Initiator element

[a][1] Similarly to the TATA box, the Inr element facilitates the binding of transcription Factor II D (TFIID).

The initiator element (Inr) is the most common sequence found at the transcription start site (TSS) of eukaryotic genes.

[2] Their research showed that Inr promoter is able to initiate basal transcription in absence of the TATA box.

The TFIID, which is a component of the RNA polymerase II preinitiation complex binds to both the TATA box and Inr.

[7] The Inr element encompasses, simply, the 2-9 bp around the transcription start site (+1) that usually follow a consensus sequence.

Through mutational analysis by Lo and Smale, the "functional" consensus sequence of Inr in humans was inferred to be YYA+1NWYY.

Vo ngoc et al. have characterized the Inr at focused core promoters (those with a single or a narrow cluster of start sites) and found BBCA+1BW.

Though the Inr element is not fully understood it has been recognized as the most frequently occurring sequence at the start site of genes in multiple species.