Lecture 9 - Eukaryote Gene Regulation

Question 1

What are the three RNA polymerases that transcribe different nuclear genes in eukaryote cells and what are the genes that they transcribe?

Answer 1

• RNA polymerase I: Ribosomal RNA (rRNA) genes
• RNA polymerase II: Messenger RNA (mRNA) genes that code for polypeptides (proteins)
• RNA polymerase III: Small RNAs, such as transfer RNAs (tRNA) and 5s RNA genes

Question 2

How does the regulation of gene transcription by hormone receptors work?

Answer 2

Allosteric proteins, that undergo a conformational transition following binding of a ligand, a steroid hormone

Question 3

What are the sites of gene regulation in eukaryotic cells?

Answer 3

1) transcriptional initiation
2) processing of RNA: alternate splicing of exons, multiple 3’ cleavage sites, 5’ cap & poly(A) addition
3) mRNA transport
4) mRNA storage (e.g. eggs)
5) mRNA degradation
6) translation
7) protein modification (e.g. phosphorylation)
8) protein degradation (turnover)