0 11 Differences difference NNS 12 14 in in IN 15 30 transcriptional transcriptional JJ 31 40 enhancers enhancer NNS 41 43 of of IN 44 49 HIV-1 HIV-1 NNP 50 53 and and CC 54 59 HIV-2 HIV-2 NNP 59 60 . . . 61 69 Response Response NNP 70 72 to to TO 73 74 T t NN 75 79 cell cell NN 80 90 activation activation NN 91 98 signals signal NNS 98 99 . . . 101 102 T t NN 103 107 cell cell NN 108 118 activation activation NN 119 126 results result VBZ 127 129 in in IN 130 134 high high JJ 135 141 levels level NNS 142 144 of of IN 145 148 HIV HIV NNP 149 160 replication replication NN 161 164 and and CC 165 167 is be VBZ 168 175 thought think VBN 176 178 to to TO 179 181 be be VB 182 185 one one CD 186 195 mechanism mechanism NN 196 203 leading lead VBG 204 206 to to TO 207 210 the the DT 211 221 conversion conversion NN 222 226 from from IN 227 233 latent latent JJ 234 236 to to TO 237 243 active active JJ 244 249 viral viral JJ 250 259 infection infection NN 259 260 . . . 261 263 In in IN 264 269 HIV-1 HIV-1 NNP 269 270 , , , 271 274 the the DT 275 284 sequences sequence NNS 285 289 that that WDT 290 297 respond respond VBP 298 300 to to TO 301 306 these these DT 307 316 signaling signaling NN 317 323 events event NNS 324 327 are be VBP 328 333 found find VBN 334 336 in in IN 337 340 the the DT 341 345 long long JJ 346 354 terminal terminal JJ 355 361 repeat repeat NN 362 363 ( ( ( 363 366 LTR LTR NNP 366 367 ) ) ) 368 371 and and CC 372 380 comprise comprise VBP 381 384 the the DT 385 400 transcriptional transcriptional JJ 401 409 enhancer enhancer NN 409 410 , , , 411 416 which which WDT 417 425 contains contain VBZ 426 429 two two CD 430 439 conserved conserve VBN 440 447 binding bind VBG 448 453 sites site NNS 454 457 for for IN 458 461 the the DT 462 469 nuclear nuclear JJ 470 476 factor factor NN 477 482 kappa kappa NN 483 484 B B NNP 485 486 ( ( ( 486 488 NF NF NNP 489 494 kappa kappa NN 495 496 B B NNP 496 497 ) ) ) 497 498 . . . 499 502 The the DT 503 516 corresponding corresponding JJ 517 523 region region NN 524 526 in in IN 527 530 the the DT 531 537 second second JJ 538 542 AIDS AIDS NNP 543 553 retrovirus retrovirus NN 553 554 , , , 555 560 HIV-2 HIV-2 NNP 560 561 , , , 562 570 contains contain VBZ 571 572 a a DT 573 582 conserved conserve VBN 583 586 and and CC 587 588 a a DT 589 598 divergent divergent JJ 599 601 NF NF NNP 602 607 kappa kappa NN 608 609 B B NNP 610 617 binding binding NN 618 622 site site NN 622 623 . . . 624 626 We we PRP 627 638 demonstrate demonstrate VBP 639 643 that that IN 644 647 the the DT 648 653 HIV-1 HIV-1 NNP 654 657 LTR LTR NNP 658 666 responds respond VBZ 667 673 better good JJR 674 678 than than IN 679 682 the the DT 683 688 HIV-2 hiv-2 NN 689 692 LTR ltr NN 693 695 to to TO 696 697 T t NN 698 702 cell cell NN 703 713 activation activation NN 714 721 signals signal NNS 721 722 . . . 723 728 These these DT 729 740 qualitative qualitative JJ 741 752 differences difference NNS 753 755 in in IN 756 759 the the DT 760 768 response response NN 769 771 to to TO 772 773 T t NN 774 778 cell cell NN 779 789 activation activation NN 790 793 are be VBP 794 804 reproduced reproduce VBN 805 808 not not RB 809 813 only only RB 814 818 when when WRB 819 824 HIV-1 HIV-1 NNP 825 827 or or CC 828 833 HIV-2 hiv-2 NN 834 843 enhancers enhancer NNS 844 847 are be VBP 848 854 placed place VBN 855 863 upstream upstream RB 864 866 of of IN 867 868 a a DT 869 881 heterologous heterologous JJ 882 890 promoter promoter NN 891 894 but but CC 895 899 also also RB 900 904 when when WRB 905 910 these these DT 911 920 enhancers enhancer NNS 921 924 are be VBP 925 933 switched switch VBN 934 941 between between IN 942 947 their their PRP$ 948 958 respective respective JJ 959 962 LTR ltr NN 962 963 . . . 964 966 In in IN 967 982 electrophoretic electrophoretic JJ 983 991 mobility mobility NN 992 997 shift shift NN 998 1004 assays assay NNS 1004 1005 , , , 1006 1008 NF NF NNP 1009 1014 kappa kappa NN 1015 1016 B B NNP 1017 1022 binds bind VBZ 1023 1025 to to TO 1026 1030 both both DT 1031 1040 conserved conserve VBN 1041 1046 sites site NNS 1047 1049 in in IN 1050 1053 the the DT 1054 1059 HIV-1 HIV-1 NNP 1060 1075 transcriptional transcriptional JJ 1076 1084 enhancer enhancer NN 1085 1088 and and CC 1089 1093 only only RB 1094 1096 to to TO 1097 1100 the the DT 1101 1107 single single JJ 1108 1117 conserved conserve VBN 1118 1122 site site NN 1123 1125 in in IN 1126 1129 the the DT 1130 1135 HIV-2 hiv-2 NN 1136 1151 transcriptional transcriptional JJ 1152 1160 enhancer enhancer NN 1160 1161 . . . 1162 1169 Instead instead RB 1170 1172 of of IN 1173 1175 NF NF NNP 1176 1181 kappa kappa NN 1182 1183 B B NNP 1183 1184 , , , 1185 1188 the the DT 1189 1198 activator activator NN 1199 1206 protein protein NN 1207 1208 3 3 CD 1209 1214 binds bind VBZ 1215 1217 to to TO 1218 1221 the the DT 1222 1231 divergent divergent JJ 1232 1236 site site NN 1237 1239 in in IN 1240 1245 HIV-2 hiv-2 NN 1245 1246 . . . 1247 1249 In in IN 1250 1260 conclusion conclusion NN 1260 1261 , , , 1262 1267 HIV-1 HIV-1 NNP 1268 1271 and and CC 1272 1277 HIV-2 HIV-2 NNP 1278 1281 are be VBP 1282 1296 differentially differentially RB 1297 1306 regulated regulate VBN 1307 1309 by by IN 1310 1311 T t NN 1312 1316 cell cell NN 1317 1327 activation activation NN 1328 1335 signals signal NNS 1335 1336 , , , 1337 1340 and and CC 1341 1345 this this DT 1346 1356 difference difference NN 1357 1360 may may MD 1361 1368 account account VB 1369 1372 for for IN 1373 1376 the the DT 1377 1383 longer long JJR 1384 1390 period period NN 1391 1393 of of IN 1394 1399 viral viral JJ 1400 1407 latency latency NN 1408 1416 observed observe VBN 1417 1421 with with IN 1422 1427 HIV-2 hiv-2 NN 1428 1432 than than IN 1433 1437 with with IN 1438 1443 HIV-1 HIV-1 NNP 1444 1453 infection infection NN 1453 1454 . . .