LATEST UPDATES » Vol 22, No 11, November 2018 – The Asian Cancer - War on liver cancer       » 2018 Nobel Prize in Physiology or Medicine winners       » Women more prone to selected chemotherapy side effects       » Tibetan fungus could help fight liver cancer       » Standards for TCM decoction to be applied globally       » RMB200 million donation to build Tsinghua University Biomedical Sciences Building      
"To edit or not?"- the dilemma around CRISPR.

What is CRISPR in brief?

Derived from archaea and bacteria, CRISPR/Cas9 system consists of an endonuclease Cas9, CRISPR RNA (crRNA) and the trans-activating crRNA (tracrRNA). These molecules could recognize a target sequence and assemble together to form ribonucleoprotein complex for mediating gene editing. When used as an editing tool, a single guide RNA is designed and used in place of the crRNA and tracrRNA, which serve to enhance the robustness and convenience of targeting.

Now, we are empowered to edit the genome of our offspring – to correct them from inheritable genetic diseases (i.e. Down’s syndrome) and if we like, add in one or a few of our desirable traits. This has been made easier with the power of the newly-discovered CRISPR technology. Like other genome editing tools that have long been challenged with bioethical concerns, CRISPR emergence has once again cast unseen anxiety, caution and yet anticipation in the future of translational therapeutics for human diseases. Here, I shall briefly summed up what are the factors involved in the CRISPR dilemma.

1. Unforseen challenges: Low success rate and off-target effects

In April this year, a group from Sun Yat-sen University in China was the first to attempt CRISPR-editing on human embryos [1]. The embryos used were non-viable to begin with, and so were selected for research. CRISPR/Cas9 tool was used to target the Human beta-globin gene (HBB) as a step towards correcting Beta-thalassaemia, a common blood disorder in China population and is potentially fatal. Despite their efforts, their work was largely unsuccessful. In their approach, a customized CRISPR/Cas enzyme complex specific to HBB gene was designed and injected into single-cell embryos to allow editing of several target regions of the HBB gene. However, only 52% of the embryos were edited by the enzyme complex and among them, only 25% (7 embryos) were successfully edited at the HBB gene [1, 2]. In addition, the group found uncontrollable off-targeting genetic modifications in these embryos, which may lead to harmful mutations and phenotypic changes. With these surprising findings, the group acknowledged that at this stage, CRISPR/Cas9 was too amateur for clinical applications. However, they remained undeterred and have come up with plans to resolve these technical challenges. Leading researchers have warned that such germline modifications are inheritable and may cause unpredictable harmful consequences to future generation [2].

2. An edge over other genome editing tools

i. Ease and Convenience

The CRISPR/Cas9 components can be applied to edit any gene as long as a guide RNA is designed accordingly to the target gene. This greatly simplifies the methodology of gene editing relative to other existing tools (i.e. TALEN and zinc-finger nucleases) which require the engineering of a guide protein. Moreover, questions on the specificity of CRISPR have driven studies to refine the functions and characteristics of Cas9 [3]. This would help ensure higher precision in target gene modification and to reduce off-target mutation.

ii. Versatile and Widely Applicable

Acting at the cellular level, CRISPR/Cas9 has also found its way into the biological system of monocots and dicot plants [4, 5], drosophila [6], mice [7], rats [8] as well as in higher mammals like pig and sheep [9]. Just to name a few of its vast applications, stronger resistance crops against fungal growth are under study by using CRISPR to target multiple copies of the plant gene [4, 5]. CRISPR-mediated knock-in mice with introduction of human genes to create humanized system can be used to study cancer, model Infectious diseases, correct blood disorders, as well as improve on antibiotic resistance [7]. By tweaking the Myostatin gene of pig embryos, pigs with double-muscled can be produced and this alternative offers more meat to the consumers [9].

By Editor: Shirley Lam

Click here for the complete issue.

news Asia is the fastest growing region for nutraceuticals
news 2018 Nobel Prize in Physiology or Medicine winners
news Vitafoods Asia expands by 40 per cent in 2018
Asia Pacific Biotech News

APBN Editorial Calendar 2018
Obesity / Outlook for 2018
Searching for the fountain of youth
Women in Science - Making a difference
Digestive health in the 21st century - Trust your guts
Dental health - The root to good health
Cancer - Therapies and strategies for better patient outcomes
Water management - Technologies for biotech and pharmaceutical industries
Regenerative technology - Meat of the future
Doctor Robot - The digital healthcare revolution
Bones / Breast cancer
Liver health / Top science research nations & institutions
AIDS / Breakthrough of the year/Emerging trends
Editorial calendar is subjected to changes.
About Us
Available issues
Editorial Board
Letters to Editor
Instructions to Authors
Advertise with Us
World Scientific Publishing Co. Pte. Ltd.
5 Toh Tuck Link, Singapore 596224
Tel: 65-6466-5775
Fax: 65-6467-7667
» For Editorial Enquiries:
   biotech_edit@wspc.com or Ms Lim Guan Yu
» For Subscriptions, Advertisements &
   Media Partnerships Enquiries:
Copyright© 2018 World Scientific Publishing Co Pte Ltd  •  Privacy Policy