0 16 Characterization characterization NN 17 19 of of IN 20 23 the the DT 24 29 human human JJ 30 46 immunodeficiency immunodeficiency NN 47 52 virus virus NN 53 57 type type NN 58 59 1 1 CD 60 76 enhancer-binding enhancer-binding JJ 77 85 proteins protein NNS 86 90 from from IN 91 94 the the DT 95 100 human human JJ 101 107 T-cell t-cell NN 108 112 line line NN 113 119 Jurkat Jurkat NNP 119 120 . . . 122 125 The the DT 126 139 transcription transcription NN 140 142 of of IN 143 146 the the DT 147 152 human human JJ 153 169 immunodeficiency immunodeficiency NN 170 175 virus virus NN 176 180 type type NN 181 182 1 1 CD 183 184 ( ( ( 184 189 HIV-1 HIV-1 NNP 189 190 ) ) ) 191 193 is be VBZ 194 199 under under IN 200 203 the the DT 204 211 control control NN 212 214 of of IN 215 223 cellular cellular JJ 224 232 proteins protein NNS 233 237 that that WDT 238 242 bind bind VBP 243 245 to to TO 246 249 the the DT 250 255 viral viral JJ 256 260 long long JJ 261 269 terminal terminal JJ 270 276 repeat repeat NN 277 278 ( ( ( 278 281 LTR LTR NNP 281 282 ) ) ) 282 283 . . . 284 289 Among among IN 290 293 the the DT 294 309 protein-binding protein-binding JJ 310 317 regions region NNS 318 320 of of IN 321 324 the the DT 325 330 HIV-1 HIV-1 NNP 331 334 LTR LTR NNP 335 337 is be VBZ 338 341 the the DT 342 364 transcription-enhancer transcription-enhancer JJ 365 371 region region NN 371 372 . . . 373 375 We we PRP 376 380 show show VBP 381 385 that that IN 386 388 at at IN 389 394 least least JJS 395 398 one one CD 399 408 inducible inducible JJ 408 409 , , , 410 412 C1 C1 NNP 412 413 , , , 414 417 and and CC 418 421 one one CD 422 434 constitutive constitutive JJ 434 435 , , , 436 438 C2 C2 NNP 438 439 , , , 440 447 protein protein NN 448 451 can can MD 452 456 bind bind VB 457 459 to to TO 460 463 the the DT 464 467 HIV HIV NNP 468 476 enhancer enhancer NN 477 479 in in IN 480 486 Jurkat Jurkat NNP 487 492 cells cell NNS 492 493 . . . 494 497 The the DT 498 501 two two CD 502 510 proteins protein NNS 511 517 differ differ VBP 518 520 in in IN 521 526 their their PRP$ 527 534 surface surface NN 535 541 charge charge NN 541 542 , , , 543 548 since since IN 549 553 they they PRP 554 557 are be VBP 558 567 separable separable JJ 568 570 by by IN 571 585 anion-exchange anion-exchange NN 586 600 chromatography chromatography NN 600 601 . . . 602 610 Bivalent bivalent JJ 611 618 cations cation NNS 619 623 such such JJ 624 626 as as IN 627 631 Mg2+ Mg2+ NNP 632 635 and and CC 636 640 Zn2+ Zn2+ NNP 641 655 differentially differentially RB 656 662 affect affect VB 663 668 their their PRP$ 669 676 binding binding NN 677 679 to to TO 680 696 oligonucleotides oligonucleotide NNS 697 702 which which WDT 703 710 contain contain VBP 711 714 the the DT 715 727 HIV-enhancer hiv-enhancer NN 728 734 domain domain NN 734 735 . . . 736 740 Both both CC 741 743 C1 c1 NN 744 747 and and CC 748 750 C2 c2 NN 751 759 proteins protein NNS 760 764 also also RB 765 769 bind bind VBP 770 772 to to TO 773 774 a a DT 775 782 similar similar JJ 783 791 sequence sequence NN 792 797 found find VBN 798 800 in in IN 801 804 the the DT 805 827 interleukin-2-receptor interleukin-2-receptor NN 828 841 alpha-subunit alpha-subunit NN 842 850 enhancer enhancer NN 850 851 . . . 852 855 The the DT 856 865 inducible inducible JJ 866 868 C1 c1 NN 869 876 protein protein NN 877 880 was be VBD 881 890 partially partially RB 891 899 purified purify VBN 900 902 by by IN 903 908 three three CD 909 924 chromatographic chromatographic JJ 925 930 steps step NNS 931 934 and and CC 935 948 characterized characterize VBN 949 951 by by IN 952 956 u.v. u.v. NN 957 970 cross-linking cross-linking NN 971 973 as as IN 974 975 a a DT 976 978 47 47 CD 979 982 kDa kda NN 983 990 protein protein NN 990 991 . . .