The TATA-less promoter of VP1, a plant gene controlling seed germination

Vp1 is a seed-specific gene involved in the control of dormancy and germination. We here present the complete sequence of the sorghum vp1 promoter/enhancer region highlighting its main features, especially the lack of canonical TATA and CAAT boxes and the presence of elements responsive to abscisic acid and light. The region closest to the start of transcription is highly homologous to the partial proximal sequence reported for the maize vp1 promoter. This region is interrupted by a 57-nt stretch containing 14 CT microsatellite repeats. We observed a poor overall homology to the promoter from abi3 gene, the Arabidopsis counterpart bearing a similar coding sequence. However, there exists a high degree of homology (89%) between a TATA-rich 103-bp stretch of the sorghum vp1 promoter located about 700 nt upstream of the startpoint and miniature inverted transposable elements (MITEs) interspersed within the sorghum seed-specific kafirin cluster. This sorghum MITE-like element displays considerable homology (68%) to the TATA-less promoter from the sorghum NADP-malate dehydrogenase gene and lesser similarity to the Tourist, Pilgrim and Batuta MITEs previously identified within the promoter from the maize Abp1 (auxin-binding protein) gene.