Biotech Articles
Publish Your Research Online
Get Recognition - International Audience

Request for an Author Account   |   Login   |   Submit Article
 
 
HOME FAQ TOP AUTHORS FORUMS PUBLISH ARTICLE
 
 

Zinc Finger Nucleases: A Molecular tool for Targeted Genetic Alterations

BY: Dr. Kiran B. Gaikwad | Category: Genetics | Submitted: 2015-01-04 23:44:44
       Author Photo
Article Summary: "Zinc Finger Nucleases (ZFNs) can effectively and precisely manipulate the genome of plant, animal and insect species. These modifications have resulted in understanding of gene function, gene integration, gene disruption, mutagenesis and in treatment of various diseases or disorders including HIV.."


Share with Facebook Share with Linkedin Share with Twitter Share with Pinterest Email this article
     


Every protein molecule has particular structure; likewise zinc finger is also a small protein structural motif, characterized by one or more zinc ions. The coordination between these zinc ions provides stability to the folds. Zinc finger was first identified in African fog Xenopus laevis (Klug and Rhodes 1987). In routine, zinc fingers coordinate zinc ions with pairs of cysteine and histidine residue in amino acid chain. The most important application of zinc finger is development of zinc finger nucleases (ZFNs). ZFNs are artificially synthesized rare cutting restriction enzymes which are developed by fusing zinc finger DNA binding domain with a DNA cleavage domain most specifically a type II restriction enzyme Fok I.

DNA cleavage domain: in order to cleave a DNA, the cleavage domain must dimerize, means, it should have two identical structural subunits. Therefore, two ZFNs are required to target non palindromic DNA site. These two ZFNs monomers bind to DNA target sequence in reverse orientation.

DNA binding domain: DNA binding domain of each ZFN contains 3-4 individual fingers, each capable of recognizing 3-bp long sequence. Thus, a heterodimer ZFN, composed of two 9-bp-long DNA binding domains will recognize an approximately 24-bp target sequence (Weinthal et al 2010)

Applications: ZFNs can be used to induce double stranded breaks (DSBs) in specific DNA sequence. A desired homologous donor DNA segment then could be inserted in this break followed by homologous recombination, which leads to tagged gene replacement. On the other hand, the DSBs in former DNA segment could be joined by non-homologous end joining (NHED), which leads to targeted mutagenesis. Important applications of ZFNs are as follows.


A. Debilitate dominant mutation in heterozygous individuals: ZFNs can be used to incapacitate dominant mutations in heterozygous individuals by making DSBs in the DNA in mutant allele. As discussed earlier, the DSB in DNA could be joined by NHEJ. If this joining happens perfect then there would not be any mutation.

B. Modifications of disease/ disorder causing alleles: ZFNs have positive role to play in modification of disease/ disorder causing alleles specifically the disorders caused by dinucleotide repeat expansion. It's a kind of mutation where trinucleotide ( e.g. CAG repeat, CGG repeat) repeat in certain genes exceeds the normal e.g. 230 to 4000 CGG repeat in X chromosome cause fragile X syndrome, Huntington's syndrome is caused by CAC repeat. ZFNs can specifically bind to these repeats and could generated DSBs, which leads to shortening of repeats. These short length trinucleotide repeats could be less dangerous (Mittelman et al 2009).

C. New gene addition: addition of desired gene at desired location in the host genome without causing cell injury or mutagenesis is the success of gene therapy. A designed ZFNs having non-specific cleavage domain of Fok I endonuclease with zinc finger protein could make a site specific DSB and with the help of homologous recombination a gene of interest could be inserted at this position (Kandavelou and Chandrasegaran 2008).

Problems Associated:

Cleavage of non-specific target site: it leads to;

a. Double stranded breaks at several locations which could results in chromosome segment translocations and other structural abnormalities

b. Integration of desired DNA in non-specific site could results in altered protein production which could be toxic / lethal for the individual.


REFERENCES:

1. Kandavelou K; Chandrasegaran S (2008). "Plasmids for Gene Therapy". Plasmids: Current Research and Future Trends. Caister Academic Press

2. Klug A, Rhodes D (1987). "Zinc fingers: a novel protein fold for nucleic acid recognition". Cold Spring Harb. Symp. Quant. Biol. 52: 473-82

3. Mittelman, D; Moye, C; Morton, J; Sykoudis, K; Lin, Y; Carroll, D; Wilson, JH (2009-06-16). "Zinc-finger directed double-strand breaks within CAG repeat tracts promote repeat instability in human cells". Proceedings of the National Academy of Sciences of the United States of America 106 (24): 9607-12

4. Weinthal, D., Tovkach, A., Zeevi, V., & Tzfira, T. (2010). Genome editing in plant cells by zinc finger nucleases. Trends in plant science, 15(6), 308-321.


About Author / Additional Info:
Scientist at Division of Genetics, Indian Agricultural research Institute. Presently doing research on identifying QTLs for genotype x management interaction for resource use efficiency in wheat.

Search this site & forums
Share this article with friends:



Share with Facebook Share with Linkedin Share with Twitter Share with Pinterest Email this article

More Social Bookmarks (Digg etc..)


Comments on this article: (0 comments so far)

Comment By Comment

Leave a Comment   |   Article Views: 1692



Additional Articles:

•   Interface of Agricultural Growth and Farmers' Income in India

•   Importance of Genomics

•   Immunologist or Allergist as a Career Option

•   Biotechnology in Animal Feed and Feeding




Latest Articles in "Genetics" category:
•   The Science and History of Genetics. How It Predicts the Genetic Code

•   Telomeres: Is It Responsible For Ageing and Cancer?

•   Human Genetic Engineering,its Methods and Ethics

•   Gene Mutation And Cancer

•   DNA Technology Used in Forensics

•   DNA Fingerprinting: Uses and Methods Involved

•   Treatment of Genetic Diseases by Gene Therapy

•   Human Intelligence and Genetics

•   Ethical Issues Related to Human and Animal Cloning

•   Mitochondrial DNA and Forensic

•   DNA Footprinting and Gene Sequencing

•   Biotechnology and Types of Cloning

•   Designer Babies:Method and Ethical Issues

•   Prenatal Diagnosis: Non-invasive and Invasive Techniques

•   What are the Benefits of Genetic Engineering?

•   The Advantages and Disadvantages of Genetic Engineering in Humans

•   Types of Genetic Disorders

•   Bovine Somatotropin: A Growth Hormone

•   Advantages and Disadvantages of Genetically Modified Food



Important Disclaimer: All articles on this website are for general information only and is not a professional or experts advice. We do not own any responsibility for correctness or authenticity of the information presented in this article, or any loss or injury resulting from it. We do not endorse these articles, we are neither affiliated with the authors of these articles nor responsible for their content. Please see our disclaimer section for complete terms.
Page copy protected against web site content infringement by Copyscape
Copyright © 2010 biotecharticles.com - Do not copy articles from this website.

ARTICLE CATEGORIES :
Agriculture Bioinformatics Applications Biotech Products Biotech Research
Biology Careers College/Edu DNA Environmental Biotech
Genetics Healthcare Industry News Issues Nanotechnology
Others Stem Cells Press Release Toxicology  


  |   Disclaimer/Privacy/TOS   |   Submission Guidelines   |   Contact Us