0 10 Disruption disruption NN 11 13 of of IN 14 19 alpha alpha NN 20 24 beta beta NN 25 28 but but CC 29 32 not not RB 33 35 of of IN 36 41 gamma gamma NN 42 47 delta delta NN 48 49 T t NN 50 54 cell cell NN 55 66 development development NN 67 69 by by IN 70 84 overexpression overexpression NN 85 87 of of IN 88 91 the the DT 92 108 helix-loop-helix helix-loop-helix JJ 109 116 protein protein NN 117 120 Id3 id3 NN 121 123 in in IN 124 133 committed commit VBN 134 135 T t NN 136 140 cell cell NN 141 152 progenitors progenitor NNS 152 153 . . . 155 163 Enforced enforce VBN 164 174 expression expression NN 175 177 of of IN 178 181 Id3 Id3 NNP 181 182 , , , 183 188 which which WDT 189 192 has have VBZ 193 196 the the DT 197 205 capacity capacity NN 206 208 to to TO 209 216 inhibit inhibit VB 217 221 many many JJ 222 227 basic basic JJ 228 244 helix-loop-helix helix-loop-helix JJ 245 246 ( ( ( 246 250 bHLH bhlh JJ 250 251 ) ) ) 252 265 transcription transcription NN 266 273 factors factor NNS 273 274 , , , 275 277 in in IN 278 283 human human JJ 284 291 CD34(+) cd34(+) JJ 292 305 hematopoietic hematopoietic JJ 306 316 progenitor progenitor NN 317 322 cells cell NNS 323 327 that that WDT 328 332 have have VBP 333 336 not not RB 337 346 undergone undergo VBN 347 348 T t NN 349 353 cell cell NN 354 362 receptor receptor NN 363 364 ( ( ( 364 367 TCR TCR NNP 367 368 ) ) ) 369 373 gene gene NN 374 388 rearrangements rearrangement NNS 389 397 inhibits inhibit VBZ 398 409 development development NN 410 412 of of IN 413 416 the the DT 417 427 transduced transduce VBN 428 433 cells cell NNS 434 438 into into IN 439 447 TCRalpha TCRalpha NNP 448 452 beta beta NN 453 456 and and CC 457 462 gamma gamma NN 463 468 delta delta NN 469 474 cells cell NNS 475 477 in in IN 478 479 a a DT 480 485 fetal fetal JJ 486 492 thymic thymic JJ 493 498 organ organ NN 499 506 culture culture NN 507 508 ( ( ( 508 512 FTOC FTOC NNP 512 513 ) ) ) 513 514 . . . 515 519 Here here RB 520 522 we we PRP 523 531 document document VBP 532 536 that that IN 537 551 overexpression overexpression NN 552 554 of of IN 555 558 Id3 Id3 NNP 558 559 , , , 560 562 in in IN 563 574 progenitors progenitor NNS 575 579 that that WDT 580 584 have have VBP 585 594 initiated initiate VBN 595 598 TCR TCR NNP 599 603 gene gene NN 604 618 rearrangements rearrangement NNS 619 620 ( ( ( 620 625 pre-T pre-t JJ 626 631 cells cell NNS 631 632 ) ) ) 632 633 , , , 634 642 inhibits inhibit VBZ 643 654 development development NN 655 659 into into IN 660 668 TCRalpha TCRalpha NNP 669 673 beta beta NN 674 677 but but CC 678 681 not not RB 682 686 into into IN 687 695 TCRgamma TCRgamma NNP 696 701 delta delta NN 702 703 T t NN 704 709 cells cell NNS 709 710 . . . 711 722 Furthermore furthermore RB 722 723 , , , 724 727 Id3 Id3 NNP 728 735 impedes impede VBZ 736 746 expression expression NN 747 749 of of IN 750 763 recombination recombination NN 764 774 activating activate VBG 775 780 genes gene NNS 781 784 and and CC 785 798 downregulates downregulate VBZ 799 809 pre-Talpha pre-talpha NN 810 814 mRNA mrna NN 814 815 . . . 816 821 These these DT 822 834 observations observation NNS 835 842 suggest suggest VBP 843 851 possible possible JJ 852 862 mechanisms mechanism NNS 863 865 by by IN 866 871 which which WDT 872 875 Id3 id3 NN 876 890 overexpression overexpression NN 891 894 can can MD 895 909 differentially differentially RB 910 916 affect affect VB 917 928 development development NN 929 931 of of IN 932 937 pre-T pre-t JJ 938 943 cells cell NNS 944 948 into into IN 949 957 TCRalpha TCRalpha NNP 958 962 beta beta NN 963 966 and and CC 967 972 gamma gamma NN 973 978 delta delta NN 979 984 cells cell NNS 984 985 . . . 986 988 We we PRP 989 993 also also RB 994 1002 observed observe VBD 1003 1007 that that IN 1008 1012 cell cell NN 1013 1020 surface surface NN 1021 1039 CD4(-)CD8(-)CD3(-) cd4(-)cd8(-)cd3(-) JJ 1040 1045 cells cell NNS 1046 1050 with with IN 1051 1061 rearranged rearrange VBN 1062 1065 TCR TCR NNP 1066 1071 genes gene NNS 1072 1081 developed develop VBN 1082 1086 from from IN 1087 1101 Id3-transduced id3-transduced JJ 1102 1105 but but CC 1106 1109 not not RB 1110 1114 from from IN 1115 1133 control-transduced control-transduced JJ 1134 1139 pre-T pre-t JJ 1140 1145 cells cell NNS 1146 1148 in in IN 1149 1151 an an DT 1152 1156 FTOC FTOC NNP 1156 1157 . . . 1158 1163 These these DT 1164 1169 cells cell NNS 1170 1173 had have VBD 1174 1184 properties property NNS 1185 1187 of of IN 1188 1192 both both CC 1193 1200 natural natural JJ 1201 1207 killer killer NN 1208 1209 ( ( ( 1209 1211 NK NK NNP 1211 1212 ) ) ) 1213 1216 and and CC 1217 1222 pre-T pre-t JJ 1223 1228 cells cell NNS 1228 1229 . . . 1230 1235 These these DT 1236 1244 findings finding NNS 1245 1252 suggest suggest VBP 1253 1257 that that IN 1258 1262 bHLH bhlh JJ 1263 1270 factors factor NNS 1271 1274 are be VBP 1275 1283 required require VBN 1284 1286 to to TO 1287 1294 control control VB 1295 1296 T t NN 1297 1301 cell cell NN 1302 1313 development development NN 1314 1319 after after IN 1320 1323 the the DT 1324 1328 T/NK T/NK NNP 1329 1342 developmental developmental JJ 1343 1353 checkpoint checkpoint NN 1353 1354 . . .