Question

Which gene or genes on the DNA fragment will be affected by the insulator

Answer 1

Insulators are cis-regulatory DNA elements that can prevent the uncontrolled effect of enhancers or silencers, restricting their interactions with the promoters of the gene. Insulators have two main functions: i] Enhancer-blocking insulators prevent distal enhancers from acting on the promoter of the neighbouring genes. ii] Barrier insulators prevent silencing of euchromatin by the spread of neighbouring heterochromatin. Insulators prevents the imprented expression of IGF2 gene (Insulin-llike growth factor 2) by blocking the interaction of enhancer to IGF2 gene promoter. Thus only H19 gene (gene for long non-coding RNA) is expressed at IGF2-H19 imprented locus. Insulators are also known to regulate the expression of cell cycle regulation genes such as hTERT and C-MYC. The expression of other genes (BRCA1 and p53) encoding cell cycle regulators are also controlled by insulators.