Skip to main content

Gene Therapy – Detailed Notes


Gene Therapy – Detailed Notes


Definition

Gene therapy is a therapeutic technique in which genetic material (DNA or RNA) is introduced, removed, or modified in a patient’s cells to treat or prevent genetic disorders and diseases by correcting defective genes or providing new functional genes.

Basic Concept

Many diseases occur due to mutation, deletion, or malfunction of genes.
Gene therapy aims to:
Replace a defective gene
Add a functional gene
Silence or inhibit a harmful gene
It works at the molecular level, targeting the root cause of disease rather than symptoms.


Types of Gene Therapy


1. Somatic Gene Therapy

Gene transfer into somatic (body) cells.
Effects are not inherited.
Most widely used and ethically accepted.
Examples:
Cystic fibrosis, cancer therapy, SCID

2. Germline Gene Therapy
Gene transfer into germ cells (sperm/egg) or early embryos.
Genetic changes are heritable.
Ethically restricted and banned in many countries.
Approaches of Gene Therapy
1. Gene Replacement Therapy
Defective gene is replaced by a normal functional gene.
2. Gene Addition Therapy
A new gene is added without removing the defective one.
3. Gene Silencing Therapy
Harmful gene expression is suppressed using:
siRNA
antisense oligonucleotides
CRISPR interference

4. Gene Editing

Precise correction of genes using:
CRISPR-Cas9
TALENs
Zinc-finger nucleases
Delivery Methods of Gene Therapy

A. Viral Vectors

Viruses modified to be non-pathogenic and used as gene carriers.
Vector
Features
Applications
Retrovirus
Integrates into genome
Cancer, SCID
Lentivirus
Infects dividing & non-dividing cells
HIV, genetic disorders
Adenovirus
High expression, non-integrating
Cancer therapy
AAV
Low immunogenicity
Eye and muscle diseases
B. Non-Viral Methods
Liposomes (lipofection)
Electroporation
Naked DNA injection
Gene gun (biolistics)

Strategies of Gene Delivery

1. Ex Vivo Gene Therapy
Cells removed from patient
Genetically modified in laboratory
Reintroduced into patient
Example: SCID treatment

2. In Vivo Gene Therapy

Gene directly delivered into patient’s body
Example: Eye gene therapy (retinal disorders)
Steps Involved in Gene Therapy
Identification of defective gene
Cloning of therapeutic gene
Selection of suitable vector
Gene delivery to target cells
Expression of therapeutic gene
Monitoring for safety and efficacy


Applications of Gene Therapy

1. Genetic Disorders
Severe Combined Immunodeficiency (SCID)
Hemophilia
Cystic fibrosis
Muscular dystrophy
2. Cancer
Tumor suppressor gene delivery (p53)
Suicide gene therapy
Immunogene therapy
3. Infectious Diseases
HIV gene therapy
Hepatitis
4. Neurological Disorders
Parkinson’s disease
Alzheimer’s disease

Advantages

Treats disease at genetic level
Long-lasting or permanent cure
Highly specific
Reduces dependency on drugs
Potential to cure inherited disorders


Limitations

Immune response against vectors
Risk of insertional mutagenesis
High cost
Ethical concerns
Limited efficiency in some tissues
Ethical, Legal, and Social Issues
Germline gene therapy ethics
Gene editing in embryos
Accessibility and affordability
Long-term safety concerns
Genetic enhancement misuse


Recent Advances


CRISPR-Cas9 gene editing
CAR-T cell therapy
RNA-based therapies
Personalized gene therapy
Examples of Approved Gene Therapies
Luxturna – inherited retinal disease
Zolgensma – spinal muscular atrophy
CAR-T therapy – leukemia and lymphoma

Conclusion

Gene therapy represents a revolutionary approach in modern medicine, offering potential cures for genetic and chronic diseases. Although challenges such as safety, cost, and ethical issues remain, advances in gene editing and vector technology continue to improve its effectiveness and clinical success.



