Romeuf et al. BMC Genomics 2010, 11:185 http://www.biomedcentral.com/1471-2164/11/185 Page 9 of 15 Figure 4 Analysis of Dof family from wheat, barley and rice. The accession numbers are indicated for O. sativa and T. aestivum. For Hordeum vulgare details were retrieved from Moreno-Risueno et al. [18]. The unrooted tree was created from an alignment of 50 amino acids of DOF domain sequences from three species using the neighbor-joining method. DOF from different species are shown in different colours (T. aestivum in red, O. sativa in black and H. vulgare in green). The seven groups are indicated and numbered. Scale bar = 0.1 substitution per site. endosperm at different seed developmental stages (Fig- ure 7) by real time PCR. The same primers as above were used that gave efficient amplification and only one PCR-product in dissociation curves. Wheat Dof can be classified into 3 classes according to their expression profiles. Three Dof (TC298479, BE497753 and BE516595) are preferentially expressed during the first step of development when the grain is growing and their expression decreases down to a basal level in the grain-filling and drying-down stages. According to the second expression profile TC332787, TC285930 and CK208471 can be grouped together. These tran- scripts are detected through all developmental stages with three expression peaks: at the ovary stage, at early (150 degree-days) and mid grain-filling. Conversely to the first class, the third class groups Dof that are expressed at a basal level at the beginning of grain development increasing to a maximum midway through grain-filling when starch and storage proteins accumulate. Discussion TFs are important for the regulation of eukaryotic gene expression. In constructing wDBTF the goal was to be comprehensive in collating both the wheat TF sequences and the information about each TF. Instead of relying entirely on computational prediction, we combined automated searches and manual curation to improve the quality of the database. In wDBTF, we define TFs as proteins that show sequence-specific DNA binding and are able to activate and/or repress transcription. The large genome size of wheat (approximately 16,000 Mb) and its polyploid nature make the goal of sequen- cing the wheat genome a difficult one. ESTs are created by partially sequencing randomly isolated gene tran- scripts and they play an important role in gene discov- ery. The availability of more than 1 million T. aestivum ESTs derived from more than 250 libraries has proved an adequate resource for identifying wheat TFs with the added advantage that it can be used to identify tissue- specific expression patterns. In wDBTF, we considered