Question 1
Multiple choiceEasy1 markIn a cell, cytosines in the promoter of gene P are methylated, while amino acids in histones in nucleosomes associated with gene H are methylated. Which interpretation of transcription is consistent with these tags?
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Answer: C. Cytosine methylation in a promoter represses transcription of the downstream gene. In contrast, methylation of histone amino acids in nucleosomes can either repress or activate transcription. A: Extends the two possible effects of histone methylation to promoter cytosine methylation. B: Reverses the effect of promoter cytosine methylation, although its histone statement is correct. D: Treats histone methylation as invariably repressive, excluding its possible activating effect. Remember: the effect of methylation depends on whether the tag is on promoter DNA or histones.