Figure 1

Functional analysis of the WSSV ie1 promoter through deletion and mutation. (A) The 388 bp sequence of the WSSV ie1 promoter is shown. The numbers are relative to the transcription start site (+1). The specific protein binding sites such as Sp1 and the TATA box are underlined. The transcription start site is shown in italics and bold. (B) The schematic depicts the features of the WSSV ie1 promoter that is positioned between the putative translational start site and its 388-bp upstream sequence. A series of truncated promoter fragments were constructed in front of the luciferase gene in a promoter-less vector phRG-B. For the 5' end and the 3' ends, each deletion and mutation of the promoter is depicted and named as shown in the figure. The putative Sp1-binding site and TATA box were mutated [p(-55/+53Δ)and p(-35/+53Δ)] using PCR with a mutated primer. (C) Functional mapping of the cis-elements within the 80-bp sequence (from -135 to -55 bp). The region spanning 80 bp of the promoter was progressively deleted from its 5'-end.