CAATcontaining

CAATcontaining refers to DNA sequences that include a CAAT box, a common cis-regulatory element in the promoter regions of many eukaryotic genes. The CAAT box is a short motif, often represented by the consensus sequence GGCCAATCT, though natural variants exist. It is typically located upstream of the transcription start site, commonly about 75 to 80 base pairs away, and can occur in one or multiple copies within a promoter.

Promoters that contain CAAT boxes influence transcription initiation by contributing to promoter strength and proper assembly of the transcriptional machinery. They often operate in conjunction with, or in the absence of, a TATA box, helping to regulate transcription across different tissues and developmental stages. The presence of CAAT boxes can modulate responsiveness to cellular signals and environmental cues.

The principal trans-acting factor that binds the CAAT box is the NF-Y complex, a heterotrimer that recognizes the CCAAT motif. Additional transcription factors may interact with CAAT-containing promoters to modulate binding and activity, and chromatin remodelers or histone modifiers are frequently recruited to facilitate access to the DNA and enhance transcription.

Significance and variability: not all promoters contain CAAT boxes, and the presence of a CAAT element does not guarantee high expression in every context. The impact of CAAT-containing promoters varies by cell type, developmental stage, and gene, and mutations within CAAT sites can reduce promoter activity and alter gene regulation.

CAAT-containing promoters are a widely studied example of how short regulatory motifs contribute to the complexity of eukaryotic transcriptional control.