The DNA sequences shown below are from the promoter regions of six bacterial genes. In each case, the last nucleotide in the sequence (highlighted in blue) is the  nucleotide that initiates transcription. Determine the consensus sequence for the Pribnow box from these sequences. <>

Key Concepts

Pribnow Box

The Pribnow box, also known as the -10 region, is a conserved sequence found in bacterial promoters, typically located about 10 nucleotides upstream of the transcription start site. It is crucial for the binding of RNA polymerase and the initiation of transcription. The consensus sequence for the Pribnow box is usually represented as 'TATAAT', which is recognized by the sigma factor of RNA polymerase.

Consensus Sequence

A consensus sequence is a sequence of DNA that represents the most common nucleotides found at each position in a set of related sequences. It is derived from multiple sequences and highlights the nucleotides that are most frequently observed, providing insight into the functional elements of the DNA. In the context of the Pribnow box, the consensus sequence helps identify the key nucleotides necessary for effective transcription initiation.

Transcription Initiation

Transcription initiation is the process by which RNA polymerase binds to a promoter region of DNA and begins synthesizing RNA. This process is critical for gene expression and is regulated by various factors, including the presence of specific sequences like the Pribnow box. Understanding transcription initiation is essential for analyzing how genes are turned on or off in response to cellular signals.