Gene therapy is used to:
A) Remove proteins
B) Modify genetic material
C) Destroy cells
D) Inhibit enzymes
Answer: B
Gene therapy treats disease by:
A) Drug action
B) Surgical removal
C) Correcting defective genes
D) Vaccination
Answer: C
Gene therapy acts at the:
A) Cellular level
B) Tissue level
C) Molecular level
D) Organ level
Answer: C
Genetic material used in gene therapy includes:
A) DNA only
B) RNA only
C) DNA or RNA
D) Proteins only
Answer: C
Replacement of a faulty gene is called:
A) Gene silencing
B) Gene replacement
C) Gene suppression
D) Gene knockout
Answer: B
Types of Gene Therapy
Gene therapy performed on body cells is called:
A) Germline gene therapy
B) Somatic gene therapy
C) Embryonic gene therapy
D) Reproductive gene therapy
Answer: B
Changes in somatic gene therapy are:
A) Heritable
B) Non-heritable
C) Permanent in offspring
D) Transmitted to next generation
Answer: B
Germline gene therapy affects:
A) Only patient
B) Only parents
C) Future generations
D) Cancer cells
Answer: C
Germline gene therapy is:
A) Widely accepted
B) Ethically restricted
C) Commonly practiced
D) Approved worldwide
Answer: B
Most current clinical gene therapy trials use:
A) Germline therapy
B) Somatic therapy
C) Embryonic therapy
D) Reproductive therapy
Answer: B
Approaches & Strategies
Addition of a normal gene without removing faulty one is:
A) Gene replacement
B) Gene addition
C) Gene deletion
D) Gene knockout
Answer: B
Suppression of harmful gene expression is called:
A) Gene addition
B) Gene silencing
C) Gene replacement
D) Gene activation
Answer: B
Tools used for gene editing include:
A) CRISPR-Cas9
B) TALENs
C) Zinc-finger nucleases
D) All of the above
Answer: D
Ex vivo gene therapy involves:
A) Direct injection into patient
B) Modification outside the body
C) Germline manipulation
D) Embryo editing
Answer: B
In vivo gene therapy involves:
A) Cell culture only
B) Direct delivery into patient
C) Gamete modification
D) Cloning
Answer: B
Vectors & Delivery Systems
Most commonly used vectors are:
A) Bacterial plasmids
B) Viral vectors
C) Ribosomes
D) Enzymes
Answer: B
Retroviral vectors integrate into:
A) Cytoplasm
B) Host genome
C) Mitochondria
D) Ribosomes
Answer: B
Lentiviruses can infect:
A) Dividing cells only
B) Non-dividing cells only
C) Both dividing and non-dividing cells
D) Bacterial cells
Answer: C
Adenoviral vectors generally:
A) Integrate into genome
B) Do not integrate into genome
C) Cause mutations always
D) Are non-immunogenic
Answer: B
AAV vectors are preferred because of:
A) High toxicity
B) Low immunogenicity
C) Large genome size
D) Rapid degradation
Answer: B
Non-Viral Methods
Liposome-mediated gene delivery is called:
A) Electroporation
B) Lipofection
C) Biolistics
D) Microinjection
Answer: B
Electroporation introduces DNA using:
A) Chemical treatment
B) Electric pulses
C) Heat shock
D) Ultrasound
Answer: B
Gene gun method is also called:
A) Lipofection
B) Microinjection
C) Biolistics
D) Transduction
Answer: C
Naked DNA delivery is mainly used in:
A) Muscles
B) Brain
C) Liver only
D) Kidney
Answer: A
Non-viral methods generally have:
A) Higher immunogenicity
B) Lower safety
C) Lower efficiency than viral vectors
D) Higher mutation rates
Answer: C
Applications
First successful gene therapy treated:
A) Hemophilia
B) SCID
C) Cystic fibrosis
D) Cancer
Answer: B
Gene therapy for cancer may involve:
A) Tumor suppressor genes
B) Suicide genes
C) Immune activation
D) All of the above
Answer: D
CAR-T cell therapy is used for:
A) Genetic disorders
B) Cancer treatment
C) Viral infection
D) Diabetes
Answer: B
Gene therapy in retinal disorders uses:
A) Retrovirus
B) Adenovirus
C) AAV
D) Lentivirus
Answer: C
Hemophilia gene therapy targets:
A) Clotting factor genes
B) Insulin genes
C) Antibody genes
D) Enzyme genes
Answer: A
Advantages
Main advantage of gene therapy is:
A) Temporary relief
B) Symptomatic treatment
C) Treats root cause of disease
D) Low cost
Answer: C
Gene therapy can provide:
A) Permanent cure
B) Short-term cure only
C) No cure
D) Temporary suppression only
Answer: A
Gene therapy reduces dependence on:
A) Surgery
B) Antibiotics
C) Long-term drug therapy
D) Vaccines
Answer: C
Target specificity of gene therapy is:
A) Low
B) Moderate
C) High
D) Random
Answer: C
Personalized medicine is possible due to:
A) Vaccines
B) Gene therapy
C) Antibiotics
D) Hormone therapy
Answer: B
Limitations & Ethics
Major risk of gene therapy is:
A) Infection
B) Insertional mutagenesis
C) Vitamin deficiency
D) Allergy only
Answer: B
Immune response occurs mainly against:
A) DNA
B) RNA
C) Viral vectors
D) Proteins
Answer: C
High cost is a:
A) Benefit
B) Ethical issue
C) Technical advantage
D) Safety feature
Answer: B
Germline gene therapy is controversial because it:
A) Is expensive
B) Affects future generations
C) Is inefficient
D) Requires viruses
Answer: B
Gene therapy trials require strict:
A) Laboratory rules
B) Ethical guidelines
C) Political approval
D) Trade regulations
Answer: B
Recent Advances & General
CRISPR-Cas9 is used for:
A) Gene cloning
B) Gene editing
C) Protein synthesis
D) DNA sequencing
Answer: B
RNA-based gene therapy includes:
A) siRNA therapy
B) mRNA therapy
C) Antisense therapy
D) All of the above
Answer: D
Zolgensma is approved for treating:
A) Cancer
B) Spinal muscular atrophy
C) Hemophilia
D) SCID
Answer: B
Luxturna is used to treat:
A) Muscular dystrophy
B) Retinal disease
C) Diabetes
D) Cancer
Answer: B
CAR-T therapy modifies:
A) B cells
B) T cells
C) Stem cells
D) Neurons
Answer: B
Final
Gene therapy is an example of:
A) Preventive medicine
B) Molecular medicine
C) Herbal medicine
D) Surgical therapy
Answer: B
Long-term expression in gene therapy requires:
A) Protein injection
B) Gene integration
C) Drug administration
D) Vaccination
Answer: B
Safety of gene therapy depends mainly on:
A) Vector choice
B) Age of patient
C) Diet
D) Temperature
Answer: A
Gene therapy is still limited by:
A) Technology
B) Ethical issues
C) Cost
D) All of the above
Answer: D
Future of gene therapy is closely linked with:
A) Antibiotics
B) Vaccines
C) Gene editing technologies
D) Herbal medicine
Answer: C





