Figure 4. Deletion analysis of upstream cis-acting elements of map4 ⁺.

(A) Putative promoter sequence of the map4 ⁺ gene. Two possible TR-box elements (blue and green) and a TATA-like box (red) are italicized and underlined. The transcription start site was identified by sequencing of several cDNA clones (Nakamura et al, unpublished). (B) β-galactosidase assay of the promoter intensity of a map4 promoter-lacZ fusion gene with different deletions of the promoter sequence of the map4 gene. A heterothallic h ⁺ strain (FS85) was transformed with the multicopy plasmid pTA(map4^PRO-lacZ) or the deletion constructs. Cells of the transformants were precultured in SSL+N without leucine and then transferred to SSL−N medium containing 200 nM of synthetic M-factor (filled bar) or SSL−N alone (open bar). After 6 hr, β-gal activity was assayed.