Question

For each mechanism of eukaryotic gene regulation, specify whether it is pre-transcriptional or post transcriptional

Methylation of CpG islands in the promoter

histone acetylation

RNA interference

Answer 1

1. Methylation of CpG islands in the promoter is pre-transcriptional gene regulation.

Methylation of cytosine of Cpg islands in the promoter often silence (inhibit) gene expression (transcription). Since it occurs in the DNA, it is a is pre-transcriptional gene regulation.

2. Histone acetylation is pre-transcriptional gene regulation.

Histone acetylation promotes gene expression as acetylation of histone relaxes DNA to make it available for binding of transcription factors. Since it occurs in the DNA, it is pre-transcriptional gene regulation.

3. RNA interference is post-transcriptional gene regulation.

RNA interference involves binding of small RNAs (e.g. microRNA) to mRNAs and promoting degradation of mRNA. Since it occurs in the mRNA, it is post-transcriptional gene regulation.