Comments

Post a Comment

Popular Posts

Electroporation – Detailed Notes

Electroporation – Detailed Notes Definition : Electroporation is a physical method of gene transfer in which cells are exposed to a brief, high-voltage electric pulse, creating temporary pores in the cell membrane. This allows DNA, RNA, proteins, or other molecules to enter the cytoplasm. It is widely used in bacteria, yeast, plant protoplasts, and mammalian cells. Key Concept: The electric field destabilizes the membrane, making it permeable to macromolecules. 1. Principle Cells are suspended in a conductive medium. A brief electrical pulse induces transient pores in the plasma membrane. DNA or other molecules present in the medium enter the cell through these pores. Membrane reseals after the pulse, and the molecule is retained inside the cell. Advantages of Principle: Direct and rapid. Works in many cell types. Does not require chemical carriers or viral vectors. 2. Materials Required Cells – bacterial, yeast, plant protoplasts, mammalian cells. DNA/RNA/other macromolecule – purifie...
Post a Comment
Read more

Protein Structure Database (PDB)

Protein Structure Database (PDB) Introduction The Protein Structure Database (PDB) is the primary global repository for the three-dimensional (3D) structures of biological macromolecules such as proteins, nucleic acids, and protein–ligand complexes. These structures are determined experimentally using techniques like X-ray crystallography, Nuclear Magnetic Resonance (NMR) spectroscopy, and Cryo-Electron Microscopy (Cryo-EM). PDB plays a vital role in understanding: Protein structure and function Molecular interactions Drug discovery and design Structural biology and bioinformatics History and Development Established in 1971 Founded by Brookhaven National Laboratory (USA) Initially contained only 7 protein structures Now maintained by the Worldwide Protein Data Bank (wwPDB) Members of wwPDB RCSB PDB (USA) PDBe (Europe) PDBj (Japan) BMRB (Biological Magnetic Resonance Data Bank) Objectives of PDB To collect, store, and distribute 3D structural data of biomolecules To provide free and ope...
Post a Comment
Read more

