0 8 Distinct distinct JJ 9 16 DNase-I DNase-I NNP 17 31 hypersensitive hypersensitive JJ 32 37 sites site NNS 38 41 are be VBP 42 52 associated associate VBN 53 57 with with IN 58 63 TAL-1 tal-1 NN 64 77 transcription transcription NN 78 80 in in IN 81 90 erythroid erythroid JJ 91 94 and and CC 95 101 T-cell t-cell NN 102 107 lines line NNS 107 108 . . . 110 113 The the DT 114 119 tal-1 tal-1 NN 120 124 gene gene NN 124 125 , , , 126 136 frequently frequently RB 137 146 activated activate VBN 147 149 in in IN 150 155 human human JJ 156 162 T-cell t-cell NN 163 168 acute acute JJ 169 182 lymphoblastic lymphoblastic JJ 183 191 leukemia leukemia NN 192 193 ( ( ( 193 198 T-ALL T-ALL NNP 198 199 ) ) ) 199 200 , , , 201 203 is be VBZ 204 213 expressed express VBN 214 216 in in IN 217 220 the the DT 221 230 erythroid erythroid JJ 230 231 , , , 232 246 megakaryocytic megakaryocytic JJ 246 247 , , , 248 251 and and CC 252 256 mast mast NN 257 261 cell cell NN 262 270 lineages lineage NNS 271 277 during during IN 278 284 normal normal JJ 285 298 hematopoiesis hematopoiesis NN 298 299 . . . 300 302 To to TO 303 307 gain gain VB 308 315 further further JJ 316 323 insight insight NN 324 328 into into IN 329 332 the the DT 333 342 molecular molecular JJ 343 353 mechanisms mechanism NNS 354 358 that that WDT 359 366 control control VBP 367 372 tal-1 tal-1 NN 373 383 expression expression NN 383 384 , , , 385 387 we we PRP 388 400 investigated investigate VBD 401 406 tal-1 tal-1 NN 407 416 chromatin chromatin NN 417 426 structure structure NN 427 429 in in IN 430 454 erythroid/megakaryocytic erythroid/megakaryocytic JJ 455 459 cell cell NN 460 465 lines line NNS 466 469 and and CC 470 472 in in IN 473 479 T-cell t-cell NN 480 485 lines line NNS 486 492 either either CC 493 497 with with IN 498 500 or or CC 501 508 without without IN 509 514 tal-1 tal-1 NN 515 529 rearrangements rearrangement NNS 529 530 . . . 531 536 Tal-1 tal-1 NN 537 550 transcription transcription NN 551 554 was be VBD 555 560 shown show VBN 561 563 to to TO 564 566 be be VB 567 578 monoallelic monoallelic JJ 579 581 in in IN 582 588 Jurkat Jurkat NNP 588 589 , , , 590 591 a a DT 592 598 T-cell t-cell NN 599 603 line line NN 604 608 that that WDT 609 618 expresses express VBZ 619 624 tal-1 tal-1 NN 625 627 in in IN 628 631 the the DT 632 639 absence absence NN 640 642 of of IN 643 651 apparent apparent JJ 652 659 genomic genomic JJ 660 670 alteration alteration NN 671 673 of of IN 674 677 the the DT 678 683 locus locus NN 683 684 . . . 685 696 Methylation methylation NN 697 704 studies study NNS 705 714 indicated indicate VBD 715 719 that that IN 720 723 the the DT 724 730 tal-15 tal-15 NN 730 731 ’ ' POS 732 739 GC-rich gc-rich JJ 740 746 region region NN 747 754 behaves behave VBZ 755 759 like like IN 760 761 a a DT 762 765 CpG CpG NNP 766 772 island island NN 772 773 , , , 774 788 hypomethylated hypomethylate VBN 789 791 in in IN 792 798 normal normal JJ 799 804 cells cell NNS 804 805 , , , 806 809 and and CC 810 820 methylated methylate VBN 821 823 de de FW 824 828 novo novo FW 829 831 on on IN 832 849 transcriptionally transcriptionally RB 850 858 inactive inactive JJ 859 866 alleles allele NNS 867 869 in in IN 870 881 established established JJ 882 886 cell cell NN 887 892 lines line NNS 892 893 . . . 