0 4 AML1 AML1 NNP 5 6 ( ( ( 6 15 CBFalpha2 cbfalpha2 NN 15 16 ) ) ) 17 27 cooperates cooperate VBZ 28 32 with with IN 33 34 B B NNP 35 48 cell-specific cell-specific JJ 49 59 activating activate VBG 60 67 protein protein NN 68 69 ( ( ( 69 78 BSAP/PAX5 BSAP/PAX5 NNP 78 79 ) ) ) 80 82 in in IN 83 93 activation activation NN 94 96 of of IN 97 100 the the DT 101 102 B B NNP 103 116 cell-specific cell-specific JJ 117 120 BLK BLK NNP 121 125 gene gene NN 126 134 promoter promoter NN 134 135 . . . 137 141 AML1 AML1 NNP 142 147 plays play VBZ 148 149 a a DT 150 158 critical critical JJ 159 163 role role NN 164 170 during during IN 171 184 hematopoiesis hematopoiesis NN 185 188 and and CC 189 200 chromosomal chromosomal JJ 201 215 translocations translocation NNS 216 225 involving involve VBG 226 230 AML1 aml1 NN 231 234 are be VBP 235 243 commonly commonly RB 244 254 associated associate VBN 255 259 with with IN 260 269 different different JJ 270 275 forms form NNS 276 278 of of IN 279 287 leukemia leukemia NN 287 288 , , , 289 298 including include VBG 299 304 pre-B pre-b JJ 305 310 acute acute JJ 311 324 lymphoblastic lymphoblastic JJ 325 333 leukemia leukemia NN 333 334 . . . 335 337 To to TO 338 348 understand understand VB 349 352 the the DT 353 361 function function NN 362 364 of of IN 365 369 AML1 AML1 NNP 370 376 during during IN 377 378 B B NNP 379 383 cell cell NN 384 399 differentiation differentiation NN 399 400 , , , 401 403 we we PRP 404 412 analyzed analyze VBD 413 423 regulatory regulatory JJ 424 431 regions region NNS 432 434 of of IN 435 436 B B NNP 437 450 cell-specific cell-specific JJ 451 456 genes gene NNS 457 460 for for IN 461 470 potential potential JJ 471 483 AML1-binding aml1-binding JJ 484 489 sites site NNS 490 493 and and CC 494 498 have have VBP 499 509 identified identify VBN 510 511 a a DT 512 520 putative putative JJ 521 533 AML1-binding aml1-binding JJ 534 538 site site NN 539 541 in in IN 542 545 the the DT 546 554 promoter promoter NN 555 557 of of IN 558 561 the the DT 562 563 B B NNP 564 577 cell-specific cell-specific JJ 578 586 tyrosine tyrosine NN 587 593 kinase kinase NNP 594 598 gene gene NN 598 599 , , , 600 603 blk blk NN 603 604 . . . 605 608 Gel Gel NNP 609 617 mobility mobility NN 618 623 shift shift NN 624 630 assays assay NNS 631 634 and and CC 635 644 transient transient JJ 645 657 transfection transfection NN 658 664 assays assay NNS 665 676 demonstrate demonstrate VBP 677 681 that that IN 682 686 AML1 aml1 NN 687 692 binds bind VBZ 693 705 specifically specifically RB 706 708 to to TO 709 713 this this DT 714 718 site site NN 719 721 in in IN 722 725 the the DT 726 729 blk blk NN 730 738 promoter promoter NN 739 742 and and CC 743 747 this this DT 748 755 binding bind VBG 756 760 site site NN 761 763 is be VBZ 764 773 important important JJ 774 777 for for IN 778 781 blk blk NN 782 790 promoter promoter NN 791 799 activity activity NN 799 800 . . . 801 812 Furthermore furthermore RB 812 813 , , , 814 816 in in FW 817 822 vitro vitro FW 823 830 binding binding NN 831 839 analysis analysis NN 840 848 revealed reveal VBD 849 853 that that IN 854 857 the the DT 858 862 AML1 aml1 NN 863 867 runt runt NN 868 879 DNA-binding dna-binding JJ 880 886 domain domain NN 887 897 physically physically RB 898 907 interacts interact VBZ 908 912 with with IN 913 916 the the DT 917 923 paired paired JJ 924 935 DNA-binding dna-binding JJ 936 942 domain domain NN 943 945 of of IN 946 950 BSAP BSAP NNP 950 951 , , , 952 953 a a DT 954 955 B B NNP 956 969 cell-specific cell-specific JJ 970 983 transcription transcription NN 984 990 factor factor NN 990 991 . . . 992 996 BSAP BSAP NNP 997 1000 has have VBZ 1001 1005 been be VBN 1006 1011 shown show VBN 1012 1022 previously previously RB 1023 1025 to to TO 1026 1028 be be VB 1029 1038 important important JJ 1039 1042 for for IN 1043 1044 B B NNP 1045 1058 cell-specific cell-specific JJ 1059 1069 regulation regulation NN 1070 1072 of of IN 1073 1076 the the DT 1077 1080 blk blk NN 1081 1085 gene gene NN 1085 1086 . . . 1087 1095 Physical physical JJ 1096 1107 interaction interaction NN 1108 1110 of of IN 1111 1115 AML1 AML1 NNP 1116 1120 with with IN 1121 1125 BSAP BSAP NNP 1126 1136 correlates correlate VBZ 1137 1141 with with IN 1142 1152 functional functional JJ 1153 1166 cooperativity cooperativity NN 1167 1169 in in IN 1170 1182 transfection transfection NN 1183 1190 studies study NNS 1191 1196 where where WRB 1197 1201 AML1 AML1 NNP 1202 1205 and and CC 1206 1210 BSAP BSAP NNP 1211 1226 synergistically synergistically RB 1227 1235 activate activate VBP 1236 1239 blk blk NN 1240 1248 promoter promoter NN 1249 1262 transcription transcription NN 1263 1265 by by IN 1266 1270 more more JJR 1271 1275 than than IN 1276 1283 50-fold 50-fold JJ 1283 1284 . . . 1285 1290 These these DT 1291 1298 results result NNS 1299 1310 demonstrate demonstrate VBP 1311 1319 physical physical JJ 1320 1323 and and CC 1324 1334 functional functional JJ 1335 1347 interactions interaction NNS 1348 1355 between between IN 1356 1360 AML1 AML1 NNP 1361 1364 and and CC 1365 1369 BSAP BSAP NNP 1370 1373 and and CC 1374 1381 suggest suggest VBP 1382 1386 that that IN 1387 1391 AML1 aml1 NN 1392 1394 is be VBZ 1395 1397 an an DT 1398 1407 important important JJ 1408 1414 factor factor NN 1415 1418 for for IN 1419 1429 regulating regulate VBG 1430 1431 a a DT 1432 1440 critical critical JJ 1441 1442 B B NNP 1443 1456 cell-specific cell-specific JJ 1457 1461 gene gene NN 1461 1462 , , , 1463 1466 blk blk NN 1466 1467 . . .