0 3 The the DT 4 9 class class NN 10 12 II ii CD 13 28 trans-activator trans-activator NN 29 34 CIITA CIITA NNP 35 44 interacts interact VBZ 45 49 with with IN 50 53 the the DT 54 68 TBP-associated tbp-associated JJ 69 75 factor factor NN 76 83 TAFII32 tafii32 NN 83 84 . . . 86 89 The the DT 90 95 class class NN 96 98 II ii CD 99 105 trans- trans- JJ 106 115 activator activator NN 116 117 ( ( ( 117 122 CIITA CIITA NNP 122 123 ) ) ) 124 126 is be VBZ 127 130 the the DT 131 135 main main JJ 136 151 transcriptional transcriptional JJ 152 164 co-activator co-activator NN 165 168 for for IN 169 172 the the DT 173 183 expression expression NN 184 186 of of IN 187 190 MHC MHC NNP 191 196 class class NN 197 199 II ii CD 200 208 proteins protein NNS 208 209 . . . 210 213 Its its PRP$ 214 224 N-terminal n-terminal JJ 225 228 125 125 CD 229 234 amino amino NN 235 240 acids acid NNS 241 249 function function VBP 250 252 as as IN 253 255 an an DT 256 267 independent independent JJ 268 283 transcriptional transcriptional JJ 284 294 activation activation NN 295 301 domain domain NN 301 302 . . . 303 311 Analyses analysis NNS 312 314 of of IN 315 318 the the DT 319 326 primary primary JJ 327 332 amino amino NN 333 337 acid acid NN 338 346 sequence sequence NN 347 349 of of IN 350 353 the the DT 354 364 activation activation NN 365 371 domain domain NN 372 379 predict predict VBP 380 383 the the DT 384 392 presence presence NN 393 395 of of IN 396 401 three three CD 402 415 alpha-helices alpha-helice NNS 415 416 , , , 417 421 each each DT 422 426 with with IN 427 428 a a DT 429 433 high high JJ 434 444 proportion proportion NN 445 447 of of IN 448 454 acidic acidic JJ 455 463 residues residue NNS 463 464 . . . 465 470 Using use VBG 471 484 site-directed site-directed JJ 485 496 mutagenesis mutagenesis NN 496 497 , , , 498 500 we we PRP 501 506 found find VBD 507 511 that that IN 512 515 two two CD 516 518 of of IN 519 524 these these DT 525 534 predicted predict VBN 535 548 alpha-helices alpha-helice NNS 549 552 are be VBP 553 561 required require VBN 562 565 for for IN 566 570 full full JJ 571 586 transcriptional transcriptional JJ 587 597 activation activation NN 598 600 by by IN 601 606 CIITA CIITA NNP 606 607 . . . 608 616 Moreover moreover RB 616 617 , , , 618 619 a a DT 620 625 CIITA CIITA NNP 626 633 protein protein NN 634 636 in in IN 637 642 which which WDT 643 647 both both CC 648 658 functional functional JJ 659 672 alpha-helices alpha-helice NNS 673 677 have have VBP 678 682 been be VBN 683 690 deleted delete VBN 691 699 displays display VBZ 700 701 a a DT 702 710 dominant dominant JJ 711 719 negative negative JJ 720 729 phenotype phenotype NN 729 730 . . . 731 735 This this DT 736 746 activation activation NN 747 753 domain domain NN 754 756 of of IN 757 762 CIITA CIITA NNP 763 772 interacts interact VBZ 773 777 with with IN 778 781 the the DT 782 784 32 32 CD 785 788 kDa kda NN 789 796 subunit subunit NN 797 799 of of IN 800 803 the the DT 804 811 general general JJ 812 825 transcription transcription NN 826 833 complex complex NN 834 839 TFIID TFIID NNP 839 840 , , , 841 848 TAFII32 TAFII32 NNP 848 849 . . . 850 859 Decreased decrease VBN 860 875 transcriptional transcriptional JJ 876 886 activation activation NN 887 889 by by IN 890 900 N-terminal n-terminal JJ 901 910 deletions deletion NNS 911 913 of of IN 914 919 CIITA CIITA NNP 920 922 is be VBZ 923 933 correlated correlate VBN 934 942 directly directly RB 943 947 with with IN 948 953 their their PRP$ 954 961 reduced reduce VBN 962 969 binding binding NN 970 972 to to TO 973 980 TAFII32 TAFII32 NNP 980 981 . . . 982 984 We we PRP 985 993 conclude conclude VBP 994 998 that that IN 999 1011 interactions interaction NNS 1012 1019 between between IN 1020 1027 TAFII32 TAFII32 NNP 1028 1031 and and CC 1032 1037 CIITA CIITA NNP 1038 1041 are be VBP 1042 1053 responsible responsible JJ 1054 1057 for for IN 1058 1068 activation activation NN 1069 1071 of of IN 1072 1077 class class NN 1078 1080 II ii CD 1081 1086 genes gene NNS 1086 1087 . . .