0 7 Cloning Cloning NNP 8 11 and and CC 12 28 characterization characterization NN 29 31 of of IN 32 35 the the DT 36 40 beta beta NN 41 48 subunit subunit NN 49 51 of of IN 52 57 human human JJ 58 66 proximal proximal JJ 67 75 sequence sequence NN 76 91 element-binding element-binding JJ 92 105 transcription transcription NN 106 112 factor factor NN 113 116 and and CC 117 120 its its PRP$ 121 132 involvement involvement NN 133 135 in in IN 136 149 transcription transcription NN 150 152 of of IN 153 158 small small JJ 159 166 nuclear nuclear JJ 167 170 RNA RNA NNP 171 176 genes gene NNS 177 179 by by IN 180 183 RNA RNA NNP 184 195 polymerases polymeras NNS 196 198 II ii CD 199 202 and and CC 203 206 III iii CD 206 207 . . . 209 212 The the DT 213 221 proximal proximal JJ 222 230 sequence sequence NN 231 238 element element NN 239 240 ( ( ( 240 252 PSE)-binding pse)-binding JJ 253 266 transcription transcription NN 267 273 factor factor NN 274 275 ( ( ( 275 278 PTF PTF NNP 278 279 ) ) ) 279 280 , , , 281 286 which which WDT 287 292 binds bind VBZ 293 296 the the DT 297 300 PSE PSE NNP 301 303 of of IN 304 308 both both CC 309 312 RNA RNA NNP 313 323 polymerase polymerase NN 324 327 II- II- NNP 328 331 and and CC 332 335 RNA RNA NNP 336 346 polymerase polymerase NN 347 362 III-transcribed iii-transcribed JJ 363 372 mammalian mammalian JJ 373 378 small small JJ 379 386 nuclear nuclear JJ 387 390 RNA RNA NNP 391 392 ( ( ( 392 397 snRNA snRNA NNP 397 398 ) ) ) 399 404 genes gene NNS 404 405 , , , 406 408 is be VBZ 409 418 essential essential JJ 419 422 for for IN 423 428 their their PRP$ 429 442 transcription transcription NN 442 443 . . . 444 446 We we PRP 447 457 previously previously RB 458 466 reported report VBD 467 470 the the DT 471 483 purification purification NN 484 486 of of IN 487 492 human human JJ 493 496 PTF PTF NNP 496 497 , , , 498 499 a a DT 500 507 complex complex NN 508 510 of of IN 511 515 four four CD 516 524 subunits subunit NNS 524 525 , , , 526 529 and and CC 530 533 the the DT 534 543 molecular molecular JJ 544 551 cloning cloning NN 552 555 and and CC 556 572 characterization characterization NN 573 575 of of IN 576 579 PTF PTF NNP 580 585 gamma gamma NN 586 589 and and CC 590 595 delta delta NN 596 604 subunits subunit NNS 604 605 . . . 606 610 Here here RB 611 613 we we PRP 614 622 describe describe VBP 623 626 the the DT 627 636 isolation isolation NN 637 640 and and CC 641 651 expression expression NN 652 654 of of IN 655 656 a a DT 657 661 cDNA cdna NN 662 670 encoding encode VBG 671 674 PTF ptf NN 675 679 beta beta NN 679 680 , , , 681 683 as as RB 684 688 well well RB 689 691 as as IN 692 702 functional functional JJ 703 710 studies study NNS 711 716 using use VBG 717 725 anti-PTF anti-ptf JJ 726 730 beta beta NN 731 741 antibodies antibody NNS 741 742 . . . 743 749 Native native JJ 750 753 PTF ptf NN 754 758 beta beta NN 758 759 , , , 760 762 in in IN 763 769 either either DT 770 777 protein protein NN 778 787 fractions fraction NNS 788 790 or or CC 791 792 a a DT 793 806 PTF-Oct-1-DNA PTF-Oct-1-DNA NNP 807 814 complex complex NN 814 815 , , , 816 819 can can MD 820 822 be be VB 823 833 recognized recognize VBN 834 836 by by IN 837 847 polyclonal polyclonal JJ 848 858 antibodies antibody NNS 859 865 raised raise VBN 866 873 against against IN 874 885 recombinant recombinant JJ 886 889 PTF PTF NNP 890 894 beta beta NN 894 895 . . . 