SeeDev-binary@ldeleger:SeeDev-binary-19594710-5 JSONTXT

The AW-box in the 5′-UTR functions as a cis-element for expression during seed development One or two AW-box sequences were identified within the 1000-bp proximal sequence upstream of the ATG codon of 19 genes for FA synthesis in plastids (Figure 7). AW-boxes are also present in the proximal upstream regions of GPT2 (Niewiadomski et al., 2005), PPT/CUE1 (Knappe et al., 2003), and BIO2 for biotin synthesis (Arnal et al., 2006). Direct targets of WRI1 may also include genes with sequences that are slightly different from the AW-box and genes with AW-boxes in other locations. Similar to genes encoding subunits of photosynthetic apparatus in plastids (Nakamura et al., 2002), many genes involved in FA synthesis in plastids have TATA-less promoters. Many AW-boxes are located near TSS and in the 5′-UTR of genes involved in FA synthesis, irrespective of the presence of the TATA-element (Figure 7). Mutational analysis has indicated that both site 1 and site 2 AW-boxes of Pl-Pkβ1 are functional as cis-elements for activation by WRI1 in protoplasts and for expression during seed development (Figure 6c,d). Both of the two AW-boxes in the upstream region of BCCP2 were also involved in transactivation by WRI1. It has been reported that the transcriptional activator AtPurα of Arabidopsis binds to the telo-box that is present in the 5′-UTR or near the TSS of many ribosomal protein genes, and it interacts with the TCP family transcription factor that binds to site II sequences located upstream of the telo-box (Trémousaygue et al., 2003).