Human immunodeficiency virus type 1 Tat increases cooperation between AP-1 and NFAT transcription factors in T cells.
Human immunodeficiency virus type 1 (HIV-1) Tat affects cellular gene expression through modulation of the activity of different transcription factors. Here, the role of Tat in the cooperation between nuclear factor of activated T cells (NFAT) and activator protein 1 (AP-1) transcription factors was investigated. Constitutive or transient Tat expression in Jurkat T cells enhanced cooperative NFAT/AP-1- but not AP-1-dependent transcription independent of its ability to transactivate the HIV-1 LTR. The enhancing effect of Tat took place after nuclear translocation of NFAT. Furthermore, transactivation of an NFAT/AP-1 reporter by transfection of NFAT and c-Jun was strongly enhanced by simultaneous Tat transfection. Moreover, intracellular Tat expression increased the binding of NFAT/AP-1 complexes to the interleukin 2 promoter without significantly altering NFAT- and AP-1-independent binding. HIV-1 Tat interacted with NFAT but not c-Jun. These results indicate that Tat interacts with NFAT, affecting its cooperation with AP-1, without altering independent binding of these transcription factors to DNA.
Hidalgo-Estévez
Alicia M
AM
Centro de Biología Molecular 'Severo Ochoa' (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
González
Esther
E
Centro de Biología Molecular 'Severo Ochoa' (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
Punzón
Carmen
C
Centro de Biología Molecular 'Severo Ochoa' (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
Fresno
Manuel
M
Centro de Biología Molecular 'Severo Ochoa' (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
D015696:Gene Products, tat / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D019169:Jurkat Cells; D008213:Lymphocyte Activation; D050778:NFATC Transcription Factors / Q000235:genetics / Q000378:metabolism*; D013601:T-Lymphocytes; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
D015696:Gene Products, tat; D050778:NFATC Transcription Factors; D018808:Transcription Factor AP-1; D048031:JNK Mitogen-Activated Protein Kinases