Cis-regulatory elements (CREs) are spans of non-coding DNA that bind transcription factors and other regulatory molecules ultimately regulating gene expression. Gene promoters and enhancers are two types of CREs.
Eukaryotic genes usually are associated with a single promoter that is located external to the gene but near the transcription start site. Enhancers can be located upstream, downstream or within an intron.
Genes generally contain both exons and introns. Because the exons are the sequences that are used for producing the mRNA that will be translated into protein, exons begin and end the gene sequence. Intron sequences are removed from transcribed RNA.
Which of the following diagrams illustrates a correct illustration of the relationships between CREs and the gene?
Select ALL that apply.