0 15 Transcriptional transcriptional JJ 16 31 down-regulation down-regulation NN 32 34 of of IN 35 40 c-myc c-myc NN 41 51 expression expression NN 52 54 by by IN 55 62 protein protein NN 63 82 synthesis-dependent synthesis-dependent JJ 83 86 and and CC 87 99 -independent -independent JJ 100 108 pathways pathway NNS 109 111 in in IN 112 113 a a DT 114 119 human human JJ 120 121 T t NN 122 135 lymphoblastic lymphoblastic JJ 136 141 tumor tumor NN 142 146 cell cell NN 147 151 line line NN 151 152 . . . 154 156 We we PRP 157 161 show show VBP 162 166 that that IN 167 169 in in IN 170 173 the the DT 174 179 human human JJ 180 181 T t NN 182 195 lymphoblastic lymphoblastic JJ 196 201 tumor tumor NN 202 206 cell cell NN 207 211 line line NN 212 217 Molt4 molt4 NN 218 223 c-myc c-myc NN 224 228 mRNA mrna NN 229 232 and and CC 233 240 protein protein NN 241 251 expression expression NN 252 254 is be VBZ 255 269 down-regulated down-regulate VBN 270 275 after after IN 276 284 exposure exposure NN 285 287 to to TO 288 296 dimethyl dimethyl NN 297 306 sulfoxide sulfoxide NN 306 307 , , , 308 310 to to TO 311 318 phorbol phorbol NN 319 328 myristate myristate NN 329 336 acetate acetate NN 336 337 , , , 338 340 or or CC 341 343 to to TO 344 347 the the DT 348 355 calcium calcium NN 356 365 ionophore ionophore NN 366 372 A23187 a23187 NN 372 373 , , , 374 379 which which WDT 380 386 raises raise VBZ 387 390 the the DT 391 404 intracellular intracellular JJ 405 412 calcium calcium NN 413 426 concentration concentration NN 426 427 . . . 428 429 A a DT 430 435 block block NN 436 438 to to TO 439 442 RNA RNA NNP 443 453 elongation elongation NN 454 456 is be VBZ 457 464 largely largely RB 465 476 responsible responsible JJ 477 480 for for IN 481 490 decreased decrease VBN 491 496 c-myc c-myc NN 497 510 transcription transcription NN 510 511 . . . 512 520 Although although IN 521 529 negative negative JJ 530 540 regulation regulation NN 541 543 by by IN 544 552 dimethyl dimethyl NN 553 562 sulfoxide sulfoxide NN 563 568 takes take VBZ 569 574 place place NN 575 579 even even RB 580 584 when when WRB 585 592 protein protein NN 593 602 synthesis synthesis NN 603 605 is be VBZ 606 615 inhibited inhibit VBN 616 618 by by IN 619 632 cycloheximide cycloheximide NN 632 633 , , , 634 637 the the DT 638 645 phorbol phorbol NN 646 655 myristate myristate NN 656 663 acetate acetate NN 664 670 effect effect NN 671 673 is be VBZ 674 681 blocked block VBN 682 684 to to TO 685 689 some some DT 690 696 extent extent NN 697 701 only only RB 702 704 by by IN 705 718 cycloheximide cycloheximide NN 718 719 . . . 720 723 The the DT 724 731 calcium calcium NN 732 749 ionophore-induced ionophore-induced JJ 750 755 c-myc c-myc NN 756 767 suppression suppression NN 767 768 , , , 769 776 however however RB 776 777 , , , 778 786 strictly strictly RB 787 795 requires require VBZ 796 798 de de FW 799 803 novo novo FW 804 811 protein protein NN 812 821 synthesis synthesis NN 821 822 . . . 823 832 Therefore therefore RB 832 833 , , , 834 837 two two CD 838 847 different different JJ 848 856 negative negative JJ 857 867 regulatory regulatory JJ 868 876 pathways pathway NNS 877 880 are be VBP 881 889 involved involve VBN 890 892 in in IN 893 898 c-myc c-myc NN 899 909 regulation regulation NN 909 910 : : : 911 914 one one CD 915 920 which which WDT 921 923 is be VBZ 924 935 independent independent JJ 936 939 and and CC 940 943 one one CD 944 949 which which WDT 950 957 depends depend VBZ 958 960 on on IN 961 963 de de FW 964 968 novo novo FW 969 976 protein protein NN 977 986 synthesis synthesis NN 986 987 . . . 988 991 The the DT 992 998 latter latter JJ 999 1002 one one NN 1003 1010 appears appear VBZ 1011 1013 to to TO 1014 1016 be be VB 1017 1025 mediated mediate VBN 1026 1028 by by IN 1029 1030 a a DT 1031 1038 rapidly rapidly RB 1039 1056 calcium-dependent calcium-dependent JJ 1057 1064 induced induce VBN 1065 1069 gene gene NN 1070 1077 product product NN 1077 1078 . . .