Engler and Prantl system of classification in plant taxonomy
Genome editing
1. GENOME EDITING
Prepared by,
ADITHYA P BALAKRISHNAN
Reg. No: 04-AGRMA-01724-18
M. Sc. (Agri.)
Dept. of Genetics and Plant Breeding
C. P. C. A, S. D. A. U
Submitted to,
Dr. KAPIL TIWARI
Assistant Professor
Dept of GPB
S. D. A. U
2. CENTRAL DOGMA OF LIFE
DNA
RNA
PROTEIN
NATURAL DNA REPAIR MECHANISMS
Direct reversal
• Photoreactivation & Alkylation
ss Repair
• Excision repair & Mismatch
repair
ds Repair
• HR, NHEJ, Microhomology
mediated joining
Transcription
Translation
3. WHAT IS GENOME EDITING ?
The way of making specific changes to DNA of a cell or an organism
Also known as,
Gene editing/ Genome engineering
Results in: Altered gene expression and protein behavior
6. AVAILABLE TECHNIQUES
GENOME EDITING
TECHNIQUES
Conventional
genome
editing systems
Chemical
system
Protein based
nuclease
system
Homing
endonuclease
system
RNA-protein
based system
Techniques
in research
Conventional
homologous
recombination
ssODNs
homologous
recombination
Peptide NA
systems
Meganuclease
system
ZFN systems
TALEN systems
Adeno-
associated
virus (AAA)
systems
CRISPER
system
Type-1
CRISPER-Cas
Type-2
CRISPER-Cas
Type-3
CRISPER-Cas
ODN
techniques
Using novel
proteins
-Argonautes,
Integrases,
Recombinases
Synthetic
genomicsKhan, 2019
7. GENOME EDITING BY USING
CHIMERIC ENZYMES
DNA
Binding
Domain
Endonu
cleases
Domain
CHIMERIC
ENZYME/
DESIGNER
ENGINEERED
ENDONUCLEA
SES
8. BASIC STRUCTURE AND FUNCTION
OF ENGINEERED NUCLEASES
Double stranded breaks
Repair DSBs
9. MECHANISMS FOR REPAIR OF DSBs
Non Homologous End Joining
(NHEJ)
Two DNA ends ligated without
homology
Error-prone process
Chances of ‘indels’ (FS Mutations)
Predominates in the absence of
externally added homologous DNA
Homologous Recombination
(HR)
Resolves DSBs by replacing the
genetic material between two areas of
homology
Introduce exogenous
sequences/alternate alleles
13. Zinc Finger Nucleases System
Artificial endonuclease system
Consists of two domains:
DNA binding domain Endonucleases domain
• Zinc Finger Motif
• TF III of Xenopus leavis
• one ZF domain binds to three
nucleotides
• Non-specific type II restriction enzyme
• FokI (Flavobacterium okeanokoites)
• Cleave on dimerization (So, add half to one
ZFNs)
Dunn et al. 2014
14. Step by Step Zinc-Finger Nuclease-Induced Genome Editing
Khan, 2019
15. Methods for Construction
OPEN
Oligomerized pool engineering
Creating a pool of ZFAs, then
assessing them for use
Less efficient & Labour
intensive
CoDA
Context-dependent assembly
Individual ZFs were tested to
assess their target specificity
when placed in combination with
other ZFs
16. Transcription Activator-like Effector
Nucleases
Site specific artificial nucleases
Two domains:
DNA binding domain
Endonucleases domain• Transcription Activator-like Effectors
(TALEs)
• Xanthomonas
• 34 conserved proteins & repeat-
variable di residues (RVDs)
• One domain specifically bind to one nt
• Non-specific type II restriction enzyme
• FokI (Flavobacterium okeanokoites)
Dunn et al. 2014
21. Schematic Demonstrating the Concept of CRISPR/Cas9 Interactions Leading to the
Destruction of Viral Genome at the Selected Splice Site by the crRNA/gRNA
Khan, 2019
25. PROS and CONS
Safety risk
Ethical issues
Bioweapons
Reduced diversity
Immunotherapy
Cure genetic diseases
Drug development
Improve crops
26. REFERENCES
Dunn, D. A and Pinkert, C. A. (2014). Gene Targeting
Khan, S. H. (2019). Genome editing technologies: concept, pros and cons various
genome editing technologies and bioethical concerns for clinical applications
Jennifer A. Doudna and Emmanuelle Charpentier (2014). The newfrontier
ofgenome engineering with CRISPR-Cas9