Calcineurin-dependent nuclear translocation of a murine transcription factor NFATx: molecular cloning and functional characterization.
Members of the nuclear factor of activated T cells (NFAT) are involved in the induction of a number of cytokine genes. We report here cDNA cloning and chromosomal localization of a murine homologue of human NFATx, designated as mNFATx1, and its splicing variants mNFATx2 and m delta NFATx. Northern blot analysis showed mNFATx1 to be predominantly expressed in the thymus. mNFATx1, but not m delta NFATx, produced in COS-7 cells, bound to all NFAT-binding sites of the interleukin (IL)-2 and IL-4 promoters tested. Immunofluorescence assay showed that both mNFATx1 and m delta NFATx introduced into COS-7 cells localized predominantly to the cytoplasm, but did translocate to the nucleus, either by cotransfection with an active form of calcineurin or wild-type calcineurin followed by stimulation with calcium ionophore. Translocation of mNFATx1 correlated well with activation of the murine IL-2 promoter; mNFATx1 translocated under conditions described above, in combination with phorbol 12-myristate 13-acetate, activated the transiently transfected murine IL-2 promoter. Thus, nuclear-translocated mNFATx1 is involved in activation of the IL-2 promoter. These results provide the first evidence for the requirement of calcineurin in the control of mNFATx imported from the cytoplasm to the nucleus and implies that mNFATx may possibly be a substrate of calcineurin in vivo.
Liu
J
J
Department of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, Japan.
Koyano-Nakagawa
N
N
Amasaki
Y
Y
Saito-Ohara
F
F
Ikeuchi
T
T
Imai
S
S
Takano
T
T
Arai
N
N
Yokota
T
T
Arai
K
K
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D001692:Biological Transport; D015152:Blotting, Northern; D019556:COS Cells / Q000378:metabolism; D019703:Calcineurin; D002148:Calmodulin-Binding Proteins / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D002874:Chromosome Mapping; D002875:Chromosomes; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D006801:Humans; D007376:Interleukin-2 / Q000235:genetics / Q000378:metabolism; D015847:Interleukin-4 / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012326:RNA Splicing; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014018:Tissue Distribution; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection
D002148:Calmodulin-Binding Proteins; D004268:DNA-Binding Proteins; D007376:Interleukin-2; D050778:NFATC Transcription Factors; C494008:NFATC3 protein, human; C494009:Nfatc3 protein, mouse; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D015847:Interleukin-4; D019703:Calcineurin; D010749:Phosphoprotein Phosphatases