Fig. 1

Alternative splice variants of Survivin encoded by BIRC5 gene. Schematic representation of exons encoding five isoforms of Survivin. Note the breaks in the middle denote introns 1–3. Wild type (WT) is coded by exons 1–4 and is 142 amino acid (aa) long. An additional 69 bp exon between exons 2 and 3 results in Survivin 2B, making it a total of 67 aa in length. Exon 3 deletion leads to a frame shift variant resulting in a 3′ UTR, forming Survivin ΔEx3, 137 aa in length. Survivin 3B is formed by addition of 7 aa at the C-terminal, exon 3B from intron 3, the first 113 aa are conserved from WT Survivin. Variants 2α and 3α have a 3′UTR along with exons 1–2 and are 74 and 78 aa in length respectively