RT-PCR products of 3′-ends of the coding region of Pax5 transcripts differ between malignant and normal B cell–enriched populations.

Shown are RT-PCR products that were generated with a pair of primers designed to amplify a 585 bp product in the 3′-end of the coding region of Pax5. All templates were mRNA derived from B cell–enriched populations. P indicates MM patient; H, healthy donor. (Lane M) A 100-bp ladder (Boehringer Mannheim). Products of 300 bp or less in this RT-PCR were not readily identifiable. (Lane 1) A no-template control. (Lane 2) An unidentified product for P8. (Lane 3) The uppermost product observed for P3 (arrow) is a doublet composed of a 498-bp product and a 483-bp product that were identified as Pax5 isoforms missing exons 9 and 8, respectively. A product at 396 bp is an isoform missing Pax5 exons 7 and 8 in tandem. (Lanes 4 and 5) Products identified for H3 and H1 include the expected product of 585 bp, a product at 396 bp that is missing exons 7 and 8, and a product at 500 bp that is a mixed hybrid of one strand of the 585-bp and one strand of the 396-bp product.