Figure 1

Molecular analyses of patients with FIP1L1-PDFGRA rearrangement. A. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of the FIP1L1-PDFGRA fusion gene isolated from bone marrow and peripheral blood of patients with chronic eosinophilic leukaemia at diagnosis. M: 100 bp ladder molecular weight marker (Invitrogen, UK); Lane 1: case 1; Lane 2: case 2; Lane 3: cell line EOL-1 (positive control), Lane 4: negative PCR control (blank). It is noteworthy that both patients, as well as the cell line EOL-1 (positive control), display more than one mRNA isoforms of the fusion gene. B. Sequence variants for each patient with the fusion gene. FIP1L1 sequences are shown in lowercase and in blue, and PDGFRA sequences are shown in uppercase and in black. Exon numbering in FIP1L1 is based on a complementary DNA (cDNA) clone (GenBank accession number NM_030917). The amino acid sequence of the chimeric protein in site of fusion is indicated in green. C. Schematic representation of the FIP1L1-PDGFRA fusion protein. In both cases the breakpoints in PDGFRA are located within the juxtamembrane region, between the two tryptophan (W) residues of the putative WW-domain.