5TGACGTCA3

5TGACGTCA3 denotes the 5' to 3' orientation of the DNA sequence TGACGTCA, an eight-nucleotide palindromic motif that is the canonical cAMP response element (CRE). The palindromic property means its reverse complement is the same sequence, allowing recognition on either DNA strand.

Biological role: CREs bind CREB (cAMP response element-binding) proteins and related transcription factors. When intracellular cAMP rises, CREB is phosphorylated and recruits coactivators such as CBP/p300, promoting transcription of target genes. The CRE sequence thus links extracellular signals to transcriptional responses.

Genomic distribution and regulation: CREs are found in promoters and distal enhancers of many genes, particularly those involved in metabolism, neuronal function, and plasticity. The number and context of CREs, as well as interactions with nearby motifs, influence transcriptional output. Some CREs tolerate minor sequence variations, while the exact TGACGTCA motif yields optimal CREB binding.

Research and practical use: In molecular biology, the TGACGTCA CRE is used in reporter constructs to study cAMP signaling and transcriptional regulation. Epigenetic modification at CpG sites within CREs can affect binding affinity and gene expression.