abres

ABREs, or Abscisic Acid Responsive Elements, are cis-regulatory DNA motifs found in the promoters of many plant genes. They mediate transcriptional activation in response to the plant hormone abscisic acid (ABA) and are also associated with responses to abiotic stresses such as drought, high salinity, and cold. ABRE-containing promoters are common in diverse plant species, where they help coordinate rapid gene induction under stress conditions.

The ABRE motif typically contains a conserved core sequence, commonly described as ACGTG, with variations in surrounding nucleotides. Because ABREs can occur in different promoter contexts, many promoters host multiple ABREs or ABRE-like sequences, contributing to graded or tissue-specific responses. The motifs are recognized by basic leucine zipper (bZIP) transcription factors, notably the AREB/ABF family in Arabidopsis and their homologs in other plants.

Mechanistically, ABA signaling activates SnRK2 kinases that phosphorylate AREB/ABF factors, enhancing their ability to bind ABREs and recruit the transcriptional machinery. This leads to upregulation of ABA-responsive genes involved in osmotic adjustment, protection against cellular damage, and other protective functions during stress.

In functional terms, ABREs are associated with genes such as late embryogenesis abundant (LEA) proteins and various drought- or salt-responsive genes. Experimental approaches to study ABREs include promoter-reporter assays, electrophoretic mobility shift assays, and chromatin immunoprecipitation, often revealing cooperative interactions between ABREs and other cis-elements to fine-tune expression under varying conditions.