The TATA box is a short DNA sequence found in the promoter region of many genes in eukaryotic organisms. It typically consists of the nucleotide sequence TATAAA and plays a crucial role in the initiation of transcription, which is the first step in gene expression. The TATA box serves as a binding site for the transcription factor TBP (TATA-binding protein), which helps recruit other proteins necessary for forming the transcription machinery. When the transcription machinery assembles at the TATA box, it unwinds the DNA, allowing RNA polymerase to begin synthesizing messenger RNA (mRNA) from the DNA template. This process is essential for producing proteins that carry out various functions in the cell. The presence of the TATA box is a key feature in the regulation of gene expression.