Final answer:
Cis-regulatory sequences are DNA regions that control gene transcription by serving as binding sites for transcription factors. Enhancers and promoter-proximal elements like the CAAT box and the GC box are two examples of such sequences.
Step-by-step explanation:
Cis-regulatory sequences are specific regions of DNA that manage the transcription of the adjacent genes. They play a crucial role in the regulation of gene expression by serving as binding sites for transcription factors. These elements can be located proximal to the gene's promoter or can be distal, influencing the gene's expression from afar.
Two examples of cis-regulatory elements are enhancers and promoter-proximal elements. Enhancers are sequences that, when bound by transcription factors, significantly increase the transcription of a gene. They have the capability to function at a distance from the gene they regulate and can be upstream, downstream, or within the gene. Promoter-proximal elements, on the other hand, are typically located within a few hundred base pairs upstream of the transcription start site and include sequences like the CAAT box and the GC box . These elements also bind transcription factors which help to regulate gene transcription .