Knockdown of CCDC26 with shRNAs. A. Sequences of shRNAs used in this work. The stems formed in hairpin structures are indicated with bold type. The heads of hairpin structures are indicated by underlined sequence. B. First screen of CCDC26 suppression with shRNA vectors. Clones 22B11, 32H8, 3–4 and 3D1 were used in further investigations (bold type). Clone 32E3 was omitted after a second screening. Targets of the shRNAs are mapped on exon structures (1-2-3-4 and 1a-3-4) of the CCDC26 mRNA variants (see Figure 1B). C. Expression of CCDC26 exon 3–4 in four clones, 3–4, 22B11, 3D1 and 32H8, selected after the second screening. All values were normalized to the expression of CCDC26 in K562 cells.