0 7 Cloning Cloning NNP 8 11 and and CC 12 22 functional functional JJ 23 39 characterization characterization NN 40 42 of of IN 43 48 early early JJ 49 55 B-cell b-cell NN 56 62 factor factor NN 62 63 , , , 64 65 a a DT 66 75 regulator regulator NN 76 78 of of IN 79 98 lymphocyte-specific lymphocyte-specific JJ 99 103 gene gene NN 104 114 expression expression NN 114 115 . . . 117 122 Early early JJ 123 129 B-cell b-cell NN 130 136 factor factor NN 137 138 ( ( ( 138 141 EBF EBF NNP 141 142 ) ) ) 143 146 was be VBD 147 157 identified identify VBN 158 168 previously previously RB 169 171 as as IN 172 173 a a DT 174 189 tissue-specific tissue-specific JJ 190 193 and and CC 194 209 differentiation differentiation NN 210 224 stage-specific stage-specific JJ 225 236 DNA-binding dna-binding JJ 237 244 protein protein NN 245 249 that that WDT 250 262 participates participate VBZ 263 265 in in IN 266 269 the the DT 270 280 regulation regulation NN 281 283 of of IN 284 287 the the DT 288 293 pre-B pre-b NN 294 297 and and CC 298 299 B B NNP 300 319 lymphocyte-specific lymphocyte-specific JJ 320 324 mb-1 mb-1 NN 325 329 gene gene NN 329 330 . . . 331 338 Partial partial JJ 339 344 amino amino JJ 345 349 acid acid NN 350 359 sequences sequence NNS 360 368 obtained obtain VBN 369 373 from from IN 374 382 purified purify VBN 383 386 EBF ebf NN 387 391 were be VBD 392 396 used use VBN 397 399 to to TO 400 407 isolate isolate VB 408 412 cDNA cdna NN 413 419 clones clone NNS 419 420 , , , 421 426 which which WDT 427 429 by by IN 430 438 multiple multiple JJ 439 447 criteria criterion NNS 448 454 encode encode VBP 455 458 EBF EBF NNP 458 459 . . . 460 463 The the DT 464 475 recombinant recombinant JJ 476 487 polypeptide polypeptide NN 488 494 formed form VBD 495 512 sequence-specific sequence-specific JJ 513 522 complexes complex NNS 523 527 with with IN 528 531 the the DT 532 543 EBF-binding ebf-binding JJ 544 548 site site NN 549 551 in in IN 552 555 the the DT 556 560 mb-1 mb-1 NN 561 569 promoter promoter NN 569 570 . . . 571 574 The the DT 575 579 cDNA cdna NN 580 590 hybridized hybridize VBD 591 593 to to TO 594 602 multiple multiple JJ 603 614 transcripts transcript NNS 615 617 in in IN 618 623 pre-B pre-b NN 624 627 and and CC 628 634 B-cell b-cell NN 635 640 lines line NNS 640 641 , , , 642 645 but but CC 646 657 transcripts transcript NNS 658 662 were be VBD 663 666 not not RB 667 675 detected detect VBN 676 678 at at IN 679 690 significant significant JJ 691 697 levels level NNS 698 700 in in IN 701 713 plasmacytoma plasmacytoma NN 713 714 , , , 715 721 T-cell T-cell NNP 721 722 , , , 723 726 and and CC 727 738 nonlymphoid nonlymphoid JJ 739 743 cell cell NN 744 749 lines line NNS 749 750 . . . 751 761 Expression expression NN 762 764 of of IN 765 776 recombinant recombinant JJ 777 780 EBF ebf NN 781 783 in in IN 784 795 transfected transfecte VBN 796 807 nonlymphoid nonlymphoid JJ 808 813 cells cell NNS 814 822 strongly strongly RB 823 832 activated activate VBD 833 846 transcription transcription NN 847 851 from from IN 852 860 reporter reporter NN 861 869 plasmids plasmid NNS 870 880 containing contain VBG 881 891 functional functional JJ 892 903 EBF-binding ebf-binding JJ 904 909 sites site NNS 909 910 . . . 911 919 Analysis Analysis NNP 920 922 of of IN 923 926 DNA DNA NNP 927 934 binding binding NN 935 937 by by IN 938 946 deletion deletion NN 947 954 mutants mutant NNS 955 957 of of IN 958 961 EBF EBF NNP 962 972 identified identify VBD 973 975 an an DT 976 990 amino-terminal amino-terminal JJ 991 1004 cysteine-rich cysteine-rich JJ 1005 1016 DNA-binding dna-binding JJ 1017 1023 domain domain NN 1024 1031 lacking lack VBG 1032 1039 obvious obvious JJ 1040 1048 sequence sequence NN 1049 1059 similarity similarity NN 1060 1062 to to TO 1063 1068 known know VBN 1069 1082 transcription transcription NN 1083 1090 factors factor NNS 1090 1091 . . . 1092 1103 DNA-binding dna-binding JJ 1104 1110 assays assay NNS 1111 1115 with with IN 1116 1128 cotranslated cotranslate VBN 1129 1138 wild-type wild-type JJ 1139 1142 and and CC 1143 1152 truncated truncated JJ 1153 1158 forms form NNS 1159 1161 of of IN 1162 1165 EBF EBF NNP 1166 1175 indicated indicate VBD 1176 1180 that that IN 1181 1184 the the DT 1185 1192 protein protein NN 1193 1202 interacts interact VBZ 1203 1207 with with IN 1208 1211 its its PRP$ 1212 1216 site site NN 1217 1219 as as IN 1220 1221 a a DT 1222 1231 homodimer homodimer NN 1231 1232 . . . 1233 1242 Deletions deletion NNS 1243 1253 delineated delineate VBD 1254 1255 a a DT 1256 1272 carboxy-terminal carboxy-terminal JJ 1273 1285 dimerization dimerization NN 1286 1292 region region NN 1293 1303 containing contain VBG 1304 1307 two two CD 1308 1315 repeats repeat NNS 1316 1318 of of IN 1319 1321 15 15 CD 1322 1327 amino amino NN 1328 1333 acids acid NNS 1334 1338 that that WDT 1339 1343 show show VBP 1344 1354 similarity similarity NN 1355 1359 with with IN 1360 1363 the the DT 1364 1376 dimerization dimerization NN 1377 1384 domains domain NNS 1385 1387 of of IN 1388 1410 basic-helix-loop-helix basic-helix-loop-helix JJ 1411 1419 proteins protein NNS 1419 1420 . . . 1421 1429 Together together RB 1429 1430 , , , 1431 1436 these these DT 1437 1441 data datum NNS 1442 1449 suggest suggest VBP 1450 1454 that that IN 1455 1458 EBF EBF NNP 1459 1469 represents represent VBZ 1470 1471 a a DT 1472 1477 novel novel JJ 1478 1487 regulator regulator NN 1488 1490 of of IN 1491 1492 B B NNP 1493 1512 lymphocyte-specific lymphocyte-specific JJ 1513 1517 gene gene NN 1518 1528 expression expression NN 1528 1529 . . .