Characterization and functional significance of polymorphisms in porcine Toll-like receptor (TLR) 5 gene

Isolation and characterization of porcine PILRB gene and its alternative splicing variants

Paired immunoglobulin-like type 2 receptor (PILR)β regulates inflammatory responses to pathogen infection, and therefore plays an important role in host disease resistance/susceptibility. However porcine PILRβ remains poorly characterized. In this study, we obtained the cDNA (V1) of its encoding gene, PILRB, and three alternative splicing (AS) variants (V2-4). The complete coding sequence of V1 was 621 bp long encoding a polypeptide of 206 aa. Compared with V1, V2 and V3 were formed by exon-skipping in the 3'-untranslated region (UTR), while V4 was formed by alternative 3' splice site of exon 3, resulting in a premature termination codon, combined with exon skipping in the 3'-UTR. Expression profile analysis showed that all the isoforms were most abundant in the spleen, and V1 was strongly induced by poly(I:C). Furthermore, the transcription of V1 altered with the increasing age and differed between species. Exon skipping in the 3'-UTR of V2 and V3 down-regulated expression of the luciferase reporter gene, and hence presumably of the PILRB gene, while V4 was subjected to nonsense-mediated mRNA decay. Additionally, five novel splicing patterns were detected using the minigene approach, indicating complex AS of porcine PILRB. These results will help to reveal the role of PILRβ in the host immune response using pig models, and will facilitate the breeding of pigs resistant to viral diseases through molecular breeding methods.

SNPs in the Toll1 receptor of Litopenaeus vannamei are associated with immune response

Tolls and Toll-like receptors (TLRs) are important regulators in the innate immune system and their genetic variations usually affect the host's susceptibility/resistance to pathogen infections. In this study, we report on the single nucleotide polymorphisms (SNPs) of Toll1 in Litopenaeus vannamei (LvToll1) and how this is associated with immune response. PCR-DGGE analysis revealed genetic polymorphisms in LvToll1 at both the genomic DNA (gDNA) and cDNA levels. Using high-throughput sequencing, 223 SNPs were identified at the gDNA level, of which 145 were non-synonymous SNP (nsSNP), with 3 nsSNPs having frequency over 1%. On the other hand, 60 SNPs were identified at the cDNA level including 38 nsSNPs and 4 nsSNPs with frequency over 1%. Upon challenging shrimps with Streptococcus iniae, Vibrio parahaemolyticus and white spot syndrome virus (WSSV), LvToll1 was shown to generate 6, 4 and 4 novel bands, respectively when analyzed with PCR-DGGE. Sequencing analysis of these bands showed that they contained 6, 4 and 2 nsSNPs, respectively. Moreover, the nsSNP C1526T was detected in S. iniae-resistant but not in susceptible shrimps. Most significantly, the C1526T mutation could shorten the α-helix of the LRR domain and was predicted to affect the function of LvToll1, indicating that SNP C1526T might be associated with shrimp's resistance to pathogen infections. In sum, our findings here reveal that the genetic polymorphisms of Toll receptor are linked with the immune response to pathogen infections in L. vannamei.