0 4 TAL1 tal1 NN 5 8 and and CC 9 17 LIM-only lim-only JJ 18 26 proteins protein NNS 27 42 synergistically synergistically RB 43 49 induce induce VBP 50 63 retinaldehyde retinaldehyde NN 64 77 dehydrogenase dehydrogenase NN 78 79 2 2 CD 80 90 expression expression NN 91 93 in in IN 94 100 T-cell t-cell NN 101 106 acute acute JJ 107 120 lymphoblastic lymphoblastic JJ 121 129 leukemia leukemia NN 130 132 by by IN 133 139 acting act VBG 140 142 as as IN 143 152 cofactors cofactor NNS 153 156 for for IN 157 162 GATA3 GATA3 NNP 162 163 . . . 165 175 Previously previously RB 175 176 , , , 177 179 we we PRP 180 184 have have VBP 185 190 shown show VBN 191 195 that that IN 196 200 TAL1 TAL1 NNP 201 204 and and CC 205 208 the the DT 209 217 LIM-only lim-only JJ 218 225 protein protein NN 226 230 gene gene NN 231 232 ( ( ( 232 235 LMO LMO NNP 235 236 ) ) ) 237 240 are be VBP 241 250 regularly regularly RB 251 262 coactivated coactivate VBN 263 265 in in IN 266 272 T-cell t-cell NN 273 278 acute acute JJ 279 292 lymphoblastic lymphoblastic JJ 293 301 leukemia leukemia NN 302 303 ( ( ( 303 308 T-ALL T-ALL NNP 308 309 ) ) ) 309 310 . . . 311 315 This this DT 316 327 observation observation NN 328 330 is be VBZ 331 337 likely likely JJ 338 340 to to TO 341 347 relate relate VB 348 350 to to TO 351 354 the the DT 355 363 findings finding NNS 364 368 that that IN 369 373 TAL1 TAL1 NNP 374 377 and and CC 378 381 LMO LMO NNP 382 385 are be VBP 386 392 highly highly RB 393 404 synergistic synergistic JJ 405 407 in in IN 408 414 T-cell t-cell NN 415 428 tumorigenesis tumorigenesis NN 429 431 in in IN 432 449 double-transgenic double-transgenic JJ 450 454 mice mouse NNS 454 455 . . . 456 458 To to TO 459 469 understand understand VB 470 473 the the DT 474 483 molecular molecular JJ 484 494 mechanisms mechanism NNS 495 497 of of IN 498 508 functional functional JJ 509 516 synergy synergy NN 517 524 between between IN 525 529 TAL1 TAL1 NNP 530 533 and and CC 534 537 LMO LMO NNP 538 540 in in IN 541 554 tumorigenesis tumorigenesis NN 555 558 and and CC 559 574 transcriptional transcriptional JJ 575 585 regulation regulation NN 585 586 , , , 587 589 we we PRP 590 595 tried try VBD 596 598 to to TO 599 607 identify identify VB 608 618 downstream downstream JJ 619 625 target target NN 626 631 genes gene NNS 632 641 regulated regulate VBN 642 644 by by IN 645 649 TAL1 TAL1 NNP 650 653 and and CC 654 657 LMO LMO NNP 658 660 by by IN 661 662 a a DT 663 674 subtractive subtractive JJ 675 678 PCR pcr NN 679 685 method method NN 685 686 . . . 687 690 One one CD 691 693 of of IN 694 697 the the DT 698 706 isolated isolate VBN 707 712 genes gene NNS 712 713 , , , 714 718 that that IN 719 722 for for IN 723 736 retinaldehyde retinaldehyde NN 737 750 dehydrogenase dehydrogenase NN 751 752 2 2 CD 753 754 ( ( ( 754 760 RALDH2 raldh2 NN 760 761 ) ) ) 761 762 , , , 763 766 was be VBD 767 776 regularly regularly RB 777 786 expressed express VBN 787 789 in in IN 790 794 most most JJS 795 797 of of IN 798 801 the the DT 802 807 T-ALL T-ALL NNP 808 812 cell cell NN 813 818 lines line NNS 819 823 that that WDT 824 835 coexpressed coexpresse VBD 836 840 TAL1 tal1 NN 841 844 and and CC 845 848 LMO LMO NNP 848 849 . . . 850 861 Exogenously exogenously RB 862 873 transfected transfecte VBN 874 878 TAL1 TAL1 NNP 879 882 and and CC 883 886 LMO LMO NNP 886 887 , , , 888 891 but but CC 892 895 not not RB 896 902 either either DT 903 908 alone alone RB 908 909 , , , 910 917 induced induce VBD 918 924 RALDH2 raldh2 NN 925 935 expression expression NN 936 938 in in IN 939 940 a a DT 941 946 T-ALL T-ALL NNP 947 951 cell cell NN 952 956 line line NN 956 957 , , , 958 965 HPB-ALL HPB-ALL NNP 965 966 , , , 967 970 not not RB 971 981 expressing express VBG 982 993 endogeneous endogeneous JJ 994 998 TAL1 tal1 NN 999 1001 or or CC 1002 1005 LMO LMO NNP 1005 1006 . . . 