We describe a series of transcriptional activators generated by adding amin
o acids (eight in one case, six in another) to fragments of the yeast Sacch
aromyces cerevisiae activator Gal4 that dimerize and bind DNA. One of the n
avel activating regions identified by this procedure is unusual, compared w
ith previously characterized yeast activating regions, in the following way
s: it works more strongly than does Gal4's natural activating region as ass
ayed in yeast; it is devoid of acidic residues; and several lines of eviden
ce suggest that it sees targets in the yeast transcriptional machinery at l
east partially distinct from those seen by Gal4's activating region.