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Gene
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A gene is the unit of hereditary
and carries inherited information
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Amazing Facts3 billion (3,000,000,000) letters in the DNA code in every cell in your body.
There is 6 feet of DNA in each of our cells packed into a structure only 0.0004
inches across (it would easily fit on the head of a pin).
There are 100 trillion (100,000,000,000,000) cells in the body
If all the DNA in the human body was put end to end it would reach to the sun
and back over 600 times (100 trillion x 6 feet divided by 93 million miles = 1200).
If we recited the genome at one letter per second for 24 hours a day it would take
a century to recite the book of life.
The vast majority of DNA in the human genome - 97% - has no known function.
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Genes who are you Exactly?
I am carried on a chromosome
I am The basic unit of heredity
Encode how to make a proteinDNARNA proteins
Proteins carry out most of life’s function.
When altered causes dysfunction of a protein
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Chromosome to Gene
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Genes per chromosome
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Gene structure
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Gene structure
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exon 2exon 1 exon npromotor
5‘UTR
3‘UTRProtein coding sequence
exon n-1
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How Function is done
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Our life is maintained by molecular network systems
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Molecular network system in a cell
Proteins play key roles in a living system
• Three examples of protein functions
• Catalysis:Almost all chemical reactions in a living cell are catalyzed by protein enzymes.
• Transport:Some proteins transports various substances, such as oxygen, ions, and so on.
• Information transfer:For example, hormones.
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Alcoholdehydrogense oxidizes alcohols to aldehydes or ketones
Hemoglobin carries oxygen
Insulin controls the amount of sugar in the blood
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TERTIARY STRUCTURE (fold)TERTIARY STRUCTURE (fold)
Genome
Expressome
Proteome
Metabolite
Functional GenomicsFrom gene to function
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Dilemma
• When there is a mutation in the gene, then it will change the codon, which will change which amino acid is called for which will change the conformation of the protein which will change the function of the protein. Genetic disorders result from mutations in the genome.
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Imagine
• Imagine that you accidentally broke one of your neighbor's windows.
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let us imagine with each other What will you do?
Stay silent: no one will ever find out that you are guilty, but the window doesn't get fixed.
Repair it with some tape: not the best long-term solution.
Put in a new window: not only do you solve the problem, but also you do the honorable thing.
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What is similar in gene therapy
I. Stay silent: ignore the genetic disorder and nothing gets fixed.
II. Try to treat the disorder with drugs or other approaches: depending on the disorder, treatment may or may not be a good long-term solution.
III. Put in a normal, functioning copy of the gene: if you can do this, it may solve the problem!
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How to fix it
A
B C a beneficial geneA
virus modified virus
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Gene therapy using an Adenovirus vector. A new gene is inserted into an adenovirus vector, which is used to introduce the modified DNA into a human cell. If the treatment is successful, the new gene will make a functional protein.
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A virus is found which replicates by inserting its genes into the host cell's genome. This virus has three genes - A, B and C.
Gene A encodes a protein which allows this virus to insert itself
into the host's genome.
Genes B and C actually cause the disease this virus is associated with.
Replace B and C with a beneficial gene. Thus, the modified virus could introduce your 'good gene' into the host cell's genome without causing any disease.
So we use the modified virus to fix the “broken window”
Gene Therapy
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Diseases
Which of the following diseases are current or potential targets of gene therapy?
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Acquired
Inherited diseases
a. Cancer b. AIDS c. Diabetes d. Parkinson’s
Disease
Ex
1-one gene
Cystic fibrosis
Severe combined immunodeficiency
Adenosine deaminase and purine nucleoside phosphorylase
2- gene therapy for cancer
3-gene therapy for cardiovascular diseases
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Diseases
• Acquired Inherited
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DiseasesGenetic diseases:
Type 1: Single locus (gene) is defective and responsible for
the disease, 100% heritable.
: Sickle cell anemia,
Hypercholesterolemia
Cystic fibrosis
Type 2: Polygenic traits, <100% heritable, may be dependent
on environmental factors and lifestyle.
Heart disease
Cancer
Diabetes
Alcoholism
Schizophrenia
Criminal behavior
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QUESTIONS
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What is Gene Therapy formal definition
It is a technique for correcting defective genes that are responsible for disease development
There are several approaches:1-A normal gene inserted to compensate for a nonfunctional gene.
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techniques
-An abnormal gene
changed with normal gene
An abnormal gene repaired through
selective reverse mutation
-Change the regulation of gene pairs
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• Insertion of genes into individual’s cell
• Or
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Tissue
To treat a disease
Hereditary disease in particular
Gene Therapy mainly aim to
• Supplement a defective mutant allele
• With a functional one
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• diseases treated by gene thereby
• Can be divided to
• inherited Acquired
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Diseases like
parkinsonism
AIDS
Diabetes