In cancer cells one allele of a tumor suppressor gene called p53 is frequently mutated so that the protein is inactive,not produced,or deleted. The other allele usually has a normal sequence and the promoter remains intact,but the gene is not expressed. Sequencing with sodium bisulfite modification of DNA can be used to detect which cytosines are methylated. If cancer cell DNA is sequenced,which of the following results would be expected?

Question

In cancer cells one allele of a tumor suppressor gene called p53 is frequently mutated so that the protein is inactive,not produced,or deleted. The other allele usually has a normal sequence and the promoter remains intact,but the gene is not expressed. Sequencing with sodium bisulfite modification of DNA can be used to detect which cytosines are methylated. If cancer cell DNA is sequenced,which of the following results would be expected?

Quizplus · Accepted Answer

Methylation of cytosines in or near the promoter region can inhibit the binding of transcription factors to the DNA, preventing transcription initiation, and leading to gene silencing. In cancer cells, the normal allele of p53 is not expressed, which suggests that the promoter is methylated. Therefore, the expected result would be methylation of cytosines in or near the promoter region of p53 in cancer cell DNA sequencing.

In Cancer Cells One Allele of a Tumor Suppressor Gene