CD163 Exon 7 Editing in Pigs for PRRSv Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for preventing Porcine Reproductive and Respiratory Syndrome (PRRS) in pigs are ineffective due to genetic diversity within the virus, leading to significant economic losses and the need for herd depopulation, while existing vaccines fail to control the disease effectively.
Innovation Solution
Targeted editing of the CD163 gene in pigs using CRISPR-Cas9 technology to introduce a homozygous deletion in exon 7, specifically excising the scavenger receptor cysteine-rich domain 5 (SRCR5), conferring resistance to PRRSv through precise gene editing with improved specificity and reduced unintended edits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vaccines are used to prevent PRRS, then disease control is attempted, but genetic diversity within the virus causes vaccine failure
Solution Approach 1:
The invention extracts and removes the vulnerable CD163 receptor from the pig genome using CRISPR-Cas9 gene editing. By deleting exon 7 of the CD163 gene, the virus can no longer bind to and enter the cells, effectively removing the target that the virus needs to cause infection, thereby rendering viral genetic diversity irrelevant to vaccine effectiveness
Solution Approach 2:
The invention changes the genetic parameter of the CD163 receptor by introducing a homozygous deletion in exon 7. This parameter change creates a fundamentally altered cellular state where the virus cannot recognize or enter the cells, providing reliable protection against PRRS regardless of viral strain variations
2Reliability
If herd depopulation is used to eliminate PRRS, then the virus is eliminated from the herd, but significant economic loss occurs
Solution Approach 1:
The invention performs preliminary action by genetically editing pigs before they are exposed to the virus. By pre-conferring resistance through CD163 exon 7 deletion, the pigs are protected in advance, eliminating the need for reactive herd depopulation measures and preventing the economic losses associated with losing entire herds
Solution Approach 2:
The invention applies preliminary anti-action by creating pigs that are inherently resistant to PRRS through gene editing. This preemptive resistance prevents virus establishment in the herd, counteracting the need for extreme measures like herd depopulation and preserving both animal life and economic value
3Reliability
If CRISPR-Cas9 gene editing is used to target CD163, then PRRSv resistance is achieved, but off-target edits may occur
Solution Approach 1:
The invention replaces traditional mechanical or chemical gene targeting methods with the precision of CRISPR-Cas9 RNA-guided nucleases. The guide RNA provides molecular recognition that specifically binds to the target CD163 exon 7 sequence, enabling precise editing while minimizing off-target effects through complementary base pairing specificity
Solution Approach 2:
The invention uses guide RNA as an intermediary between the Cas9 nuclease and the target DNA sequence. This intermediary provides sequence-specific recognition through base pairing, directing the nuclease activity precisely to exon 7 of CD163 while preventing unwanted off-target edits through strict complementarity requirements
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves PRRSv resistance by reducing viral uptake, demonstrated by lower viral loads and absence of clinical symptoms in genetically edited pigs, enabling effective prevention without herd depopulation.
Implementation Method 1
Targeted editing of the CD163 gene in pigs using CRISPR-Cas9 technology to introduce a homozygous deletion in exon 7
Implementation Method 2
The guide sequences (including the PAM) are set forth in SEQ ID NOs: 249 and 256
Data Source
AI summary
The present disclosure relates methods and compositions useful for prevention of porcine reproductive and respiratory syndrome virus (PRRSv) in animals, including animals of the species Sus scrofa. The present teachings relate to swine wherein at least one allele of a CD163 gene has been inactivated, and to specific methods and nucleic acid sequences used in gene editing to inactivate the CD163 gene. Swine wherein both alleles of the CD163 gene are inactivated are resistant to porcine reproductive and respiratory syndrome virus (PRRSv). Elite lines comprising homozygous CD163 edited genes retain their superior properties.