896 911 Immunodepletion immunodepletion NN 912 919 studies study NNS 920 924 show show VBP 925 929 that that IN 930 933 PTF PTF NNP 934 938 beta beta NN 939 941 is be VBZ 942 950 required require VBN 951 954 for for IN 955 968 transcription transcription NN 969 971 of of IN 972 976 both both DT 977 984 classes class NNS 985 987 of of IN 988 993 snRNA snrna NN 994 999 genes gene NNS 1000 1002 in in FW 1003 1008 vitro vitro FW 1008 1009 . . . 1010 1012 In in IN 1013 1021 addition addition NN 1021 1022 , , , 1023 1042 immunoprecipitation immunoprecipitation NN 1043 1051 analyses analysis NNS 1052 1063 demonstrate demonstrate VBP 1064 1068 that that IN 1069 1080 substantial substantial JJ 1081 1084 and and CC 1085 1092 similar similar JJ 1093 1098 molar molar JJ 1099 1106 amounts amount NNS 1107 1109 of of IN 1110 1122 TATA-binding tata-binding JJ 1123 1130 protein protein NN 1131 1132 ( ( ( 1132 1135 TBP TBP NNP 1135 1136 ) ) ) 1137 1140 and and CC 1141 1149 TFIIIB90 TFIIIB90 NNP 1150 1153 can can MD 1154 1160 weakly weakly RB 1161 1170 associate associate VB 1171 1175 with with IN 1176 1179 PTF PTF NNP 1180 1182 at at IN 1183 1186 low low JJ 1187 1191 salt salt NN 1192 1202 conditions condition NNS 1202 1203 , , , 1204 1207 but but CC 1208 1212 this this DT 1213 1224 association association NN 1225 1227 is be VBZ 1228 1240 dramatically dramatically RB 1241 1248 reduced reduce VBN 1249 1251 at at IN 1252 1256 high high JJ 1257 1261 salt salt NN 1262 1276 concentrations concentration NNS 1276 1277 . . . 1278 1283 Along along IN 1284 1288 with with IN 1289 1292 our our PRP$ 1293 1301 previous previous JJ 1302 1315 demonstration demonstration NN 1316 1318 of of IN 1319 1323 both both DT 1324 1332 physical physical JJ 1333 1345 interactions interaction NNS 1346 1353 between between IN 1354 1357 PTF PTF NNP 1358 1367 gamma/PTF gamma/PTF NNP 1368 1373 delta delta NN 1374 1377 and and CC 1378 1381 TBP TBP NNP 1382 1385 and and CC 1386 1389 the the DT 1390 1401 involvement involvement NN 1402 1404 of of IN 1405 1413 TFIIIB90 tfiiib90 NN 1414 1416 in in IN 1417 1420 the the DT 1421 1434 transcription transcription NN 1435 1437 of of IN 1438 1443 class class NN 1444 1447 III iii CD 1448 1453 snRNA snRNA NNP 1454 1459 genes gene NNS 1459 1460 , , , 1461 1466 these these DT 1467 1474 results result NNS 1475 1478 are be VBP 1479 1489 consistent consistent JJ 1490 1494 with with IN 1495 1498 the the DT 1499 1505 notion notion NN 1506 1510 that that IN 1511 1512 a a DT 1513 1527 TBP-containing tbp-containing JJ 1528 1535 complex complex NN 1536 1543 related relate VBN 1544 1546 to to TO 1547 1553 TFIIIB TFIIIB NNP 1554 1556 is be VBZ 1557 1565 required require VBN 1566 1569 for for IN 1570 1573 the the DT 1574 1587 transcription transcription NN 1588 1590 of of IN 1591 1596 class class NN 1597 1600 III iii CD 1601 1606 snRNA snRNA NNP 1607 1612 genes gene NNS 1612 1613 , , , 1614 1617 and and CC 1618 1622 acts act VBZ 1623 1630 through through IN 1631 1635 weak weak JJ 1636 1647 interaction interaction NN 1648 1652 with with IN 1653 1656 the the DT 1657 1669 four-subunit four-subunit JJ 1670 1673 PTF ptf NN 1673 1674 . . .