Identification of an RBM6-RBM5 chimeric transcript by nested RT-PCR. Ai. Agarose gel of the nested RT-PCR result from MDA-MB-231 mRNA, using outer primers RBM6E8F and RBM5E7R and inner primers RBM6E17F and RBM5E4R, showing the ~550 bp amplicon in lane 2. Lane 1: DNA ladder (1 kb, Invitrogen). Aii. Schematic of the amplified 550 bp fragment, showing the splicing out of RBM6 exons 20 and 21, and RBM5 exon 1. Blue boxes indicate exons of RBM6, orange boxes indicate exons of RBM5, dotted lines delineate site of intragenic splicing. B. Agarose gel of the nested RT-PCR results for full-length RBM6-RBM5 chimeric transcripts, using outer primers RBM6Fb and RBM5E7R and inner primers RBM6Fc and RBM5E5R. The three chimeric transcripts are from different experiments. Chimeric transcripts 1 and 3 were amplified from Jurkat cells, whereas chimeric transcript 2 was amplified from skeletal muscle tumour. M1: 1 kb DNA ladder (Invitrogen). M2: 1 kb DNA ladder (New England Biolabs). Arrow identifies the faint amplicon observed for chimeric transcript 3. C. Schematic detailing the splicing patterns associated with the three chimeric transcripts. Numbered boxes represent exons, dotted lines represent alternative splice sites. Arrows: delineate putative translation start codons of longest ORFs. Stop signs: represent putative translation stop codons of the longest ORFs. The triangle in chimeric transcript 2 indicates the site of the 17 nucleotide insertion (represented by the red line) from RBM6 intron 10. Not drawn to scale.