Fig. 4

Cytogenetic, FISH, and PCR analyses of the AML patient. a G-banded karyotype showing trisomy 6, der(8), der(11), and der(19) of the t(8;19;11)(q24;p13;q23) together with the corresponding normal chromosome homologs; breakpoint positions are indicated by arrows. b FISH using an MLL breakapart probe showed rearrangement of MLL. The 3´-end part of the MLL gene (red probe) has moved to the q arm of the der(8), while the 5´-end part of the gene (green probe) remains on 11q23 of the der(11). c The initial RT-PCR amplifications for the detection of a possible MLL-ELL fusion transcript. Lane 1, nested PCR with the forward primers located in exon 7 of MLL and reverse primers located in exon 4 of ELL (MLL-3947F1/ELL-415R) failed to amplify any cDNA fragments. Lane 2, amplification of a cDNA fragment of the ABL1 gene using the primers ABL1-91F1 and AsBL1-404R1 suggested that the synthesized cDNA was of good quality. d RT-PCR using a new reverse primer located in exon 8 of ELL (primer ELL-1044R1) and a forward primer located in exon 7 of MLL (primer MLL-3878F) amplified a cDNA fragment. M, 1 Kb DNA ladder. e Partial sequence chromatogram of the amplified fragment using the primers MLL-3878F and ELL-1044R1 showing the junction of the MLL-ELL chimeric transcript