in cancer cells one allele of the tumor suppressor gene p53

____ in cancer cells one allele of the tumor suppressor gene p53 is frequently mutated so that the protein is inactive, not produced, or deleted. The other allele will usually have 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 cytosine\'s are methylated. If the cancer cell DNA is sequenced what would be the anticipated results? Cytosine\'s in or near the promoter region will be methylated. Cytosine\'s in or near the promoter will not be methylated. Cytosine\'s in the coding region will have an increased methylation. There will be no differences in the methylation pattern of the promoter of p53 from a cancer cell and a normal cell DNA that contains actively transcribed genes would most likely contain chromatin in the closed configuration. DNA methylation usually activates gene expression. Feeding a specific diet to female mice may result in an increased proportion of pseudo agouti (darker) offspring if ____ the female carries the A^vy allele, ____ the offspring have the genotype A^vy ___ the transposon at the A^vy locus in the progeny is hyper methylated. Genetics and epigenetics are similar in that they affect phenotype. Compare and contrast genetics and epigenetics in terms of mitotic inheritance meiotic inheritance and reversibility of changes.

Solution

5: Answer :A : It has been mentioned that in cancer cells one allele of p53 is mutated and the other allele in spite of having an intact promoter,does not express the protein. Hence this indicates that the expression in the other allele is suppressed not by mutation but by methylation. Methylation generally occurs in CpG inslands in or around the promoter region and thus prevents transcription. Hence the answer for this question is A.

6. False: because active genes need various proteins to bind to the promoter region such as transcription factors, polymerase etc. Hence to facilitate the binding and movement of these proteins during transcription, an open conformation is required.

7. False : Methylation modifies the CpG inlands in or near the promoter regions, inhibiting the binding of transcription factors, polymerase etc. Hence preventing transcription.