0 7 Precise precise JJ 8 17 alignment alignment NN 18 20 of of IN 21 26 sites site NNS 27 35 required require VBN 36 39 for for IN 40 42 mu mu NN 43 51 enhancer enhancer NN 52 62 activation activation NN 63 65 in in IN 66 67 B B NNP 68 73 cells cell NNS 73 74 . . . 76 79 The the DT 80 99 lymphocyte-specific lymphocyte-specific JJ 100 114 immunoglobulin immunoglobulin NN 115 117 mu mu NN 118 129 heavy-chain heavy-chain JJ 130 134 gene gene NN 135 143 intronic intronic JJ 144 152 enhancer enhancer NN 153 155 is be VBZ 156 165 regulated regulate VBN 166 168 by by IN 169 177 multiple multiple JJ 178 185 nuclear nuclear JJ 186 193 factors factor NNS 193 194 . . . 195 198 The the DT 199 209 previously previously RB 210 217 defined define VBN 218 225 minimal minimal JJ 226 234 enhancer enhancer NN 235 245 containing contain VBG 246 249 the the DT 250 253 muA mua NN 253 254 , , , 255 259 muE3 mue3 NN 259 260 , , , 261 264 and and CC 265 268 muB mub NN 269 274 sites site NNS 275 277 is be VBZ 278 292 transactivated transactivate VBN 293 295 by by IN 296 297 a a DT 298 309 combination combination NN 310 312 of of IN 313 316 the the DT 317 327 ETS-domain ETS-domain NNP 328 336 proteins protein NNS 337 341 PU.1 pu.1 NN 342 345 and and CC 346 351 Ets-1 ets-1 NN 352 354 in in IN 355 366 nonlymphoid nonlymphoid JJ 367 372 cells cell NNS 372 373 . . . 374 377 The the DT 378 382 core core NN 383 388 GGAAs ggaa NNS 389 391 of of IN 392 395 the the DT 396 399 muA mua NN 400 403 and and CC 404 407 muB mub NN 408 413 sites site NNS 414 417 are be VBP 418 427 separated separate VBN 428 430 by by IN 431 433 30 30 CD 434 445 nucleotides nucleotide NNS 445 446 , , , 447 457 suggesting suggest VBG 458 462 that that IN 463 466 ETS ets NN 467 475 proteins protein NNS 476 480 bind bind VBP 481 483 to to TO 484 489 these these DT 490 495 sites site NNS 496 500 from from IN 501 506 these these DT 507 511 same same JJ 512 516 side side NN 517 519 of of IN 520 523 the the DT 524 527 DNA dna NN 528 533 helix helix NN 533 534 . . . 535 537 We we PRP 538 544 tested test VBD 545 548 the the DT 549 558 necessity necessity NN 559 562 for for IN 563 574 appropriate appropriate JJ 575 582 spatial spatial JJ 583 592 alignment alignment NN 593 595 of of IN 596 601 these these DT 602 610 elements element NNS 611 613 by by IN 614 619 using use VBG 620 627 mutated mutate VBN 628 637 enhancers enhancer NNS 638 642 with with IN 643 650 altered alter VBN 651 659 spacings spacing NNS 659 660 . . . 661 662 A a DT 663 665 4- 4- CD 666 668 or or CC 669 674 10-bp 10-bp JJ 675 684 insertion insertion NN 685 692 between between IN 693 697 muE3 mue3 NN 698 701 and and CC 702 705 muB muB NNP 706 717 inactivated inactivate VBD 718 721 the the DT 722 724 mu mu NN 725 733 enhancer enhancer NN 734 736 in in IN 737 741 S194 s194 NN 742 748 plasma plasma NN 749 754 cells cell NNS 755 758 but but CC 759 762 did do VBD 763 766 not not RB 767 773 affect affect VB 774 776 in in FW 777 782 vitro vitro FW 783 790 binding binding NN 791 793 of of IN 794 799 Ets-1 Ets-1 NNP 799 800 , , , 801 805 PU.1 PU.1 NNP 805 806 , , , 807 809 or or CC 810 813 the the DT 814 826 muE3-binding mue3-binding JJ 827 834 protein protein NN 835 839 TFE3 tfe3 NN 839 840 , , , 841 846 alone alone RB 847 849 or or CC 850 852 in in IN 853 861 pairwise pairwise JJ 862 874 combinations combination NNS 874 875 . . . 876 884 Circular circular JJ 885 896 permutation permutation NN 897 900 and and CC 901 908 phasing phasing NN 909 917 analyses analysis NNS 918 930 demonstrated demonstrate VBD 931 935 that that IN 936 940 PU.1 pu.1 NN 941 948 binding binding NN 949 952 but but CC 953 956 not not RB 957 961 TFE3 tfe3 NN 962 964 or or CC 965 970 Ets-1 ets-1 NN 971 976 bends bend VBZ 977 979 mu mu NN 980 988 enhancer enhancer NN 989 992 DNA dna NN 993 999 toward toward IN 1000 1003 the the DT 1004 1009 major major JJ 1010 1016 groove groove NN 1016 1017 . . . 1018 1020 We we PRP 1021 1028 propose propose VBP 1029 1033 that that IN 1034 1037 the the DT 1038 1049 requirement requirement NN 1050 1053 for for IN 1054 1061 precise precise JJ 1062 1069 spacing spacing NN 1070 1072 of of IN 1073 1076 the the DT 1077 1080 muA mua NN 1081 1084 and and CC 1085 1088 muB mub NN 1089 1097 elements element NNS 1098 1100 is be VBZ 1101 1104 due due JJ 1105 1107 in in IN 1108 1112 part part NN 1113 1115 to to TO 1116 1117 a a DT 1118 1126 directed direct VBN 1127 1130 DNA dna NN 1131 1135 bend bend NN 1136 1143 induced induce VBN 1144 1146 by by IN 1147 1151 PU.1 PU.1 NNP 1151 1152 . . .