OCPEG_Control

1 EJC H2 Biology T1W3 Control of Prok and Euk Genomes I Control of Prokaryotic and Eukaryotic Genomes I I 1. Introduction If you extract the genome from two different cells of an organism and analyse them, you will find that they are identical. They contain the same number and type of genes. We know that the expressed proteins determine the specific function of the individual different cells. By extrapolation, this means that if all the genes were expressed into functional protein s in each cell , there should be no difference in how these two c ells should look or function. How then do both cells have distinct characteristics and specific functions? We will look at the concept of gene regulation to derive the answer in part 2 of our lecture series. In order to understand the gene regulation mech anisms in both the eukaryotic and prokaryotic genomes (with the focus on eukaryotic genome control as outlined in LO2j), a clear understanding of the mechanisms of gene expression in both must be first learnt. Thus, a snapshot of the overarching structure of this lecture series is as such: 1. Brief overview of gene expression in Prokaryotes and Eukaryotes 2. The various stages of gene expression in Eukaryotes and the associated gene regulation mechanisms involved (covered in greater detail). 3. The various stages of gene expression in Prokaryotes and the associated gene regulation mechanisms involved (covered in less detail). 4. A summary table comparing the control of Prokaryotic and Eukaryotic Genomes (to consolidate understanding and as a side-by-side reference) 2. Learning Outcomes 2 (j) Explain how differential (i.e. spatial and temporal) gene expression in eukaryotes can be regulated at different levels: i. chromatin level (histone modification and DNA methylation) ii. transcriptional level (control elements, such as promoters, silencers and enhancers, and proteins, such as transcription factors and repressors) iii. post-transcriptional level (processing of pre -mRNA in terms of splicing, polyadenylation and 5’ capping) iv. translational level (half-life of RNA and initiation of translation) post-translational level (biochemical modification and protein degradation) 3. References Campbell, N.A. and Reece, J.B. (2008). Biology, 8th edition. Pearson.

2 EJC H2 Biology T1W3 Control of Prok and Euk Genomes I 4. Organisation of Lecture Content Introduction 1 2. Learning Outcomes 1 3. References 1 4. Organisation of Lecture Content 2 5. Introduction to Gene Regulation 4 6. Brief Overview of Transcription and Translation in Prokaryotes and Eukaryotes 7 7. Eukaryotic Gene Expression and Regulation 8 A. At the Genome Level 8 A1 Chromatin Modification 8 A1.1 Chromatin remodelling complex 9 A1.2 DNA Methylation 10 A1.3 Acetylation/Deacetylation of Histones 11 A2 Gene Amplification 12 B. At the Tr