Identification of ORF RHAMM isoforms from MM plasma cells. (A) Plasma cell ORF RHAMM was amplified, cloned, and colonies screened by PCR with primer set 1 and primer set 4. The amplification products from cloned RHAMM^FL were 613 bp (lane 2) and 666 bp (lane 6), from RHAMM⁻⁴⁸ were 565 bp (lane 3) and 666 bp (lane 7), and from RHAMM⁻¹⁴⁷ were 613 bp (lane 4) and 519 bp (lane 8). Markers (lane 1 and 5) are 700, 600, 500, 400, and 300 bp. (B) A representative clone of each ORF RHAMM isoform was restriction-digested from the PCR TM II vector with EcoRV plusKpn I and sized on a 1% agarose gel. RHAMM^FLis 2.319 kb; RHAMM⁻⁴⁸ is 2.268 kb; and RHAMM⁻¹⁴⁷ is 2.172 kb. Markers are 2.5, 2, 1.5, and 1 kb.