransformed T cells. Apparent constitutive signals in run-on assays can be caused by repeat sequences.
Cytokines are immunoregulatory proteins that are secreted by T lymphocytes and other cells upon activation. A controversy exists as to whether the induction of cytokine production is mediated at the transcriptional level by the initiation of RNA synthesis or at the post-transcriptional level by the enhancement of mRNA stability. We show that in a nontransformed T cell clone the induction of all of the cytokines that are analyzed in this report is mediated transcriptionally. We also found that a constitutive signal was seen in resting cells when the probes used in the nuclear run-on assay contained some potential cross-hybridizing sequences, for example a poly (A) tract in a cDNA probe. This observation could explain the constitutive signals seen in other studies that claim cytokine production is regulated by differential mRNA stability.
Brorson
K A
KA
Laboratory of Cellular and Molecular Immunology, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD 20892.
Beverly
B
B
Kang
S M
SM
Lenardo
M
M
Schwartz
R H
RH
D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D002467:Cell Nucleus / Q000378:metabolism; D002999:Clone Cells; D016207:Cytokines / Q000235:genetics*; D015342:DNA Probes; D005786:Gene Expression Regulation; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000235:genetics; D007376:Interleukin-2 / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D013601:T-Lymphocytes / Q000502:physiology*; D014158:Transcription, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
D016207:Cytokines; D015342:DNA Probes; D007376:Interleukin-2; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D016178:Granulocyte-Macrophage Colony-Stimulating Factor