0 2 An an DT 3 16 alternatively alternatively RB 17 24 spliced splice VBN 25 32 isoform isoform NN 33 35 of of IN 36 39 the the DT 40 45 Spi-B Spi-B NNP 46 59 transcription transcription NN 60 66 factor factor NN 66 67 . . . 69 74 Spi-B Spi-B NNP 75 77 is be VBZ 78 80 an an DT 81 84 Ets Ets NNP 85 98 transcription transcription NN 99 105 factor factor NN 106 113 related relate VBN 114 116 to to TO 117 120 the the DT 121 132 oncoprotein oncoprotein NN 133 143 Spi-1/PU.1 spi-1/pu.1 NN 144 147 and and CC 148 154 highly highly RB 155 164 expressed express VBN 165 167 in in IN 168 169 B B NNP 170 178 lymphoid lymphoid JJ 179 184 cells cell NNS 184 185 . . . 186 189 The the DT 190 193 Ets Ets NNP 194 202 proteins protein NNS 203 208 share share VBP 209 210 a a DT 211 220 conserved conserve VBN 221 224 Ets ets NN 225 231 domain domain NN 232 236 that that WDT 237 245 mediates mediate VBZ 246 254 specific specific JJ 255 258 DNA dna NN 259 266 binding binding NN 266 267 . . . 268 273 Spi-B Spi-B NNP 274 279 binds bind VBZ 280 283 DNA DNA NNP 284 293 sequences sequence NNS 294 304 containing contain VBG 305 306 a a DT 307 311 core core NN 312 321 5’-GGAA-3 5'-ggaa-3 NN 321 322 ’ ' '' 323 326 and and CC 327 336 activates activate VBZ 337 350 transcription transcription NN 351 358 through through IN 359 363 this this DT 364 369 motif motif NN 369 370 . . . 371 373 Up up IN 374 376 to to TO 377 381 date date NN 381 382 , , , 383 386 the the DT 387 397 biological biological JJ 398 406 function function NN 407 409 of of IN 410 415 Spi-B Spi-B NNP 416 423 remains remain VBZ 424 431 unknown unknown JJ 431 432 . . . 433 437 Here here RB 437 438 , , , 439 441 we we PRP 442 450 describe describe VBP 451 454 the the DT 455 471 characterization characterization NN 472 474 of of IN 475 477 an an DT 478 491 alternatively alternatively RB 492 499 spliced splice VBN 500 507 variant variant NN 508 510 of of IN 511 516 Spi-B Spi-B NNP 516 517 , , , 518 523 named name VBN 524 534 deltaSpi-B deltaspi-b NN 534 535 , , , 536 541 which which WDT 542 545 has have VBZ 546 550 lost lose VBN 551 554 the the DT 555 558 Ets Ets NNP 559 565 domain domain NN 565 566 . . . 567 569 In in IN 570 571 B B NNP 572 580 lymphoid lymphoid JJ 581 586 cells cell NNS 586 587 , , , 588 598 deltaspi-B deltaspi-b NN 599 602 and and CC 603 608 spi-B spi-b NN 609 614 mRNAs mrna NNS 615 619 were be VBD 620 627 present present JJ 628 642 simultaneously simultaneously RB 643 645 in in IN 646 647 a a DT 648 653 ratio ratio NN 654 656 of of IN 657 663 around around IN 664 666 10 10 CD 666 667 % % NN 667 668 . . . 669 679 DeltaSpi-B DeltaSpi-B NNP 680 687 product product NN 688 691 was be VBD 692 695 not not RB 696 700 able able JJ 701 703 to to TO 704 708 bind bind VB 709 712 DNA dna NN 713 716 and and CC 717 720 was be VBD 721 730 recovered recover VBN 731 733 in in IN 734 745 cytoplasmic cytoplasmic JJ 746 754 cellular cellular JJ 755 763 extracts extract NNS 763 764 . . . 765 767 We we PRP 768 773 raise raise VBP 774 777 the the DT 778 788 hypothesis hypothesis NN 789 793 that that IN 794 799 delta delta SYM 800 805 Spi-B spi-b NN 806 811 might might MD 812 818 affect affect VB 819 824 Spi-B spi-b NN 825 833 function function NN 834 836 by by IN 837 847 recruiting recruit VBG 848 855 factors factor NNS 856 864 involved involve VBN 865 867 in in IN 868 873 Spi-B Spi-B NNP 874 882 activity activity NN 882 883 . . .