Figure 5.

Scheme of the HYDA1 upstream region (top) and of chimeric constructs of various fragments of the HYDA1 promoter fused to the luciferase-encoding CRLUC reporter gene analyzed in this study (bottom). A schematic of the HYDA1 upstream region from position −1,018 to +159 is shown at the top. Positions and 6-nucleotide sequences of GTAC sites including the 3′ and 5′ adjacent nucleotides are indicated. M1 and M2 refer to tentatively assigned motifs which appeared in the upstream regions of the C. reinhardtii and C. moewusii HYDA2 genes in the exact same sequence (see text for details). An arrow labeled with HYDA1 indicates the translation start codon ATG. Chimeric constructs are depicted below. Names of the constructs are indicated on the right. Length of the HYDA1 promoter fragments are indicated by numbers on the left, which refer to the position relative to the transcription start site (TS). Gray boxes indicate the presence of the wild-type sequences of the GTAC sites and the sequences termed M1 and M2. Black boxes show that the respective sequence has been mutated. GTAC sites were exchanged by GGCC (distal) and TGAC (proximal), respectively. M1 (AAGCTCGC) was changed to CTCATCGC, and M2 (CGCAGGCAC) was altered to ACAAGGCAC.