The initiation site is the specific location on DNA where transcription begins. It is typically marked by the +1 nucleotide, where RNA polymerase starts synthesizing RNA.
congrats on reading the definition of initiation site. now let's actually learn it.
The initiation site is situated immediately downstream of the promoter region.
In prokaryotes, the -10 and -35 consensus sequences in the promoter help position RNA polymerase at the initiation site.
The first nucleotide transcribed from the initiation site is complementary to the template strand of DNA.
Mutations at or near the initiation site can affect transcription efficiency and gene expression levels.
The sigma factor in prokaryotes plays a crucial role in recognizing and binding to the promoter to correctly position RNA polymerase at the initiation site.
Review Questions
What role does the sigma factor play in relation to the initiation site?
How do mutations at or near the initiation site affect transcription?
What are the consensus sequences that help position RNA polymerase at the initiation site in prokaryotes?
Related terms
Promoter: A DNA sequence upstream of a gene that provides a binding site for RNA polymerase to initiate transcription.
RNA Polymerase: An enzyme that synthesizes RNA from a DNA template during transcription.
Sigma Factor: A protein that associates with RNA polymerase and facilitates its binding to specific promoters in prokaryotes.