Study On The Structure And Function Of VHA-c Gene Promoter In Arabidopsis Thaliana

Vacuole H+-ATPase is a special membrane-bound transport protein located on the tonoplast and various inner membranes. Under stress conditions, V-ATPase can adapt to various environments by auto-regulation. V-ATPase subunit c is a major component of the membranous V0 sector and forms the proton conductance pathway through hexamer, and sensitive to plant development and environmental changes. There are evidences that V-ATPase subunit c is necessary during resistant responses, but its regulation and expression mechanism are still unclear. Study of V-ATPase subunit c gene is significant to clarify VHA-c genes` function, uncover V-ATPase`s action mechanism during abiotic stresses resistance and develop new useful plant promoters.To understand VHA-c genes expression and regulation mechanism, we compared and analyzed their sequence by bioinformatics approach. Using VHA-c3 as a sample, we cloned different length fragments of VHA-c3 promoter and fused its 3` terminus withβ-glucuronidase (GUS) reporter gene. Using this system, we checked the activity and the regulation of VHA-c3 gene promoter.Our results showed that:1. VHA-c gene promoter contains many cis-elements, including heat shock, drought, wounding, light and plant hormones responsive elements. These peculiar cis-elements are very important for VHA-c gene's differential expression under various environments and its expression levels in various tissues, and they are also one of the important mechanisms for the plant to adapt to stress.2. The essential element for the basal activity of VHA-c3 is located within the -722bp fragments upstream of the translation start codon of VHA-c3.3. Because VHA-c gene promoter can direct GUS gene`s transient and permanent expression, the promoter can be an important regulation element in plant gene engineering.4. The upstream -2234bp to -1496bp fragment VHA-c3 gene's promoter has up-regulated cis-elements, which can offset the down regulation effect that is conducted by it's downstream sequence between -1496bp to -772bp.