894 898 Five five CD 899 904 major major JJ 905 912 DNase-I DNase-I NNP 913 927 hypersensitive hypersensitive JJ 928 933 sites site NNS 934 935 ( ( ( 935 937 HS HS NNP 937 938 ) ) ) 939 943 were be VBD 944 950 mapped map VBN 951 953 in in IN 954 957 the the DT 958 963 tal-1 tal-1 NN 964 969 locus locus NN 969 970 . . . 971 973 HS HS NNP 974 975 I i CD 975 976 , , , 977 979 IV iv CD 979 980 , , , 981 984 and and CC 985 986 V V NNP 987 991 were be VBD 992 1003 exclusively exclusively RB 1004 1012 observed observe VBN 1013 1015 in in IN 1016 1019 the the DT 1020 1044 erythroid/megakaryocytic erythroid/megakaryocytic JJ 1045 1049 cell cell NN 1050 1055 lines line NNS 1056 1060 that that WDT 1061 1068 express express VBP 1069 1074 tal-1 tal-1 NN 1075 1079 from from IN 1080 1083 the the DT 1084 1093 promoters promoter NNS 1094 1096 1a 1a NN 1097 1100 and and CC 1101 1104 1b. 1b. CD 1105 1107 HS HS NNP 1108 1110 II ii CD 1111 1114 was be VBD 1115 1119 weak weak JJ 1120 1122 in in IN 1123 1136 hematopoietic hematopoietic JJ 1137 1141 cell cell NN 1142 1147 lines line NNS 1147 1148 , , , 1149 1155 absent absent JJ 1156 1158 in in IN 1159 1163 Hela Hela NNP 1163 1164 , , , 1165 1168 and and CC 1169 1176 greatly greatly RB 1177 1185 enhanced enhance VBN 1186 1188 in in IN 1189 1195 Jurkat Jurkat NNP 1195 1196 , , , 1197 1207 suggesting suggest VBG 1208 1212 that that IN 1213 1217 this this DT 1218 1224 region region NN 1225 1230 might might MD 1231 1233 be be VB 1234 1244 implicated implicate VBN 1245 1247 in in IN 1248 1251 the the DT 1252 1266 cis-activation cis-activation NN 1267 1269 of of IN 1270 1275 tal-1 tal-1 NN 1276 1284 promoter promoter NN 1285 1287 1b 1b NN 1288 1290 in in IN 1291 1295 this this DT 1296 1300 cell cell NN 1301 1305 line line NN 1305 1306 . . . 1307 1309 HS HS NNP 1310 1313 III iii CD 1314 1317 was be VBD 1318 1322 weak weak JJ 1323 1325 in in IN 1326 1329 HEL HEL NNP 1330 1333 and and CC 1334 1340 Jurkat Jurkat NNP 1340 1341 , , , 1342 1345 and and CC 1346 1353 greatly greatly RB 1354 1362 enhanced enhance VBN 1363 1365 in in IN 1366 1371 DU528 du528 NN 1371 1372 , , , 1373 1374 a a DT 1375 1381 T-cell t-cell NN 1382 1386 line line NN 1387 1391 that that WDT 1392 1397 bears bear VBZ 1398 1399 a a DT 1400 1401 t t NN 1402 1403 ( ( ( 1403 1407 1;14 1;14 CD 1407 1408 ) ) ) 1409 1412 and and CC 1413 1422 initiates initiate VBZ 1423 1428 tal-1 tal-1 NN 1429 1442 transcription transcription NN 1443 1449 within within IN 1450 1454 exon exon NN 1455 1456 4 4 CD 1456 1457 . . . 1458 1463 These these DT 1464 1471 results result NNS 1472 1479 suggest suggest VBP 1480 1484 that that IN 1485 1493 distinct distinct JJ 1494 1504 regulatory regulatory JJ 1505 1513 elements element NNS 1514 1517 are be VBP 1518 1528 associated associate VBN 1529 1533 with with IN 1534 1537 the the DT 1538 1541 use use NN 1542 1544 of of IN 1545 1548 the the DT 1549 1558 different different JJ 1559 1564 tal-1 tal-1 NN 1565 1574 promoters promoter NNS 1574 1575 . . .