Comparison of the two shRNA construction methods.

<p>(A) The shRNA clone method based on one long oligonucleotide (MO). The oligo underlined was synthesized and annealed to its self to form double strands. (B) The shRNA clone method based on two short oligonucleotides (MT). Two short oligonucleotides (underlined) were synthesized and the 5'-end of the oligo containing the loop sequence (TTCTAGAA) phosphorylated by the T4 polynucleotide kinase in the presence of ATP. Then, the two short oligonucleotides were annealed to form double strands. (C) The shRNA cloning efficiency of the two methods was compared. The vector pshOK-basic was digested with <i>Sap</i> I and ligated with the annealed double strand oligos as described above. The “control” group represents the linearized pshOK-basic ligated in the absence of oligos. Means and standard deviations were generated from 3 independent experiments.