Gateway Entry vector design. Schematic drawing of the cloning strategy to generate modified Entry vectors. pENT-STOP vector was constructed starting from pENTR1A (Invitrogen) by introducing, in place of the ccd B toxicity gene, a short cloning site region and a STOP codon immediately after the Not I site. The six different tags were cloned in both the 3' orientation for C-terminal tagging (pEc-TAG) and 5' orientation for N-terminal tagging (pEn-TAG). All these vectors have the same cloning sites, Bam H I and Not I, to allow insertion of the gene of interest without stop codon both for N-terminal and C-terminal tagging because a stop codon is already present within the vectors.