cis Elements and Transcription Factors Regulating Gene Promoters in Response to Environmental Stress

Abstract

Plants alter their patterns of gene expression in response to environmental stress, and a reprogramming of plant metabolism upon abiotic/biotic stimuli involves changes in plant gene expression. In other words, the expression of many genes involved in primary and secondary metabolism is induced by various ecotoxicological stressors. Similarly, pathogenesis-related genes are induced by a variety of stressors. These changes are the result of a modification in the rate of transcription for specific genes. An eukaroytic gene is divided into several sections. There is a transcribed region, existing of the coding sequence, a 3′ and 5′ untranslated region of mRNA, a promoter region and an upstream regulatory region (Ferl and Paul 2000). The promoter of a single gene can be activated by different external stimuli, but promoters of different genes can also be activated by the same stimuli. Thus, the organization of different promoter sections and the architecture of promoters contribute to the complex gene regulation upon external stressors. The promoter contains several elements important for the transcription of the protein coding DNA sequence. These regulatory elements are called cis elements. In general these elements are between 4–20 bp long. Not only their sequence is important for controlling transcription, but also their position relative to the transcription start and relative to other cis elements. The basic cis elements of eukaryotic genes are the TATA and CAAT or CCAAT boxes.