tokens: As an important control for the above targeting experiments , we showed that plasmids L1 - L6 ( Fig . 5A ) as well as L7 and L8 ( Fig . 5B ) bearing LexA - fusion genes had no effect on URA3 silencing in strain 1 ( Fig . 1 ) in which there was no binding site for LexA present between HML - I and URA3 ( data not shown ) .