Question

Describe one method of eukaryotic gene regulation that can happen in each of the following cases:

1. Transcription

2. After transcription is completed, before the transcript leaves the nucleus

3. After the transcript leaves the nucleus

4. Translation

Answer 1

1) in eukaryotes gene regulation occurs at multiple levels.

A) At transcription level-

This type of regulation depends on promoter present. If a gene has strong promoter, means it has TATA box, initiator sequence and down stream promter elements. Along with this all the enhancer sequence than the expression of the gene will be higher.

But if a gene lacks one of the promoter elements or presence of repressor than expression of gene will be less.

B) After transcription is completed, before the transcript leaves the nucleus-

This type of regulation occurs during transcription ( or RNA processing). Known as post transcriptional regulation occurs during conversion of henna in to mature mRNA.

These include capping , 3' poly A tail or at splicing.

mRNA which has 5 cspan or long 3 poly A tail are more stable and has more chances to get transcribed.

C) After the transcript leaves the nucleus-

In the cytosol stability is depend on presence of 3 and 5' UTR part in mRNA.

UTR , increase stability of mRNA more translation of protein  

D) translation- there may be miRNA or siRNA mediated regulation.

In presence of miRNA or siRNA expression of particular gene will be decreased, known as post transcriptional gene silencing.