Question

An enhancer is surrounded by four genes (A, B, C and D) as shown below. An insulator lies between gene C and gene D. On the basis of the positions of the genes, the enhancer and the insulator, the transcription of which genes is most likely to be stimulated by the enhancer? Explain.
-------Gene A------Gene B------Enhancer------Gene C------Insulator-------Gene D---------

Answer 1

The activity of an enhancer will be obstructed in the condition where the insulator is situated between the enhancer and the promoter of the gene. As, it is given in the question, that insulator that supress the activity of enhancer is located between gene C and gene D. Gene A, Gene B, Gene C are situated before the enhancer sequence, so these gene will be transcribed but Gene D transcription will be halted because of insulator sequence. Hence, Gene A, Gene B, Gene C is most likely to be stimulated by the enhancer