0 3 The the DT 4 14 ubiquitous ubiquitous JJ 15 30 octamer-binding octamer-binding JJ 31 41 protein(s) protein(s) NN 42 44 is be VBZ 45 55 sufficient sufficient JJ 56 59 for for IN 60 73 transcription transcription NN 74 76 of of IN 77 91 immunoglobulin immunoglobulin NN 92 97 genes gene NNS 97 98 . . . 100 103 All all DT 104 118 immunoglobulin immunoglobulin NN 119 124 genes gene NNS 125 132 contain contain VBP 133 134 a a DT 135 144 conserved conserve VBN 145 159 octanucleotide octanucleotide NN 160 168 promoter promoter NN 169 176 element element NN 176 177 , , , 178 186 ATGCAAAT ATGCAAAT NNP 186 187 , , , 188 193 which which WDT 194 197 has have VBZ 198 202 been be VBN 203 208 shown show VBN 209 211 to to TO 212 214 be be VB 215 223 required require VBN 224 227 for for IN 228 233 their their PRP$ 234 240 normal normal JJ 241 256 B-cell-specific b-cell-specific JJ 257 270 transcription transcription NN 270 271 . . . 272 280 Proteins Protein NNPS 281 285 that that WDT 286 290 bind bind VBP 291 295 this this DT 296 303 octamer octamer NN 304 308 have have VBP 309 313 been be VBN 314 322 purified purify VBN 322 323 , , , 324 327 and and CC 328 333 cDNAs cdna NNS 334 342 encoding encode VBG 343 358 octamer-binding octamer-binding JJ 359 367 proteins protein NNS 368 372 have have VBP 373 377 been be VBN 378 384 cloned clone VBN 384 385 . . . 386 390 Some some DT 391 393 of of IN 394 399 these these DT 400 408 proteins protein NNS 409 410 ( ( ( 410 418 referred refer VBN 419 421 to to TO 422 424 as as IN 425 430 OTF-2 otf-2 NN 430 431 ) ) ) 432 435 are be VBP 436 444 lymphoid lymphoid JJ 445 453 specific specific JJ 453 454 , , , 455 462 whereas whereas IN 463 465 at at IN 466 471 least least JJS 472 475 one one CD 476 481 other other JJ 481 482 , , , 483 486 and and CC 487 495 possibly possibly RB 496 500 more more JJR 501 502 ( ( ( 502 510 referred refer VBN 511 513 to to TO 514 516 as as IN 517 522 OTF-1 otf-1 NN 522 523 ) ) ) 523 524 , , , 525 527 is be VBZ 528 533 found find VBN 534 546 ubiquitously ubiquitously RB 547 549 in in IN 550 553 all all DT 554 558 cell cell NN 559 564 types type NNS 564 565 . . . 566 569 The the DT 570 575 exact exact JJ 576 580 role role NN 581 583 of of IN 584 589 these these DT 590 599 different different JJ 600 608 proteins protein NNS 609 611 in in IN 612 621 directing direct VBG 622 625 the the DT 626 641 tissue-specific tissue-specific JJ 642 652 expression expression NN 653 655 of of IN 656 670 immunoglobulin immunoglobulin NN 671 676 genes gene NNS 677 679 is be VBZ 680 687 unclear unclear JJ 687 688 . . . 689 691 We we PRP 692 696 have have VBP 697 707 identified identify VBN 708 711 two two CD 712 717 human human JJ 718 728 pre-B-cell pre-b-cell NN 729 734 lines line NNS 735 739 that that WDT 740 747 contain contain VBP 748 757 extremely extremely RB 758 761 low low JJ 762 768 levels level NNS 769 771 of of IN 772 777 OTF-2 otf-2 NN 778 781 yet yet CC 782 787 still still RB 788 795 express express VBP 796 800 high high JJ 801 807 levels level NNS 808 810 of of IN 811 823 steady-state steady-state JJ 824 838 immunoglobulin immunoglobulin NN 839 850 heavy-chain heavy-chain JJ 851 855 mRNA mrna NN 856 858 in in FW 859 863 vivo vivo FW 864 867 and and CC 868 879 efficiently efficiently RB 880 890 transcribe transcribe VBP 891 893 an an DT 894 908 immunoglobulin immunoglobulin NN 909 913 gene gene NN 914 916 in in FW 917 922 vitro vitro FW 922 923 . . . 924 932 Addition addition NN 933 935 of of IN 936 937 a a DT 938 944 highly highly RB 945 953 enriched enrich VBN 954 965 preparation preparation NN 966 968 of of IN 969 974 OTF-1 otf-1 NN 975 979 made make VBN 980 984 from from IN 985 988 one one CD 989 991 of of IN 992 997 these these DT 998 1003 pre-B pre-b JJ 1004 1009 cells cell NNS 1010 1012 or or CC 1013 1017 from from IN 1018 1022 HeLa HeLa NNP 1023 1028 cells cell NNS 1029 1041 specifically specifically RB 1042 1052 stimulated stimulate VBN 1053 1055 in in FW 1056 1061 vitro vitro FW 1062 1075 transcription transcription NN 1076 1078 of of IN 1079 1081 an an DT 1082 1096 immunoglobulin immunoglobulin NN 1097 1101 gene gene NN 1101 1102 . . . 1103 1114 Furthermore furthermore RB 1114 1115 , , , 1116 1121 OFT-1 OFT-1 NNP 1122 1130 appeared appear VBD 1131 1133 to to TO 1134 1138 have have VB 1139 1152 approximately approximately RB 1153 1156 the the DT 1157 1161 same same JJ 1162 1177 transactivation transactivation NN 1178 1185 ability ability NN 1186 1188 as as IN 1189 1194 OTF-2 otf-2 NN 1195 1199 when when WRB 1200 1210 normalized normalize VBN 1211 1214 for for IN 1215 1222 binding binding NN 1223 1231 activity activity NN 1231 1232 . . . 1233 1238 These these DT 1239 1246 results result NNS 1247 1254 suggest suggest VBP 1255 1259 that that IN 1260 1265 OTF-1 otf-1 NN 1265 1266 , , , 1267 1274 without without IN 1275 1280 OTF-2 otf-2 NN 1280 1281 , , , 1282 1284 is be VBZ 1285 1295 sufficient sufficient JJ 1296 1299 for for IN 1300 1313 transcription transcription NN 1314 1316 of of IN 1317 1331 immunoglobulin immunoglobulin NN 1332 1337 genes gene NNS 1338 1341 and and CC 1342 1346 that that IN 1347 1352 OTF-2 otf-2 NN 1353 1358 alone alone RB 1359 1361 is be VBZ 1362 1365 not not RB 1366 1377 responsible responsible JJ 1378 1381 for for IN 1382 1385 the the DT 1386 1401 B-cell-specific b-cell-specific JJ 1402 1412 regulation regulation NN 1413 1415 of of IN 1416 1430 immunoglobulin immunoglobulin NN 1431 1435 gene gene NN 1436 1446 expression expression NN 1446 1447 . . .