Pig breeding opportunities to mitigate African Swine Fever losses: The genome analysis option brings warthogs into the picture of food security in China.

Understated and important:the final part of the article discussion.

Summary

African swine fever virus (ASFV) is a highly infectious disease of domestic pigs, with virulent isolates causing a rapidly fatal hemorrhagic fever. In contrast, the porcine species endogenous to Africa tolerate infection. The ability of the virus to persist in one host while killing another genetically related host implies that disease severity may be, in part, modulated by host genetic variation. To complement transcription profiling approaches to identify the underlying genetic variation in the host response to ASFV, we have taken a candidate gene approach based on known signaling pathways that interact with the virus-encoded immunomodulatory protein A238L. We report the sequencing of these genes from different pig species and the identification and initial in vitro characterization of polymorphic variation in RELA (p65; v-rel reticuloendotheliosis viral oncogene homolog A), the major component of the NF-κB transcription factor. Warthog RELA and domestic pig RELA differ at three amino acids. Transient cell transfection assays indicate that this variation is reflected in reduced NF-κB activity in vitro for warthog RELA but not for domestic pig RELA. Induction assays indicate that warthog RELA and domestic pig RELA are elevated essentially to the same extent. Finally, mutational studies indicate that the S531P site conveys the majority of the functional variation between warthog RELA and domestic pig RELA. We propose that the variation in RELA identified between the warthog and domestic pig has the potential to underlie the difference between tolerance and rapid death upon ASFV infection.

Species-specific variation in RELA underlies differences in NF-κB activity: a potential role in African swine fever pathogenesis.

 Palgrave CJ(1), Gilmour L, Lowden CS, Lillico SG, Mellencamp MA, Whitelaw CB. 

Author information: (1)Veterinary Pathology Unit, Division of Veterinary Clinical Sciences, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG, United Kingdom

J Virol. 2011 Jun;85(12):6008-14. doi: 10.1128/JVI.00331-11. Epub 2011 Mar 30.


UPDATE See also

• Efficient nonmeiotic allele introgression in livestock using custom endonucleases

Wenfang Tan, Daniel F. Carlson, Cheryl A. Lancto, John R. Garbe, Dennis A. Webster, Perry B. Hackett, and Scott C. Fahrenkrug

PNAS October 8, 2013 110 (41) 16526-16531; https://doi.org/10.1073/pnas.1310478110


Significance

Selective breeding has long been practiced to enrich for desirable DNA variation that influences livestock traits. We demonstrate that genetic variants can be directly introgressed into livestock genomes using a modified transcription activator-like effector nuclease system. The transient exposure of livestock cells to sequence-targeted editors stimulates homology-directed repair to levels that eliminate the need for transgene-dependent selection. Use of oligonucleotide template enables efficient single nucleotide changes to the genome and permits the transmission of both natural and novel DNA sequence variants into naïve livestock breeds and species. Gene editing offers a powerful method for accelerating the genetic improvement of livestock for food and also for developing swine as a resource for regenerative medicine and models of human disease.

Abstract

We have expanded the livestock gene editing toolbox to include transcription activator-like (TAL) effector nuclease (TALEN)- and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9-stimulated homology-directed repair (HDR) using plasmid, rAAV, and oligonucleotide templates. Toward the genetic dehorning of dairy cattle, we introgressed a bovine POLLED allele into horned bull fibroblasts. Single nucleotide alterations or small indels were introduced into 14 additional genes in pig, goat, and cattle fibroblasts using TALEN mRNA and oligonucleotide transfection with efficiencies of 10–50% in populations. Several of the chosen edits mimic naturally occurring performance-enhancing or disease- resistance alleles, including alteration of single base pairs. Up to 70% of the fibroblast colonies propagated without selection harbored the intended edits, of which more than one-half were homozygous. Edited fibroblasts were used to generate pigs with knockout alleles in the DAZL and APC genes to model infertility and colon cancer. Our methods enable unprecedented meiosis-free intraspecific and interspecific introgression of select alleles in livestock for agricultural and biomedical applications.