The TATA box and a Myb binding site are essential for anaerobic expressionof a maize GapC4 minimal promoter in tobacco

The maize GapC4 promoter harbours a complex arrangement of cis-sequences in volved in activation of anaerobic gene expression in tobacco, As shown by t ransient expression assays, four copies of a 50 bp anaerobic response eleme nt (ARE) increase anaerobic gene expression compared to the ARE alone. Expr ession strength is similar to a 190 bp fragment that contains most sequence s required for anaerobic expression, including the 50 bp ARE. This supports the notion that redundancy of cis-acting sequences contribute to the anaer obic expression strength of the promoter. Mutation analysis of the 50 bp AR E revealed that cis-regulatory sequences are located within 30 bp at the 5' end of the ARE. Of these 30 bp a putative binding site for a Myb transcrip tion factor is essential for anaerobic induction, The TATA box of the GapC4 promoter is also required for anaerobic gene expression and is bound speci fically by a recombinant TATA box binding protein (TBP) from tobacco. A mod el for anaerobic induction of the GapC4 minimal promoter in tobacco that su mmarizes the presented data is discussed. (C) 2001 Elsevier Science B.V. Al l rights reserved.