extra time

Question 1

characteristics of enhancers

Answer 1

1. generally cis-acting
2. they are located up to 1 Mbp away from gene
3. can be upstream or downstream from the start site, even in introns
4. are orientation independent
5. often associate with genes abundantly expressed (i.e. immunoglobin and antibody genes)
6. some are tissue specific, interaction with tissue-specific elements
7. they don’t act on the promoter region itself, they bound by activator proteins which interact with the recruiting mediator complex
8. can be excised and inserted elsewhere in chromosome and still affect transcription
9. can also be present in exons of unrelated genes
10. sometimes they’re not located on same chromosome as gene they’re regulating

Question 2

why are enhancers important

Answer 2

1. important role in evolution of species
2. development biology: development, differentiation and growth of cells and tissues
3. invertebrate segmentation: creation of different zones
4. vertebrate patterning; body axis antero-posterior and left-right Gastrulation
5. development robustness: survival of fruit flies when environmental disturbances take place
6. development mechanisms: limb development, wing pattern evolution. Pigmentation