Download Gene Regulation in Cells

the case of
Gene Regulation in Cells
Background
Gene regulation is the process of turning genes on and off in the right cells, at the right times, and in the right
amounts. When a gene is turned on, the protein that it encodes is produced by the cell via transcription and
translation. Proteins are the molecular machines that carry out the functions that cells need to perform, so the
exact mix of proteins in a cell determines its cell fate (what kind of cell it is, for example making a neuron different
from a skin cell). Therefore, gene regulation links genotype (genetic information) and phenotype (observable
characteristics). The proteins that control gene regulation are transcription factors. They bind to DNA sequences
called enhancers. When bound together, an enhancer and transcription factors act as a genetic switch to turn a
gene on or off. (See box, “Gene Switches in Action,” Carroll et al., 2008).
Evolutionary changes to an enhancer will change the location, timing, or amount of gene expression without
changing the function of the gene itself. This can lead to new combinations of proteins in cells, and therefore to new
phenotypes for the animal. While many enhancers are conserved among closely related animals, examples of new,
lost, or modified enhancers have been discovered. You will read about multiple such examples in Carroll et al., 2008.
Eric Bertolino of the University of Chicago studies regulatory networks that dictate cell fate choices in the immune
system. Rebecca Spokony, a postdoc at the University of Chicago, is developing resources to study transcription
factors in Drosophila melanogaster. By attaching a green fluorescent protein tag to the transcription factors their
location can be studied visually and their genome-wide DNA binding patterns can be studied biochemically.
For more information, visit the following websites: igsb.org/people/rebecca-spokony,
http://www.igsb.org/ labs/kevin-white/ and http://mgcb.uchicago.edu/phd_program/faculty/singh/index.html.
Lesson Overview
Systems biologists are interested in understanding how the presence and absence of different molecules affect
protein synthesis. In this lesson, students will learn about gene regulation in cells and then apply this knowledge by
identifying analogous parts and processes in a given model—a city, factory, ecosystem, or other system. At the end
of the lesson, students should be able to articulate how their model is analogous to gene regulation in cells and its
relationship to systems biology: understanding cells as a functioning system can help us understand how systems
work in general (e.g. the functioning of a whole ecosystem).
The Field Museum • Chicago Center for Systems Biology
The Case of Gene Regulation in Cells • Page 1
Essential Questions
• Why is gene regulation important in cells?
• What would happen if there were not inducers or inhibitors in cells?
• How is the functioning of gene regulation analogous to an every day example, situation, or place?
Objectives
Students will…
• Describe the function of gene regulation, inducers, and inhibitors.
•Develop a model and label the parts and processes analogous to gene regulation in cells.
•Engage in scientific inquiry to strengthen skills of critical thinking, questioning, deductive reasoning, and the
scientific process.
•Relate this project to systems biology and understand the effect of gene regulation on living cells and the whole
organism.
Next Generation Science Standards
HS-LS1-1. C
onstruct an explanation based on evidence for how the structure of DNA determines the structure of
proteins which carry out the essential functions of life through systems of specialized cells.
HS-LS1-2. Develop and use a model to illustrate the hierarchical organization of interacting systems that provide
specific functions within multicellular organisms.
Common Core State Standards
CCSS.ELA-Literacy.SL.9-10.4 Present information, findings, and supporting evidence clearly, concisely, and logically
such that listeners can follow the line of reasoning and the organization, development, substance, and
style are appropriate to purpose, audience, and task.
Prerequisite Knowledge
• What is regulation and why it is important
• Understand transcription and translation
•Understand the role of inducers and inhibitors
•Important terms: DNA, RNA, protein, transcription, translation, inducer, inhibitor, ribosome, protein synthesis,
genotype, phenotype, analogy/analogous, gene experession, cell differentiation
Materials
• Large sheets of paper (1 per team)
• Markers and colored pencils (1 set per team)
•Carroll, S.B., Prud’homme, B., and Gompel, N. (2008). Regulating Evolution. Scientific American, May, 60-67.
http://www.ibdml.univ-mrs.fr/equipes/BP_NG/publications-files/Carroll2008.pdf (1 per student)
The Field Museum • Chicago Center for Systems Biology
The Case of Gene Regulation in Cells • Page 2
Time Frame
The time frame for this project is subjective. A total estimated time of 125–165 minutes is suggested. Teachers can
lengthen or shorten the time spent on each part of the project. An approximate time frame for each part is provided
within the procedure.
Assessment
• Informal assessment through discussions
• Poster and final presentation
• Lab journal or write up including questions answered during the project
Procedure
Part 1: Introduction (20-30 minutes)
•Review gene regulation in cells by having the students’ jigsaw (Break the students into small groups and assign
each member of a group a page or two of the article. After reading their assigned pages the students come
back to their groups and give an overview of their pages.) of the journal article Regulation Evolution, Scientific
American.
Part 2: Designing Models (75-90 minutes)
•Provide background information about models and analogies, what they are and why they are helpful in
illustrating complex concepts. For example, the human skeleton is like the framework of a house. Both give
structural support. The skeleton allows the human to stand upright and supports the body and its internal
organs; the framework of a house allows the house to stand upright without falling over and supports the roof
and all floors/levels inside of the house.
•Organize students in small groups. Each group should create a poster or blueprint of a model (city, factory,
ecosystem, or other system) analogous to the process of gene regulation. Posters should include a title and all
relevant parts and processes labeled (what it is, an explanation of its function, and its analogous part or process/
function within gene regulation).
Part 3: Presentation and Discussion (30-45 minutes)
• Have teams present their models.
•Conduct a summative discussion to connect the project with gene regulation in cells and how this relates to
systems biology: understanding the functioning of cells (cells as a functioning system) can help us understand
the workings of a system (e.g. the functioning of a whole ecosystem).
Funding and support provided by NIH & CCSB. The project described was supported by award number P50GM081892 from the National Institute of
General Medical Sciences. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National
Institute of General Medical Sciences of the National Institutes of Health.
The Field Museum • Chicago Center for Systems Biology
The Case of Gene Regulation in Cells • Page 3