A feedback control element near the transcription start site of the maize Shrunken gene determines promoter activity.

Abstract

The transcriptional activity of the Shrunken (Sh) promoter of Zea mays was monitored in transient expression assays using the neomycin phosphotransferase (NPT) II gene as a reporter in maize suspension protoplasts. Shortly after transfection, expression of this chimeric NPTII gene was negatively affected by high extracellular sucrose concentrations in the protoplast cultivation medium. However, 3‐5 days after transfection an up to 405‐fold increase in NPTII activity was observed. This could be blocked by dichlorobenzonitril (DCB) an inhibitor of cellulose biosynthesis. In the analysis of promoter deletions 20 bp upstream of the Sh transcription start site were sufficient to reproduce the expression profile and the activity of the full promoter. Surprisingly this start sequence does not include the natural TATA‐box.

Sugar Coordinately and Differentially Regulates Growth- and Stress-Related Gene Expression via a Complex Signal Transduction Network and Multiple Control Mechanisms

“…moter region of Sh1 containing the TATCCA element also confers sugar inhibition of downstream reporter gene expression (Maas et al, 1990). These findings suggests that the TATCCA element or its variants could be a common cis-regulatory element responsible for sugar repression.…”

Hexokinase as a sugar sensor in higher plants.

“…Currently, the cis-acting elements and trans-acting factors involved in sugar regulation are not well characterized. Because sugar-mediated gene expression is affected by many diverse signal transduction pathways, distinct regulatory DNA elements and transcription factors are likely to be employed (Liu et al, 1990;Mass et al, 1990;Sheen, 1990Sheen, , 1994Kim et al, 1994;.…”

Metabolite Signals Regulate Gene Expression and Source/Sink Relations in Cereal Seedlings

“…Expression of the maize Suc synthase gene Sus2 is repressed by Suc in protoplasts derived from cultured cells (Maas et al, 1990) and in roots (Koch et al, 1992). The sugar repression of Sus2 gene expression may serve to ensure that the metabolism of incoming Suc does not greatly exceed the rate at which sugar can be incorporated into starch.…”