0 5 BCL-6 BCL-6 NNP 5 6 , , , 7 8 a a DT 9 24 POZ/zinc-finger POZ/zinc-finger NNP 25 32 protein protein NN 32 33 , , , 34 36 is be VBZ 37 38 a a DT 39 56 sequence-specific sequence-specific JJ 57 72 transcriptional transcriptional JJ 73 82 repressor repressor NN 82 83 . . . 85 98 Approximately approximately RB 99 101 40 40 CD 101 102 % % NN 103 105 of of IN 106 113 diffuse diffuse JJ 114 119 large large JJ 120 124 cell cell NN 125 133 lymphoma lymphoma NN 134 137 are be VBP 138 148 associated associate VBN 149 153 with with IN 154 165 chromosomal chromosomal JJ 166 180 translocations translocation NNS 181 185 that that WDT 186 196 deregulate deregulate VBP 197 200 the the DT 201 211 expression expression NN 212 214 of of IN 215 218 the the DT 219 223 BCL6 BCL6 NNP 224 228 gene gene NN 229 231 by by IN 232 243 juxtaposing juxtapose VBG 244 256 heterologous heterologous JJ 257 266 promoters promoter NNS 267 269 to to TO 270 273 the the DT 274 279 BCL-6 bcl-6 NN 280 286 coding coding NN 287 293 domain domain NN 293 294 . . . 295 298 The the DT 299 303 BCL6 BCL6 NNP 304 308 gene gene NN 309 316 encodes encode VBZ 317 318 a a DT 319 325 95-kDa 95-kda JJ 326 333 protein protein NN 334 344 containing contain VBG 345 348 six six CD 349 359 C-terminal c-terminal JJ 360 371 zinc-finger zinc-finger NN 372 378 motifs motif NNS 379 382 and and CC 383 385 an an DT 386 396 N-terminal n-terminal JJ 397 400 POZ POZ NNP 401 407 domain domain NN 407 408 , , , 409 419 suggesting suggest VBG 420 424 that that IN 425 427 it it PRP 428 431 may may MD 432 440 function function VB 441 443 as as IN 444 445 a a DT 446 459 transcription transcription NN 460 466 factor factor NN 466 467 . . . 468 470 By by IN 471 476 using use VBG 477 478 a a DT 479 482 DNA dna NN 483 491 sequence sequence NN 492 500 selected select VBN 501 504 for for IN 505 508 its its PRP$ 509 516 ability ability NN 517 519 to to TO 520 524 bind bind VB 525 536 recombinant recombinant JJ 537 542 BCL-6 bcl-6 NN 543 545 in in FW 546 551 vitro vitro FW 551 552 , , , 553 555 we we PRP 556 560 show show VBP 561 565 here here RB 566 570 that that IN 571 576 BCL-6 bcl-6 NN 577 579 is be VBZ 580 587 present present JJ 588 590 in in IN 591 602 DNA-binding dna-binding JJ 603 612 complexes complex NNS 613 615 in in IN 616 623 nuclear nuclear JJ 624 632 extracts extract NNS 633 637 from from IN 638 645 various various JJ 646 652 B-cell b-cell NN 653 658 lines line NNS 658 659 . . . 660 662 In in IN 663 672 transient transient JJ 673 684 transfectin transfectin NN 685 696 experiments experiment NNS 696 697 , , , 698 702 BCL6 BCL6 NNP 703 706 can can MD 707 714 repress repress VB 715 728 transcription transcription NN 729 733 from from IN 734 743 promoters promoter NNS 744 750 linked link VBN 751 753 to to TO 754 757 its its PRP$ 758 761 DNA dna NN 762 768 target target NN 769 777 sequence sequence NN 778 781 and and CC 782 786 this this DT 787 795 activity activity NN 796 798 is be VBZ 799 808 dependent dependent JJ 809 813 upon upon IN 814 822 specific specific JJ 823 834 DNA-binding dna-binding NN 835 838 and and CC 839 842 the the DT 843 851 presence presence NN 852 854 of of IN 855 857 an an DT 858 864 intact intact JJ 865 875 N-terminal n-terminal JJ 876 880 half half NN 881 883 of of IN 884 887 the the DT 888 895 protein protein NN 895 896 . . . 897 899 We we PRP 900 911 demonstrate demonstrate VBP 912 916 that that IN 917 921 this this DT 922 926 part part NN 927 929 of of IN 930 933 the the DT 934 938 BCL6 BCL6 NNP 939 947 molecule molecule NN 948 956 contains contain VBZ 957 959 an an DT 960 970 autonomous autonomous JJ 971 985 transrepressor transrepressor NN 986 992 domain domain NN 993 996 and and CC 997 1001 that that IN 1002 1005 two two CD 1006 1019 noncontiguous noncontiguous JJ 1020 1027 regions region NNS 1027 1028 , , , 1029 1038 including include VBG 1039 1042 the the DT 1043 1046 POZ POZ NNP 1047 1052 motif motif NN 1052 1053 , , , 1054 1061 mediate mediate VBP 1062 1069 maximum maximum JJ 1070 1085 transrepressive transrepressive JJ 1086 1094 activity activity NN 1094 1095 . . . 1096 1101 These these DT 1102 1109 results result NNS 1110 1118 indicate indicate VBP 1119 1123 that that IN 1124 1127 the the DT 1128 1133 BCL-6 BCL-6 NNP 1134 1141 protein protein NN 1142 1145 can can MD 1146 1154 function function VB 1155 1157 as as IN 1158 1159 a a DT 1160 1177 sequence-specific sequence-specific JJ 1178 1193 transcriptional transcriptional JJ 1194 1203 repressor repressor NN 1204 1207 and and CC 1208 1212 have have VBP 1213 1225 implications implication NNS 1226 1229 for for IN 1230 1233 the the DT 1234 1238 role role NN 1239 1241 of of IN 1242 1246 BCL6 bcl6 NN 1247 1249 in in IN 1250 1256 normal normal JJ 1257 1265 lymphoid lymphoid JJ 1266 1277 development development NN 1278 1281 and and CC 1282 1297 lymphomagenesis lymphomagenesis NN 1297 1298 . . .