Information retrieval from databases - search concepts, Tools for searching, homology searching, finding Domain and Functional site homologies

Information retrieval from databases - search concepts, Tools for searching, homology searching, finding Domain and Functional site homologies Information Retrieval from Databases 1. Introduction Information retrieval in bioinformatics refers to the process of extracting relevant biological data (DNA, RNA, protein sequences, structures, or functional information) from databases. Aim : Identify sequences, functions, or structural features for analysis, comparison, and annotation. Databases can be primary (raw sequence data) or secondary/derived (annotated, processed data). 2. Search Concepts in Biological Databases 2.1 Types of Searches Exact Match Search Returns results only if the query exactly matches database entries. Useful for known accession numbers or IDs. Pattern/Keyword Search Searches based on specific motifs, keywords, or annotations. Example: “kinase domain,” “signal peptide.” Similarity/Homology Search Detects sequences similar to the query based on sequence alignment. Use...
Post a Comment
Read more

π“†ž Western Blotting Notes

Western Blotting (Immunoblotting) ❥ π“†ž❥ π“†ž❥ π“†ž❥ π“†ž❥ π“†ž❥ π“†ž❥ π“†ž❥ π“†ž❥ π“†ž❥  Introduction Western blotting, also known as immunoblotting, is a widely used analytical technique for the detection, identification, and quantification of specific proteins in a complex biological sample. The technique combines protein separation by gel electrophoresis with specific antigen–antibody interaction. The method was developed by Towbin et al. (1979) (Burnette 1981---its group work) and is called “Western” in analogy to Southern blotting (DNA) and Northern blotting (RNA). Principle The principle of Western blotting involves: Separation of proteins based on molecular weight using SDS-PAGE Transfer (blotting) of separated proteins onto a membrane Specific detection of the target protein using primary and secondary antibodies Visualization using enzymatic or fluorescent detection systems πŸ‘‰ Antigen–antibody specificity is the core principle of Western blotting. Steps Involved in Western Blotting 1. Sa...
Post a Comment
Read more

••CLASSIFICATION OF ALGAE - FRITSCH

      MODULE -1       PHYCOLOGY  CLASSIFICATION OF ALGAE - FRITSCH  ❖F.E. Fritsch (1935, 1945) in his book“The Structure and  Reproduction of the Algae”proposed a system of classification of  algae. He treated algae giving rank of division and divided it into 11  classes. His classification of algae is mainly based upon characters of  pigments, flagella and reserve food material.     Classification of Fritsch was based on the following criteria o Pigmentation. o Types of flagella  o Assimilatory products  o Thallus structure  o Method of reproduction          Fritsch divided algae into the following 11 classes  1. Chlorophyceae  2. Xanthophyceae  3. Chrysophyceae  4. Bacillariophyceae  5. Cryptophyceae  6. Dinophyceae  7. Chloromonadineae  8. Euglenineae    9. Phaeophyceae  10. Rhodophyceae  11. Myxophyce...
Post a Comment
Read more

✩‧₊ Plaque Blotting Technique

Plaque Blotting Technique *ੈ✩‧₊˚༺☆༻*ੈ✩‧₊˚*ੈ✩‧₊˚༺☆༻*ੈ✩‧₊˚ Introduction Plaque blotting is a molecular biology screening technique used to identify specific DNA or RNA sequences present in bacteriophage plaques formed on a bacterial lawn. It is especially useful in the screening of recombinant phage libraries such as Ξ» (lambda) phage genomic or cDNA libraries. This technique combines: Plaque assay (to isolate individual phage clones) Blotting technique (to transfer nucleic acids onto a membrane) Hybridization (to detect specific sequences using labeled probes) Principle of Plaque Blotting The principle of plaque blotting is based on nucleic acid hybridization. Each plaque represents a clone of phage particles containing identical DNA. DNA from phage particles in plaques is: Released Denatured into single strands Transferred onto a nitrocellulose or nylon membrane The membrane is incubated with a labeled DNA/RNA probe complementary to the target sequence. Hybridization between probe and t...
Post a Comment
Read more