0 3 The the DT 4 18 evolutionarily evolutionarily RB 19 28 conserved conserve VBN 29 37 sequence sequence NN 38 46 upstream upstream RB 47 49 of of IN 50 53 the the DT 54 59 human human JJ 60 62 Ig Ig NNP 63 68 heavy heavy JJ 69 74 chain chain NN 75 76 S S NNP 77 82 gamma gamma NN 83 84 3 3 CD 85 91 region region NN 92 94 is be VBZ 95 97 an an DT 98 107 inducible inducible JJ 108 116 promoter promoter NN 116 117 : : : 118 129 synergistic synergistic JJ 130 140 activation activation NN 141 143 by by IN 144 148 CD40 cd40 NN 149 155 ligand ligand NN 156 159 and and CC 160 164 IL-4 il-4 NN 165 168 via via IN 169 180 cooperative cooperative JJ 181 189 NF-kappa NF-kappa NNP 190 191 B B NNP 192 195 and and CC 196 202 STAT-6 STAT-6 NNP 203 210 binding binding NN 211 216 sites site NNS 216 217 . . . 219 227 Germline Germline NNP 228 229 C C NNP 230 235 gamma gamma NN 236 240 gene gene NN 241 254 transcription transcription NN 255 257 is be VBZ 258 259 a a DT 260 267 crucial crucial JJ 268 273 event event NN 274 276 in in IN 277 280 the the DT 281 288 process process NN 289 293 that that WDT 294 299 leads lead VBZ 300 302 to to TO 303 309 switch switch VB 310 313 DNA dna NN 314 327 recombination recombination NN 328 330 to to TO 331 334 IgG IgG NNP 334 335 , , , 336 339 but but CC 340 343 its its PRP$ 344 354 regulation regulation NN 355 357 in in IN 358 361 the the DT 362 367 human human JJ 368 370 is be VBZ 371 377 poorly poorly RB 378 388 understood understand VBN 388 389 . . . 390 392 We we PRP 393 397 took take VBD 398 407 advantage advantage NN 408 410 of of IN 411 414 our our PRP$ 415 425 monoclonal monoclonal JJ 426 431 model model NN 432 434 of of IN 435 443 germinal germinal JJ 444 450 center center NN 451 452 B B NNP 453 457 cell cell NN 458 473 differentiation differentiation NN 473 474 , , , 475 479 IgM+ igm+ JJ 480 484 IgD+ igd+ JJ 485 490 CL-01 cl-01 NN 491 496 cells cell NNS 496 497 , , , 498 500 to to TO 501 507 define define VB 508 511 the the DT 512 516 role role NN 517 519 of of IN 520 523 the the DT 524 525 I i NN 526 531 gamma gamma NN 532 533 3 3 CD 534 548 evolutionarily evolutionarily RB 549 558 conserved conserve VBN 559 567 sequence sequence NN 568 569 ( ( ( 569 572 ECS ECS NNP 572 573 ) ) ) 574 576 in in IN 577 580 the the DT 581 589 germline germline NN 590 605 transcriptional transcriptional JJ 606 616 activation activation NN 617 619 of of IN 620 623 the the DT 624 629 human human JJ 630 631 C C NNP 632 637 gamma gamma NN 638 639 3 3 CD 640 644 gene gene NN 644 645 . . . 646 649 The the DT 650 651 I i NN 652 657 gamma gamma NN 658 659 3 3 CD 660 663 ECS ecs NN 664 668 lies lie VBZ 669 677 upstream upstream RB 678 680 of of IN 681 684 the the DT 685 690 major major JJ 691 692 I i NN 693 698 gamma gamma NN 699 700 3 3 CD 701 714 transcription transcription NN 715 725 initiation initiation NN 726 730 site site NN 731 734 and and CC 735 743 displays display VBZ 744 748 more more JJR 749 753 than than IN 754 756 90 90 CD 756 757 % % NN 758 766 identity identity NN 767 771 with with IN 772 775 the the DT 776 789 corresponding correspond VBG 790 795 human human JJ 796 797 I i NN 798 803 gamma gamma NN 804 805 1 1 CD 805 806 , , , 807 808 I i NN 809 814 gamma gamma NN 815 816 2 2 CD 816 817 , , , 818 821 and and CC 822 823 I i NN 824 829 gamma gamma NN 830 831 4 4 CD 832 839 regions region NNS 839 840 . . . 841 849 Reporter reporter NN 850 860 luciferase luciferase NN 861 865 gene gene NN 866 873 vectors vector NNS 874 884 containing contain VBG 885 888 the the DT 889 894 human human JJ 895 900 gamma gamma NN 901 902 3 3 CD 903 906 ECS ecs NN 907 911 were be VBD 912 916 used use VBN 917 919 to to TO 920 929 transfect transfect VB 930 935 CL-01 cl-01 NN 936 941 cells cell NNS 941 942 , , , 943 948 which which WDT 949 953 have have VBP 954 958 been be VBN 959 964 shown show VBN 965 967 to to TO 968 975 undergo undergo VB 976 983 Smu–>S Smu–>S NNP 984 989 gamma gamma NN 990 991 3 3 CD 992 995 DNA dna NN 996 1009 recombination recombination NN 1009 1010 , , , 1011 1015 upon upon IN 1016 1026 engagement engagement NN 1027 1029 of of IN 1030 1034 CD40 cd40 NN 1035 1037 by by IN 1038 1042 CD40 CD40 NNP 1043 1049 ligand ligand NN 1050 1051 ( ( ( 1051 1056 CD40L CD40L NNP 1056 1057 ) ) ) 1058 1061 and and CC 1062 1070 exposure exposure NN 1071 1073 to to TO 1074 1078 IL-4 il-4 NN 1078 1079 . . . 