Understanding Gene Regulation: The Role of Epigenetics in Gene Expression Control
This comprehensive review explores gene regulation, focusing on how genes can be turned on and off through epigenetic mechanisms. By examining DNA structure, including the role of histones and epigenetic tags like acetyl and methyl groups, we can understand the dynamic nature of gene expression. Through various examples, including cell specialization and cancer, this review highlights the impact of the epigenome on organism development and function. Learn how environmental factors and cell signals shape gene activity across generations.
Understanding Gene Regulation: The Role of Epigenetics in Gene Expression Control
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Presentation Transcript
Reviewing Vocab… • GENE: a segment of DNA that codes for a particular protein/trait • An expressed gene is one that is being transcribed (i.e. it is turned to the “on” position and is being used to make proteins!) • A repressed gene is one that is not being transcribed (i.e. it is turned to the “off” position)
Demonstration • Observe the two DNA models – can you identify the histones? • What is different about the two models?
Video • http://learn.genetics.utah.edu/content/epigenetics/intro/
Vocabulary • Epigenome • Epigenetic Tags • What do these do to the physical structure of DNA? • What kinds of things shape your epigenome?
DNA structure and Regulation • http://learn.genetics.utah.edu/content/epigenetics/control/ • Watch what happens to the appearance of the DNA, the # of mRNA, # of proteins, and the appearance of the cell as you turn the knob.
True or False? Methyl and acetyl groups control gene expression by controlling access to DNA.
Lick your rats • http://learn.genetics.utah.edu/content/epigenetics/rats/
So what does this have to do with protein synthesis? • http://www.teachersdomain.org/asset/biot09_vid_epigenetics/ • http://www.pbs.org/wgbh/nova/teachers/body/epigenetics.html • http://www.pbs.org/wgbh/nova/body/epigenetics.html
30,000+ genes • Does each cell need to be using all 30,000 genes? (hint: cell specialization!) • Do you need to be using all 30,000 genes at all times? (hint: energy conservation!)
Regulation • “Controls” over gene expression • Variety of methods • One basic way is by modifying the structure of DNA
Epigenetics • http://learn.genetics.utah.edu/content/epigenetics/intro/
Epigenetics The development and maintenance of an organism is orchestrated by a set of chemical reactions that switch parts of the genome off and on at strategic times and locations. • Epigenetics is the study of these reactions and the factors that influence them.
For example… • Genes that control whether or not a cell gets to go through mitosis… • regularly turned on and off = cells only divide when needed. • Cancer cells = unregulated cell division = epigenetic profile looks different…
Epigenetic Tags • Acetyl and methyl groups • Chemicals that act as switches that determine gene expression without changing the underlying genetic code • Turn genes on or off in response to cell signals • Create a layer of control called the epigenome
Epigenome • Reacts to factors throughout your lifetime. • Can affect future generations too…
Regulation of Genes • Genes can be turned on or off • Off = not active, not making proteins • Tightly wound • DNA covered in methyl groups • On = active, making proteins • Not tightly wound • Acetyl groups attached to histones
Other ways to control gene expression… • Intronsvsexons • Activity -