Are right TALEN and left TALEN harbored in separate expression vector plasmids and delivered together in protoplast for mutational studies? Or are both of these TALEN pairs designed to be expressed from a single expression vector?
Both the ways are possible. Two TALENs (right and left) are required to make double stranded break at a certain site in DNA. These two TALENs can be one plasmid or in two separate plasmids. Although, in most of the vectors, two TALENs are in separate plasmids.