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Watch this animation to learn more about the use of p53 in fighting cancer.

Proto-oncogenes are positive cell-cycle regulators. When mutated, proto-oncogenes can become oncogenes and cause cancer. Overexpression of the oncogene can lead to uncontrolled cell growth. This is because oncogenes can alter transcriptional activity, stability, or protein translation of another gene that directly or indirectly controls cell growth. An example of an oncogene involved in cancer is a protein called myc. Myc is a transcription factor that is aberrantly activated in Burkett’s Lymphoma, a cancer of the lymph system. Overexpression of myc transforms normal B cells into cancerous cells that continue to grow uncontrollably. High B-cell numbers can result in tumors that can interfere with normal bodily function. Patients with Burkett’s lymphoma can develop tumors on their jaw or in their mouth that interfere with the ability to eat.

Cancer and epigenetic alterations

Silencing genes through epigenetic mechanisms is also very common in cancer cells. There are characteristic modifications to histone proteins and DNA that are associated with silenced genes. In cancer cells, the DNA in the promoter region of silenced genes is methylated on cytosine DNA residues in CpG islands. Histone proteins that surround that region lack the acetylation modification that is present when the genes are expressed in normal cells. This combination of DNA methylation and histone deacetylation (epigenetic modifications that lead to gene silencing) is commonly found in cancer. When these modifications occur, the gene present in that chromosomal region is silenced. Increasingly, scientists understand how epigenetic changes are altered in cancer. Because these changes are temporary and can be reversed—for example, by preventing the action of the histone deacetylase protein that removes acetyl groups, or by DNA methyl transferase enzymes that add methyl groups to cytosines in DNA—it is possible to design new drugs and new therapies to take advantage of the reversible nature of these processes. Indeed, many researchers are testing how a silenced gene can be switched back on in a cancer cell to help re-establish normal growth patterns.

Genes involved in the development of many other illnesses, ranging from allergies to inflammation to autism, are thought to be regulated by epigenetic mechanisms. As our knowledge of how genes are controlled deepens, new ways to treat diseases like cancer will emerge.

Cancer and transcriptional control

Alterations in cells that give rise to cancer can affect the transcriptional control of gene expression. Mutations that activate transcription factors, such as increased phosphorylation, can increase the binding of a transcription factor to its binding site in a promoter. This could lead to increased transcriptional activation of that gene that results in modified cell growth. Alternatively, a mutation in the DNA of a promoter or enhancer region can increase the binding ability of a transcription factor. This could also lead to the increased transcription and aberrant gene expression that is seen in cancer cells.

Questions & Answers

what are the two types of electron microscope
Sharlom Reply
light microscope and early microscope
Sama
Enzymes are biological catalyst which alter any reaction and protein in nature
Nkoue Reply
Thanks
Gaudi
Your welcome sir
Nkoue
guyz you enjoying
Royd
What is translation and transcription
Nkoue
Transcription is making RNA from DNA. Translation is going from RNA to proteins.
Eric
what is the definition of enzymes
Royd Reply
enzymes are biological catalyst that speed up chemical reaction.
Alale
What are enzymes?
Gaudi
Enzymes are made of proteins and lower the energy of activation. In other words, they bring things together which helps to lower the amount of energy for a reaction to go forward.
Eric
they are catalyses that speeds up chemical reaction.... e.g they break down the food we consume.
Azeez
what is a spirogyra
Talabi Reply
Spirogyra is a filamentous chlorophyte green algae of the order Zygnematales. It is named for the helical or spiral arrangement of the chloroplasts. That is characteristic of the genus. It is commonly found in freshwater habitats. And there are more than 400 species of Spirogyra in the world.
Eric
what is the mean of biology
Bello Reply
what is cell
Bello
A cell is the smallest living unit.
Eric
Hi I'm new in this group can someone please help with the list features shared by plants and charopytes that are not shared with most other eukaryotes
Wendy
what is eutrophication
Chinaza Reply
Show well labeled diagram of female reproductive organs
Lanlege Reply
phenotype is your big head
Amagiya Reply
The phenotype is the physical appearance or things you can see. Or the traits expressed by ones DNA.
Eric
phenotypes are appearance that can be seen and touched
Chidera
what is a dichotomous key
Moses Reply
explain the role of
Moses
Dichotomous key : Is the key that is use to classify or group an organism base on their common features
Alale
an amoeba is what kind of cellular organism?
Mercy Reply
It is a protizoa with bilayer membrane bound organelles. Therefore it is eukaryotic.
Eric
what is amoeba
Muhammad
amoeba is a unicellular organisms. Therefore it is made u of only one call.
Alale
what is phenotype
Muhammad
amoeba is a unicellular organism with one cell
Chinaza
name ten equipments found in soil science laboratory and their uses
AFANU Reply
daigram of connective tissue
Yunusa Reply
what is polarization
Finda Reply
in the concept of science, polarization involves light, radiation, magnetism moving in specific directions
Chidera
What is appendicular
GLORIA Reply
relating to or denoting an appendage or appendages.
Eric
Homeostasis definition
Ben Reply
can be defined as a steady of internal environment
Aliyu
MMMM!!!
Kaole
🙄
Aliyu
:-)
Kaole

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Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
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