<img src="https://d5nxst8fruw4z.cloudfront.net/atrk.gif?account=iA1Pi1a8Dy00ym" style="display:none" height="1" width="1" alt="" />
Skip Navigation
Our Terms of Use (click here to view) have changed. By continuing to use this site, you are agreeing to our new Terms of Use.

Eukaryotic Gene Regulation

Gene regulation in eukaryotes can occur at every step a gene takes to become a protein.

Atoms Practice
Estimated3 minsto complete
Practice Eukaryotic Gene Regulation
Estimated3 minsto complete
Practice Now
Turn In
Eukaryotic Gene Regulation

On or Off? On or Off? On or Off?

That is the key question. Gene regulation in eukaryotes is a highly regulated process usually involving many proteins, which either bind to each other or bind to the DNA.

Eukaryotic Gene Regulation

In eukaryotic cells, the start of transcription is one of the most complicated parts of gene regulation. There may be many regulatory proteins and regulatory elements involved. Regulation may also involve enhancers. Enhancers are distant regions of DNA that can loop back to interact with a gene’s promoter.

The TATA Box

Different types of cells have unique patterns of regulatory elements that result in only the necessary genes being transcribed. That’s why a skin cell and nerve cell, for example, are so different from each other. However, some patterns of regulatory elements are common to all genes, regardless of the cells in which they occur. An example is the TATA box, so named because it has a core sequence of TATAAA. This is a regulatory element that is part of the promoter of most eukaryotic genes. A number of regulatory proteins bind to the TATA box, forming a multi-protein complex. It is only when all of the appropriate proteins are bound to the TATA box that RNA polymerase recognizes the complex and binds to the promoter. Once RNA polymerase binds, transcription begins. 

Regulation During Development

The regulation of gene expression is extremely important during the development of an organism. Regulatory proteins must turn on certain genes in particular cells at just the right time so the organism develops normal organs and organ systems. Homeobox genes are an example of genes that regulate development. They code for regulatory proteins that switch on whole series of major developmental genes. In insects, homeobox genes called hox genes ensure that body parts such as limbs develop in the correct place. Figure below shows how a mutation in a hox gene can affect an insect’s development. Other organisms, including humans, also have hox genes. 

Effect of Hox gene mutation in fruit fly

Effect of Hox Gene Mutation. Scientists caused a mutation in a hox gene of this fruit fly. As a result of the mutation, a leg grew out of its head where an antenna should have developed.

Gene Expression and Cancer

The mutations that cause cancer generally occur in two types of regulatory genes: tumor-suppressor genes and proto-oncogenes (see Figure below). These genes produce regulatory proteins that control the cell cycle. When the genes mutate, cells with mutations divide rapidly and without limits, potentially resulting in a tumor and cancer.

Flowchart of how cancer develops

How Cancer Develops. This flow chart shows how a series of mutations in tumor-suppressor genes and proto-oncogenes leads to cancer.




  • Regulation of transcription in eukaryotes is generally more complex than in prokaryotes. It involves unique regulatory elements in different cells as well as common regulatory elements such as the TATA box.
  • Regulation is especially important during development. It may involve regulatory genes such as homeobox genes that switch other regulatory genes on or off.
  • Mutations in regulatory genes that normally control the cell cycle cause cancer.


  1. Identify the TATA box and its function in transcription.
  2. What is a homeobox gene?
  3. Why is gene regulation especially important during development?
  4. What are tumor-suppressor genes and proto-oncogenes?
  5. Sketch how an insect with a mutated hox gene might look. Explain your sketch. 

Notes/Highlights Having trouble? Report an issue.

Color Highlighted Text Notes
Please to create your own Highlights / Notes
Show More



Sites on the DNA strand that are bound by activators; brings a transcription factor to the initiation complex.

homeobox gene

Gene that codes for regulatory proteins that control gene expression during development.

hox gene

Homeobox gene; determines the basic structure and orientation of an organism.


Regulatory genes that help control cell division; when mutated can cause cancer.

TATA box

Regulatory element that is part of the promoter of most eukaryotic genes; has a core sequence of TATAAA.

tumor-suppressor genes

Regulatory genes that prevent cells with damaged DNA from dividing; when mutated can cause cancer.

Image Attributions

Explore More

Sign in to explore more, including practice questions and solutions for Eukaryotic Gene Regulation.
Please wait...
Please wait...