0 5 Steel Steel NNP 6 12 factor factor NN 13 20 affects affect VBZ 21 24 SCL scl NN 25 35 expression expression NN 36 42 during during IN 43 49 normal normal JJ 50 59 erythroid erythroid JJ 60 75 differentiation differentiation NN 75 76 . . . 78 83 Steel Steel NNP 84 90 factor factor NN 91 93 is be VBZ 94 97 one one CD 98 100 of of IN 101 104 the the DT 105 111 growth growth NN 112 119 factors factor NNS 120 124 that that WDT 125 133 controls control VBZ 134 137 the the DT 138 151 proliferation proliferation NN 152 155 and and CC 156 171 differentiation differentiation NN 172 174 of of IN 175 188 hematopoietic hematopoietic JJ 189 194 cells cell NNS 195 198 and and CC 199 202 SCL SCL NNP 202 203 , , , 204 208 also also RB 209 214 known know VBN 215 217 as as IN 218 223 Tcl-5 Tcl-5 NNP 224 226 or or CC 227 232 Tal-1 Tal-1 NNP 232 233 , , , 234 236 is be VBZ 237 238 a a DT 239 252 transcription transcription NN 253 259 factor factor NN 260 268 involved involve VBN 269 271 in in IN 272 286 erythropoiesis erythropoiesis NN 286 287 . . . 288 290 In in IN 291 295 this this DT 296 302 report report NN 302 303 , , , 304 306 we we PRP 307 314 studied study VBD 315 318 the the DT 319 323 role role NN 324 326 of of IN 327 330 SCL SCL NNP 331 333 in in IN 334 337 the the DT 338 351 proliferation proliferation NN 352 354 of of IN 355 360 human human JJ 361 371 peripheral peripheral JJ 372 377 blood blood NN 378 391 burst-forming burst-forming JJ 392 406 unit-erythroid unit-erythroid JJ 407 408 ( ( ( 408 413 BFU-E BFU-E NNP 413 414 ) ) ) 415 418 and and CC 419 422 the the DT 423 430 effects effect NNS 431 433 of of IN 434 439 Steel Steel NNP 440 446 factor factor NN 447 449 on on IN 450 453 SCL SCL NNP 454 464 expression expression NN 465 467 in in IN 468 481 proliferating proliferate VBG 482 491 erythroid erythroid JJ 492 497 cells cell NNS 497 498 . . . 499 512 BFU-E-derived bfu-e-derived JJ 513 521 colonies colony NNS 522 530 increase increase VBP 531 544 progressively progressively RB 545 547 in in IN 548 552 size size NN 552 553 , , , 554 556 as as IN 557 567 determined determine VBN 568 570 by by IN 571 575 cell cell NN 576 582 number number NN 582 583 , , , 584 588 from from IN 589 592 day day NN 593 594 7 7 CD 595 597 to to TO 598 601 day day NN 602 604 14 14 CD 605 607 of of IN 608 615 culture culture NN 615 616 , , , 617 621 with with IN 622 625 the the DT 626 634 greatest great JJS 635 643 increase increase NN 644 646 in in IN 647 653 colony colony NN 654 658 size size NN 659 660 ( ( ( 660 667 10-fold 10-fold JJ 668 677 expansion expansion NN 677 678 ) ) ) 679 688 occurring occur VBG 689 696 between between IN 697 700 day day NN 701 702 7 7 CD 703 706 and and CC 707 710 day day NN 711 713 10 10 CD 713 714 . . . 715 718 SCL SCL NNP 719 726 protein protein NN 727 733 levels level NNS 734 736 in in IN 737 750 BFU-E-derived bfu-e-derived JJ 751 756 cells cell NNS 757 761 were be VBD 762 769 highest high JJS 770 772 in in IN 773 776 day day NN 777 778 7 7 CD 779 784 cells cell NNS 785 788 and and CC 789 798 decreased decrease VBD 799 812 progressively progressively RB 813 817 from from IN 818 821 day day NN 822 823 7 7 CD 824 826 to to TO 827 830 day day NN 831 833 14 14 CD 834 836 of of IN 837 844 culture culture NN 844 845 , , , 846 856 suggesting suggest VBG 857 859 an an DT 860 871 association association NN 872 874 of of IN 875 878 SCL SCL NNP 879 883 with with IN 884 893 erythroid erythroid JJ 894 907 proliferation proliferation NN 907 908 . . . 