Validating Signal Peptide Function

The function of the predicted signal peptides was verified by the yeast secretion system. To determine the signal peptide secretory activity, the signal peptide of AsCEP50 was cloned into vector pSUC2 using specific primers. The recombinant vector was transformed into yeast strain YTK12. The positive colonies were screened on a CMD−W medium (0.075% tryptophan dropout supplement, 0.67% yeast nitrogen base without amino acids, 2% sucrose, 0.1% glucose, and 2% agar). To test for invertase secretion, successfully transformed yeast strains were grown on YPRA agar (1% yeast extract, 2% peptone, 2% raffinose, 2 mg/mL antimycin A, and 2% agar).