FIGURE 3 (a) The reporter gene construct used for deletion analysis of Gal4p. Only constructs with functional Gal4p will bind UASGAL and drive expression of the reporter gene (lacZ). (b) Deletion analysis of Gal4p. Two activities were measured: in vitro DNA binding (indicated by + or − in the first column on the right) and in vivo transcriptional activation of the reporter gene construct (second column). (c) In this model of the Gal4 protein, derived from the deletion analysis, Gal4p has separable DNA-binding and transcription-activation domains joined by a flexible linker. (d) The DNA-binding domain, expressed alone, will bind DNA but will not activate transcription.