Suggested Reading

These brief articles are a supplement to the readings from your textbook on Gene Regulation. You do not have to finish these articles today, but they will help you understand gene regulation at a deeper level. They also make great references for your next milestone paper.

• Regulation of Transcription and Gene Expression in Eukaryotes
• Operons and Prokaryotic Gene Regulation
• Positive Transcription Control: The Glucose Effect
• Negative Transcription Regulation in Prokaryotes
• Obesity, Epigenetics, and Gene Regulation
• Environmental Influences on Gene Expression

• Do we express all of our genes at the same time? Why?
• Do we need all of our genes expressed all the time? Why?
• Why do we have so many genes?

These are just a few of the questions you need to start asking yourself. Humans have hundreds of thousands of genes. Many are needed all the time (constitutive), but others are only needed when the cell get’s certain signals. So how do we control the expression of all this genetic knowledge?

During mitosis, for example, did you see the production of DNA polymerase and the replication complex during the start of G1, or did you only see it after you passed the first restriction point? Do we keep DNA polymerase around just in case we are going to do some nuclear division? or do we unlock its expression only when needed?

Consider: The first restriction point determines if you are going to prep for division. When you have enough cyclin-dependent kinase available, you pass the restriction point. CDK signals the cell to get ready for division. How does this signal work? It changes gene expression (i.e., we activate regulated genes).

Think about the human body and homeostasis. Think about hormones. Are you always producing everything, or do you need to trigger some events? Could that trigger then be a regulated gene?

Remember that you need at minimum the equivalent of 4ATP per amino acid incorporated into a protein. Add to this 1 ATP equivalent for each nucleotide during transcription. You should quickly realize that gene expression is energy expensive.
Your goal today is to start reading about gene regulation, and more specifically, come to an understanding of the necessity of gene regulation.

Daily Challenge

Why do we need gene regulation? Today, reflect on the need and use of gene regulation. Why would an organism need to have some genes that it could turn on or off? Why would you need to control gene expression? Can the environment affect gene regulation? Can gene regulation affect evolution?

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