1007 1010 The the DT 1011 1017 RALDH2 raldh2 NN 1018 1029 transcripts transcript NNS 1030 1032 in in IN 1033 1038 T-ALL T-ALL NNP 1039 1043 were be VBD 1043 1044 , , , 1045 1052 however however RB 1052 1053 , , , 1054 1060 mostly mostly RB 1061 1070 initiated initiate VBN 1071 1077 within within IN 1078 1081 the the DT 1082 1088 second second JJ 1089 1095 intron intron NN 1095 1096 . . . 1097 1105 Promoter promoter NN 1106 1114 analysis analysis NN 1115 1123 revealed reveal VBD 1124 1128 that that IN 1129 1130 a a DT 1131 1135 GATA GATA NNP 1136 1140 site site NN 1141 1143 in in IN 1144 1145 a a DT 1146 1153 cryptic cryptic JJ 1154 1162 promoter promoter NN 1163 1165 in in IN 1166 1169 the the DT 1170 1176 second second JJ 1177 1183 intron intron NN 1184 1187 was be VBD 1188 1197 essential essential JJ 1198 1201 and and CC 1202 1212 sufficient sufficient JJ 1213 1216 for for IN 1217 1220 the the DT 1221 1226 TAL1- TAL1- NNP 1227 1230 and and CC 1231 1244 LMO-dependent lmo-dependent JJ 1245 1260 transcriptional transcriptional JJ 1261 1271 activation activation NN 1271 1272 , , , 1273 1276 and and CC 1277 1282 GATA3 gata3 NN 1283 1288 binds bind VBZ 1289 1291 to to TO 1292 1296 this this DT 1297 1301 site site NN 1301 1302 . . . 1303 1305 In in IN 1306 1314 addition addition NN 1314 1315 , , , 1316 1322 forced force VBN 1323 1333 expression expression NN 1334 1336 of of IN 1337 1342 GATA3 gata3 NN 1343 1354 potentiated potentiate VBD 1355 1358 the the DT 1359 1368 induction induction NN 1369 1371 of of IN 1372 1378 RALDH2 raldh2 NN 1379 1381 by by IN 1382 1386 TAL1 TAL1 NNP 1387 1390 and and CC 1391 1394 LMO LMO NNP 1394 1395 , , , 1396 1399 and and CC 1400 1405 these these DT 1406 1411 three three CD 1412 1419 factors factor NNS 1420 1426 formed form VBD 1427 1428 a a DT 1429 1436 complex complex NN 1437 1439 in in FW 1440 1444 vivo vivo FW 1444 1445 . . . 1446 1457 Furthermore furthermore RB 1457 1458 , , , 1459 1460 a a DT 1461 1465 TAL1 tal1 NN 1466 1472 mutant mutant NN 1473 1476 not not RB 1477 1484 binding bind VBG 1485 1487 to to TO 1488 1491 DNA DNA NNP 1492 1496 also also RB 1497 1506 activated activate VBD 1507 1510 the the DT 1511 1524 transcription transcription NN 1525 1527 of of IN 1528 1534 RALDH2 raldh2 NN 1535 1537 in in IN 1538 1541 the the DT 1542 1550 presence presence NN 1551 1553 of of IN 1554 1557 LMO LMO NNP 1558 1561 and and CC 1562 1567 GATA3 GATA3 NNP 1567 1568 . . . 1569 1581 Collectively collectively RB 1581 1582 , , , 1583 1585 we we PRP 1586 1590 have have VBP 1591 1601 identified identify VBN 1602 1605 the the DT 1606 1612 RALDH2 raldh2 NN 1613 1617 gene gene NN 1618 1620 as as IN 1621 1622 a a DT 1623 1628 first first JJ 1629 1636 example example NN 1637 1639 of of IN 1640 1646 direct direct JJ 1647 1662 transcriptional transcriptional JJ 1663 1669 target target NN 1670 1675 genes gene NNS 1676 1685 regulated regulate VBN 1686 1688 by by IN 1689 1693 TAL1 TAL1 NNP 1694 1697 and and CC 1698 1701 LMO LMO NNP 1702 1704 in in IN 1705 1710 T-ALL T-ALL NNP 1710 1711 . . . 1712 1714 In in IN 1715 1719 this this DT 1720 1724 case case NN 1724 1725 , , , 1726 1730 TAL1 TAL1 NNP 1731 1734 and and CC 1735 1738 LMO LMO NNP 1739 1742 act act VBP 1743 1745 as as IN 1746 1755 cofactors cofactor NNS 1756 1759 for for IN 1760 1765 GATA3 gata3 NN 1766 1768 to to TO 1769 1777 activate activate VB 1778 1781 the the DT 1782 1795 transcription transcription NN 1796 1798 of of IN 1799 1805 RALDH2 raldh2 NN 1805 1806 . . .