909 911 In in IN 912 920 contrast contrast NN 920 921 , , , 922 925 SCL SCL NNP 926 930 mRNA mRNA NNP 931 937 levels level NNS 938 941 did do VBD 942 945 not not RB 946 954 decrease decrease VB 955 968 significantly significantly RB 969 976 between between IN 977 980 day day NN 981 982 7 7 CD 983 986 and and CC 987 990 day day NN 991 993 14 14 CD 994 999 cells cell NNS 999 1000 , , , 1001 1011 suggesting suggest VBG 1012 1016 that that IN 1017 1036 posttranscriptional posttranscriptional JJ 1037 1047 mechanisms mechanism NNS 1048 1051 are be VBP 1052 1059 largely largely RB 1060 1071 responsible responsible JJ 1072 1075 for for IN 1076 1079 the the DT 1080 1088 decrease decrease NN 1089 1091 in in IN 1092 1095 SCL SCL NNP 1096 1103 protein protein NN 1104 1112 observed observe VBN 1112 1113 . . . 1114 1117 The the DT 1118 1122 role role NN 1123 1125 of of IN 1126 1129 SCL SCL NNP 1130 1132 in in IN 1133 1138 Steel Steel NNP 1139 1153 factor-induced factor-induced JJ 1154 1163 erythroid erythroid JJ 1164 1177 proliferation proliferation NN 1178 1181 was be VBD 1182 1186 then then RB 1187 1195 examined examine VBN 1195 1196 . . . 1197 1199 In in IN 1200 1213 BFU-E-derived bfu-e-derived JJ 1214 1222 colonies colony NNS 1223 1231 cultured culture VBN 1232 1236 with with IN 1237 1242 Steel Steel NNP 1243 1249 factor factor NN 1249 1250 , , , 1251 1257 colony colony NN 1258 1262 size size NN 1263 1266 was be VBD 1267 1280 significantly significantly RB 1281 1290 increased increase VBN 1291 1299 compared compare VBN 1300 1302 to to TO 1303 1310 control control NN 1310 1311 . . . 1312 1314 In in IN 1315 1318 day day NN 1319 1320 7 7 CD 1321 1324 and and CC 1325 1328 day day NN 1329 1331 10 10 CD 1332 1341 erythroid erythroid JJ 1342 1352 precursors precursor NNS 1353 1361 cultured culture VBN 1362 1366 with with IN 1367 1372 Steel Steel NNP 1373 1379 factor factor NN 1379 1380 , , , 1381 1384 SCL SCL NNP 1385 1392 protein protein NN 1393 1396 was be VBD 1397 1406 increased increase VBN 1407 1420 significantly significantly RB 1421 1429 compared compare VBN 1430 1432 to to TO 1433 1440 control control NN 1440 1441 . . . 1442 1445 The the DT 1446 1454 increase increase NN 1455 1457 in in IN 1458 1461 SCL SCL NNP 1462 1469 protein protein NN 1470 1476 levels level NNS 1477 1479 in in IN 1480 1485 early early JJ 1486 1495 erythroid erythroid JJ 1496 1506 precursors precursor NNS 1507 1517 stimulated stimulate VBN 1518 1522 with with IN 1523 1528 Steel Steel NNP 1529 1535 factor factor NN 1536 1544 suggests suggest VBZ 1545 1548 one one CD 1549 1558 mechanism mechanism NN 1559 1566 through through IN 1567 1572 which which WDT 1573 1578 Steel Steel NNP 1579 1585 factor factor NN 1586 1589 may may MD 1590 1597 enhance enhance VB 1598 1604 normal normal JJ 1605 1614 erythroid erythroid JJ 1615 1628 proliferation proliferation NN 1628 1629 . . . 1630 1633 SCL SCL NNP 1634 1638 mRNA mRNA NNP 1639 1645 levels level NNS 1646 1654 assessed assess VBN 1655 1657 by by IN 1658 1666 Northern northern JJ 1667 1671 blot blot NN 1672 1674 in in IN 1675 1678 day day NN 1679 1680 7 7 CD 1681 1686 cells cell NNS 1687 1690 did do VBD 1691 1694 not not RB 1695 1703 increase increase VB 1704 1717 significantly significantly RB 1718 1720 in in IN 1721 1729 response response NN 1730 1732 to to TO 1733 1738 Steel Steel NNP 1739 1745 factor factor NN 1746 1757 stimulation stimulation NN 1757 1758 , , , 1759 1769 suggesting suggest VBG 1770 1774 that that IN 1775 1794 posttranscriptional posttranscriptional JJ 1795 1805 mechanisms mechanism NNS 1806 1809 may may MD 1810 1814 also also RB 1815 1817 be be VB 1818 1827 important important JJ 1828 1830 in in IN 1831 1834 the the DT 1835 1843 increase increase NN 1844 1846 in in IN 1847 1850 SCL SCL NNP 1851 1858 protein protein NN 1859 1867 observed observe VBN 1868 1870 in in IN 1871 1879 response response NN 1880 1882 to to TO 1883 1888 Steel Steel NNP 1888 1889 . . .