0 10 Regulation regulation NN 11 13 of of IN 14 19 c-jun c-jun NN 20 24 mRNA mrna NN 25 35 expression expression NN 36 38 by by IN 39 50 hydroxyurea hydroxyurea NN 51 53 in in IN 54 59 human human JJ 60 64 K562 k562 NN 65 70 cells cell NNS 71 77 during during IN 78 87 erythroid erythroid JJ 88 103 differentiation differentiation NN 104 105 [ [ ( 105 114 published publish VBN 115 122 erratum erratum NN 123 130 appears appear VBZ 131 133 in in IN 134 141 Biochim Biochim NNP 142 149 Biophys Biophys NNP 150 154 Acta Acta NNP 155 159 1995 1995 CD 160 163 Dec Dec NNP 164 178 27;1264(3):409 27;1264(3):409 CD 178 179 ] ] ) 181 192 Hydroxyurea Hydroxyurea NNP 193 194 ( ( ( 194 196 HU HU NNP 196 197 ) ) ) 198 200 is be VBZ 201 203 an an DT 204 213 antitumor antitumor JJ 214 219 agent agent NN 220 225 which which WDT 226 230 also also RB 231 238 induces induce VBZ 239 256 hemoglobinization hemoglobinization NN 257 263 during during IN 264 273 erythroid erythroid JJ 274 289 differentiation differentiation NN 289 290 . . . 291 293 In in IN 294 302 addition addition NN 302 303 , , , 304 306 HU hu NN 307 317 stimulates stimulate VBZ 318 321 the the DT 322 331 synthesis synthesis NN 332 334 of of IN 335 340 fetal fetal JJ 341 351 hemoglobin hemoglobin NN 352 354 in in IN 355 361 sickle sickle JJ 362 366 cell cell NN 367 373 anemia anemia NN 374 382 patients patient NNS 382 383 . . . 384 386 To to TO 387 394 further further RB 395 405 understand understand VB 406 409 its its PRP$ 410 419 mechanism mechanism NN 420 422 of of IN 423 429 action action NN 429 430 , , , 431 433 we we PRP 434 446 investigated investigate VBD 447 450 the the DT 451 458 effects effect NNS 459 461 of of IN 462 464 HU HU NNP 465 467 on on IN 468 478 regulation regulation NN 479 481 of of IN 482 487 c-jun c-jun NN 488 498 expression expression NN 499 504 prior prior JJ 505 507 to to TO 508 511 the the DT 512 517 onset onset NN 518 520 of of IN 521 530 erythroid erythroid JJ 531 546 differentiation differentiation NN 547 549 of of IN 550 554 K562 k562 NN 555 560 cells cell NNS 560 561 . . . 562 564 HU hu NN 565 572 induced induce VBD 573 574 a a DT 575 589 dose-dependent dose-dependent JJ 590 601 stimulation stimulation NN 602 604 of of IN 605 610 c-jun c-jun NN 611 620 synthesis synthesis NN 620 621 . . . 622 625 The the DT 626 632 levels level NNS 633 635 of of IN 636 641 c-jun c-jun NN 642 646 mRNA mRNA NNP 647 650 was be VBD 651 659 elevated elevate VBN 660 661 4 4 CD 662 664 to to TO 665 673 7.5-fold 7.5-fold RB 674 676 by by IN 677 679 HU HU NNP 680 686 within within IN 687 688 2 2 CD 689 690 h h NN 690 691 . . . 692 696 This this DT 697 700 was be VBD 701 709 followed follow VBN 710 712 by by IN 713 714 a a DT 715 722 gradual gradual JJ 723 730 decline decline NN 731 733 to to TO 734 737 the the DT 738 743 basal basal JJ 744 749 level level NN 750 752 by by IN 753 755 24 24 CD 756 757 h h NN 757 758 . . . 759 763 Both both CC 764 771 nuclear nuclear JJ 772 778 run-on run-on JJ 779 782 and and CC 783 794 actinomycin actinomycin NN 795 796 D D NNP 797 802 pulse pulse NN 803 814 experiments experiment NNS 815 823 strongly strongly RB 824 832 indicate indicate VBP 833 837 that that IN 838 840 HU hu NN 841 850 regulates regulate VBZ 851 856 c-jun c-jun NN 857 861 mRNA mrna NN 862 872 expression expression NN 873 875 by by IN 876 886 increasing increase VBG 887 890 the the DT 891 895 rate rate NN 896 898 of of IN 899 908 synthesis synthesis NN 909 911 as as RB 912 916 well well RB 917 919 as as IN 920 931 stabilizing stabilize VBG 932 935 the the DT 936 941 c-jun c-jun NN 942 946 mRNA mrna NN 946 947 . . . 948 950 In in IN 951 959 addition addition NN 959 960 , , , 961 964 the the DT 965 970 level level NN 971 973 of of IN 974 977 jun jun NN 978 985 protein protein NN 986 989 was be VBD 990 998 elevated elevate VBN 999 1001 by by IN 1002 1003 2 2 CD 1004 1006 to to TO 1007 1013 5-fold 5-fold JJ 1014 1020 within within IN 1021 1022 4 4 CD 1023 1024 h h NN 1025 1027 in in IN 1028 1030 HU HU NNP 1031 1038 treated treat VBN 1039 1044 cells cell NNS 1044 1045 . . . 1046 1057 Furthermore furthermore RB 1057 1058 , , , 1059 1073 concentrations concentration NNS 1074 1076 of of IN 1077 1079 HU HU NNP 1080 1085 below below IN 1086 1089 250 250 CD 1090 1096 microM microM NNP 1097 1105 slightly slightly RB 1106 1115 increased increase VBD 1116 1119 the the DT 1120 1122 5X 5x NN 1123 1131 AP-1/CAT AP-1/CAT NNP 1132 1140 activity activity NN 1140 1141 . . . 1142 1147 These these DT 1148 1155 results result NNS 1156 1164 strongly strongly RB 1165 1172 suggest suggest VBP 1173 1177 that that IN 1178 1180 HU hu NN 1181 1188 induces induce VBZ 1189 1193 both both CC 1194 1209 transcriptional transcriptional JJ 1210 1213 and and CC 1214 1232 post-transcription post-transcription JJ 1233 1243 regulation regulation NN 1244 1246 of of IN 1247 1252 c-jun c-jun NN 1253 1259 during during IN 1260 1269 erythroid erythroid JJ 1270 1285 differentiation differentiation NN 1285 1286 . . .