Oligomerisation of the 57 bp sequence and 3' deletions of the AtMYB60 minimal promoter. A, Schematic diagrams of the constructs. In the 4x::GUS construct the fragment of 57 bp between -262 and -205 in tandem array of four copies was fused to the minimal promoter CaMV 35S (min 35S in the scheme, portion between -46 and +1) upstream of the GUS reporter gene. In the constructs -137-3'::GUS and -148-3'::GUS, 3' deleted versions of the AtMYB60 minimal promoter were fused to the same portion of the CaMV 35S. (B) Relative expression level of the GUS reporter gene in the different transgenic lines harbouring the constructs. Two lines for each construct were analysed by Real Time RT-PCR. The transcript amount in the line -1307 A was arbitrarily set to 1 (black column) and used to normalize the relative expression levels in each line. The ACTIN2 gene was used as a control. The symbols are the same described in Figure 2. The dotted lines indicate the regions deleted in AtMYB60 minimal promoter sequences.