1080 1082 In in IN 1083 1088 these these DT 1089 1100 transfected transfecte VBN 1101 1106 CL-01 cl-01 NN 1107 1112 cells cell NNS 1112 1113 , , , 1114 1124 CD40:CD40L CD40:CD40L NNP 1125 1135 engagement engagement NN 1136 1139 and and CC 1140 1148 exposure exposure NN 1149 1151 to to TO 1152 1156 IL-4 il-4 NN 1157 1172 synergistically synergistically RB 1173 1180 induced induce VBD 1181 1186 gamma gamma NN 1187 1188 3 3 CD 1189 1202 ECS-dependent ecs-dependent JJ 1203 1213 luciferase luciferase NN 1214 1222 reporter reporter NN 1223 1227 gene gene NN 1228 1238 activation activation NN 1238 1239 . . . 1240 1248 Targeted target VBN 1249 1259 mutational mutational JJ 1260 1268 analysis analysis NN 1269 1281 demonstrated demonstrate VBD 1282 1286 that that IN 1287 1288 a a DT 1289 1295 tandem tandem JJ 1296 1304 NF-kappa NF-kappa NNP 1305 1310 B/Rel B/Rel NNP 1311 1318 binding binding NN 1319 1324 motif motif NN 1325 1327 is be VBZ 1328 1336 critical critical JJ 1337 1340 for for IN 1341 1344 the the DT 1345 1350 gamma gamma NN 1351 1352 3 3 CD 1353 1356 ECS ecs NN 1357 1371 responsiveness responsiveness NN 1372 1374 to to TO 1375 1379 both both CC 1380 1385 CD40L CD40L NNP 1386 1389 and and CC 1390 1394 IL-4 il-4 NN 1394 1395 , , , 1396 1401 while while IN 1402 1403 a a DT 1404 1418 STAT-6-binding stat-6-binding JJ 1419 1423 site site NN 1424 1426 is be VBZ 1427 1439 additionally additionally RB 1440 1448 required require VBN 1449 1452 for for IN 1453 1457 IL-4 il-4 NN 1458 1470 inducibility inducibility NN 1470 1471 . . . 1472 1487 Electrophoretic electrophoretic JJ 1488 1496 mobility mobility NN 1497 1502 shift shift NN 1503 1509 assays assay NNS 1510 1516 showed show VBD 1517 1521 that that IN 1522 1535 p50/p65/c-Rel p50/p65/c-rel NN 1536 1539 and and CC 1540 1546 STAT-6 STAT-6 NNP 1547 1550 are be VBP 1551 1562 effectively effectively RB 1563 1570 induced induce VBN 1571 1573 by by IN 1574 1579 CD40L CD40L NNP 1580 1583 and and CC 1584 1588 IL-4 il-4 NN 1588 1589 , , , 1590 1602 respectively respectively RB 1602 1603 , , , 1604 1607 and and CC 1608 1612 bind bind VBP 1613 1615 to to TO 1616 1624 specific specific JJ 1625 1628 DNA dna NN 1629 1635 motifs motif NNS 1636 1642 within within IN 1643 1646 the the DT 1647 1650 ECS ecs NN 1650 1651 . . . 1652 1657 These these DT 1658 1667 partially partially RB 1668 1679 overlapping overlap VBG 1680 1685 CD40L cd40l NN 1686 1689 and and CC 1690 1694 IL-4 il-4 NN 1695 1705 responsive responsive JJ 1706 1714 elements element NNS 1715 1718 are be VBP 1719 1731 functionally functionally RB 1732 1743 cooperative cooperative JJ 1744 1746 as as IN 1747 1750 the the DT 1751 1761 disruption disruption NN 1762 1764 of of IN 1765 1768 one one CD 1769 1771 of of IN 1772 1776 them them PRP 1777 1785 prevents prevent VBZ 1786 1797 synergistic synergistic JJ 1798 1806 promoter promoter NN 1807 1817 activation activation NN 1817 1818 . . . 1819 1823 Thus thus RB 1823 1824 , , , 1825 1828 the the DT 1829 1834 gamma gamma NN 1835 1836 3 3 CD 1837 1840 ECS ecs NN 1841 1843 is be VBZ 1844 1846 an an DT 1847 1856 inducible inducible JJ 1857 1865 promoter promoter NN 1866 1876 containing contain VBG 1877 1880 cis cis NN 1881 1889 elements element NNS 1890 1894 that that WDT 1895 1905 critically critically RB 1906 1913 mediate mediate VBP 1914 1919 CD40L CD40L NNP 1920 1923 and and CC 1924 1938 IL-4-triggered il-4-triggered JJ 1939 1954 transcriptional transcriptional JJ 1955 1965 activation activation NN 1966 1968 of of IN 1969 1972 the the DT 1973 1978 human human JJ 1979 1980 C C NNP 1981 1986 gamma gamma NN 1987 1988 3 3 CD 1989 1993 gene gene NN 1993 1994 . . .