0 1 A a DT 2 11 mammalian mammalian JJ 12 19 histone histone NN 20 31 deacetylase deacetylase NN 32 39 related relate VBN 40 42 to to TO 43 46 the the DT 47 52 yeast yeast NN 53 68 transcriptional transcriptional JJ 69 78 regulator regulator NN 79 84 Rpd3p Rpd3p NNP 85 86 [ [ ( 86 89 see see VB 90 98 comments comment NNS 98 99 ] ] ) 101 109 Trapoxin Trapoxin NNP 110 112 is be VBZ 113 114 a a DT 115 126 microbially microbially RB 127 134 derived derive VBN 135 152 cyclotetrapeptide cyclotetrapeptide NN 153 157 that that WDT 158 166 inhibits inhibit VBZ 167 174 histone histone NN 175 188 deacetylation deacetylation NN 189 191 in in FW 192 196 vivo vivo FW 197 200 and and CC 201 207 causes cause VBZ 208 217 mammalian mammalian JJ 218 223 cells cell NNS 224 226 to to TO 227 233 arrest arrest VB 234 236 in in IN 237 240 the the DT 241 245 cell cell NN 246 251 cycle cycle NN 251 252 . . . 253 254 A a DT 255 263 trapoxin trapoxin NN 264 272 affinity affinity NN 273 279 matrix matrix NN 280 283 was be VBD 284 288 used use VBN 289 291 to to TO 292 299 isolate isolate VB 300 303 two two CD 304 311 nuclear nuclear JJ 312 320 proteins protein NNS 321 325 that that WDT 326 336 copurified copurifie VBD 337 341 with with IN 342 349 histone histone NN 350 361 deacetylase deacetylase NN 362 370 activity activity NN 370 371 . . . 372 376 Both both DT 377 385 proteins protein NNS 386 390 were be VBD 391 401 identified identify VBN 402 404 by by IN 405 412 peptide peptide NN 413 428 microsequencing microsequencing NN 428 429 , , , 430 433 and and CC 434 435 a a DT 436 449 complementary complementary JJ 450 453 DNA dna NN 454 462 encoding encode VBG 463 466 the the DT 467 474 histone histone NN 475 486 deacetylase deacetylase NN 487 496 catalytic catalytic JJ 497 504 subunit subunit NN 505 506 ( ( ( 506 509 HD1 HD1 NNP 509 510 ) ) ) 511 514 was be VBD 515 521 cloned clone VBN 522 526 from from IN 527 528 a a DT 529 534 human human JJ 535 541 Jurkat Jurkat NNP 542 543 T t NN 544 548 cell cell NN 549 556 library library NN 556 557 . . . 558 560 As as IN 561 564 the the DT 565 574 predicted predict VBN 575 582 protein protein NN 583 585 is be VBZ 586 590 very very RB 591 598 similar similar JJ 599 601 to to TO 602 605 the the DT 606 611 yeast yeast NN 612 627 transcriptional transcriptional JJ 628 637 regulator regulator NN 638 643 Rpd3p Rpd3p NNP 643 644 , , , 645 650 these these DT 651 658 results result NNS 659 666 support support VBP 667 668 a a DT 669 673 role role NN 674 677 for for IN 678 685 histone histone NN 686 697 deacetylase deacetylase NN 698 700 as as IN 701 702 a a DT 703 706 key key JJ 707 716 regulator regulator NN 717 719 of of IN 720 730 eukaryotic eukaryotic JJ 731 744 transcription transcription NN 744 745 . . .