0 5 NF-X2 nf-x2 NN 6 10 that that WDT 11 16 binds bind VBZ 17 19 to to TO 20 23 the the DT 24 27 DRA DRA NNP 28 34 X2-box X2-box NNP 35 37 is be VBZ 38 47 activator activator NN 48 55 protein protein NN 56 57 1 1 CD 57 58 . . . 59 69 Expression expression NN 70 77 cloning cloning NN 78 80 of of IN 81 86 c-Jun c-jun NN 86 87 . . . 89 94 Human human JJ 95 100 class class NN 101 103 II ii CD 104 107 MHC MHC NNP 108 110 Ag Ag NNP 111 114 are be VBP 115 116 a a DT 117 123 family family NN 124 126 of of IN 127 131 cell cell NN 132 139 surface surface NN 140 153 glycoproteins glycoprotein NNS 153 154 . . . 155 160 Their their PRP$ 161 173 constitutive constitutive JJ 174 184 expression expression NN 185 187 is be VBZ 188 195 limited limit VBN 196 198 to to TO 199 200 B B NNP 201 212 lymphocytes lymphocyte NNS 213 216 and and CC 217 223 thymic thymic JJ 224 234 epithelial epithelial JJ 235 240 cells cell NNS 240 241 . . . 242 244 In in IN 245 249 many many JJ 250 255 other other JJ 256 261 cells cell NNS 262 267 their their PRP$ 268 278 expression expression NN 279 282 can can MD 283 285 be be VB 286 293 induced induce VBN 294 296 by by IN 297 306 IFN-gamma IFN-gamma NNP 306 307 . . . 308 317 Conserved conserve VBN 318 326 upstream upstream JJ 327 335 promoter promoter NN 336 345 sequences sequence NNS 346 354 regulate regulate VBP 355 359 this this DT 360 375 tissue-specific tissue-specific JJ 376 386 expression expression NN 387 389 of of IN 390 395 class class NN 396 398 II ii CD 399 404 genes gene NNS 404 405 . . . 406 408 In in IN 409 412 the the DT 413 416 DRA DRA NNP 417 425 promoter promoter NN 425 426 , , , 427 430 one one CD 431 433 of of IN 434 439 these these DT 440 450 cis-acting cis-acting JJ 451 461 regulatory regulatory JJ 462 468 motifs motif NNS 469 471 is be VBZ 472 475 the the DT 476 482 X2-box x2-box NN 483 485 to to TO 486 491 which which WDT 492 499 nuclear nuclear JJ 500 506 factor factor NN 507 509 X2 x2 NN 510 511 ( ( ( 511 516 NF-X2 nf-x2 NN 516 517 ) ) ) 518 523 binds bind VBZ 523 524 . . . 525 529 Here here RB 529 530 , , , 531 533 we we PRP 534 541 present present VBP 542 545 the the DT 546 555 isolation isolation NN 556 559 and and CC 560 576 characterization characterization NN 577 579 of of IN 580 583 the the DT 584 595 full-length full-length JJ 596 600 cDNA cdna NN 601 606 clone clone NN 607 615 encoding encode VBG 616 621 NF-X2 nf-x2 NN 621 622 . . . 623 627 This this DT 628 632 cDNA cdna NN 633 638 clone clone NN 639 642 was be VBD 643 651 isolated isolate VBN 652 654 by by IN 655 665 expression expression NN 666 670 cDNA cdna NN 671 678 cloning cloning NN 678 679 , , , 680 683 and and CC 684 691 encodes encode VBZ 692 695 the the DT 696 701 human human JJ 702 707 c-Jun c-jun NN 708 715 protein protein NN 715 716 , , , 717 722 which which WDT 723 731 together together RB 732 736 with with IN 737 742 c-Fos c-fos NN 743 748 forms form VBZ 749 752 the the DT 753 766 heterodimeric heterodimeric JJ 767 776 activator activator NN 777 786 protein-1 protein-1 NN 787 800 transcription transcription NN 801 808 complex complex NN 808 809 . . . 810 817 Whereas whereas IN 818 829 c-Fos/c-Jun c-fos/c-jun NN 830 842 heterodimers heterodimer NNS 843 845 do do VBP 846 849 not not RB 850 855 exist exist VB 856 858 in in IN 859 860 B B NNP 861 866 cells cell NNS 866 867 , , , 868 872 they they PRP 873 877 form form VBP 878 881 and and CC 882 886 bind bind VBP 887 889 to to TO 890 893 the the DT 894 900 X2-box x2-box NN 901 903 in in IN 904 909 class class NN 910 912 II ii CD 913 926 nonexpressing nonexpressing JJ 927 932 cells cell NNS 932 933 . . . 934 938 Thus thus RB 938 939 , , , 940 951 c-Fos/c-Jun c-fos/c-jun NN 952 964 heterodimers heterodimer NNS 965 970 might might MD 971 981 contribute contribute VB 982 984 to to TO 985 988 the the DT 989 999 repression repression NN 1000 1002 of of IN 1003 1006 DRA DRA NNP 1007 1011 gene gene NN 1012 1022 expression expression NN 1022 1023 . . .