1. Gene Regulation

2. Regulation of gene expression
refers to the cellular control of the amount and timing of changes to the appearance of the functional product of a gene.
Basically, anything that can regulate for example
Chemical and structural modification of DNA or chromatin
Transcription
Post-transcriptional modification
mRNA degradation

3. Modification of DNA Chemical
Methylation of DNA by DNA methyltransferases
gene silencing
Able to maintain the gene in an inactive state
Very much eukaryotic event
Example: arabidopsis thaliana dna methylation

4. Modification of DNA Structural Histone acetylation.
Histone acetyltransferase enzymes (HATs)
Histone Deacetylases (HDACs)
dissociate the DNA from the histone complex, allowing transcription to proceed.

6. Regulation of transcription
Regulation of transcription controls when transcription occurs and how much RNA is created. Transcription of a gene by RNA polymerase can be regulated by at least five mechanisms:
Specificity factors
Repressors
General transcription factors
Activators
Enhancers

7. Specificity factors
alter the specificity of RNA polymerase for a given promoter or set of promoters, making it more or less likely to bind to them
Example: Glucocorticoid receptor

8. Repressor bind to operator
impeding RNA polymerase's progress along the strand, thus impeding the expression of the gene.
coded for by regulator genes

9. General transcription factor
protein transcription factors that have been shown to be important in the transcription of genes to mRNA templates.

10. Activators
DNA-binding protein that regulates one or more genes by increasing the rate of transcription.
Coactivators
Interact with basal transcription machinery
Act on chromatin bound to histones

11. Enhancers Distant DNA elements
Multiple binding sites for sequence specific transcriptional activators

12. Translational Control
mRNA localisation
mRNA translation
mRNA stability

13. Cytoplasmic localisation of mRNA
Microtubules and motor proteins transport mRNA
Microfilaments anchor mRNA

14. mRNA Translation
Mechanisms exist to alter rate of translation

15. mRNA stability
Capping
Splicing.
Addition of poly(A) tail

19. Splicing
removes the introns, noncoding regions that are transcribed into RNA, in order to make the mRNA able to create proteins.
Cells do this by spliceosome's binding on either side of an intron, looping the intron into a circle and then cleaving it off.
The two ends of the exons are then joined together

21. Post-translational Control
Proteasomes
Degradation of cellular protein that have been marked for destruction
Ubiquitination
Done by ubiquitin ligases