Promoter identification and analysis of key glycosphingolipid biosynthesis-globo series pathway genes in piglets.

Glycosphingolipid biosynthesis-globo series pathway genes (FUT1, FUT2, ST3GAL1, HEXA, HEXB, B3GALNT1, and NAGA) play an important regulatory role in the defense against Escherichia coli F18 in piglets. In this study, we identified the transcription initiation site and promoter of this gene cluster by mined previous RNA-seq results using bioinformatics tools. The FUT1 transcription initiation region included five alternative splicing sites and two promoter regions, whereas each of the six other genes had one promoter. Dual luciferase reporter results revealed significantly higher transcriptional activity by FUT1 promoter 2, indicating that it played a more important role in transcription. The promoters of glycosphingolipid biosynthesis genes identified contained a CpG island within the first 500 bp, except for the B3GALNT1 promoter which included fewer CpG sites. These results provide a deeper insight into methylation and the regulatory mechanisms of glycosphingolipid biosynthesis-globo series pathway genes in piglets.

Developmental expression of LTßR and differential expression in Escherichia coli F18 resistant/sensitive piglets.

We analyzed LTßR mRNA expression in piglets from birth to weaning and compared the differential expression between Escherichia coli F18-resistant and sensitive populations to determine whether this gene could be used as a genetic marker for E. coli F18 resistance. Sutai piglets of different age groups (8, 18, 30, and 35 days; N = 4 each) and piglets demonstrating resistance/sensitivity to E. coli F18 were used. LTßR expression levels were determined by real-time PCR. The LTßR expression levels in the lymph node, duodenum, and jejunum were significantly higher in 8-day-old piglets than in the other age groups (P < 0.01), and the expression levels were significantly higher in the lungs of 8-day-old piglets than in 35-day-old piglets (P < 0.01) and 30 day-old piglets (P < 0.05). In liver tissue, the expression level was significantly higher in the 35-day-old piglets than in other age groups (P < 0.01). In the stomach tissue, the expression level was significantly higher in 35-day-old piglets than in 18-day-old piglets (P < 0.05). LTßR expression in the lymph nodes was significantly higher in the resistant group than in the sensitive group (P < 0.01), but there was no significant difference in the other tissues (P > 0.05). These results indicate that 8 days after birth is a crucial stage in the formation of mesentery lymph nodes and immune barriers in pigs, and increased expression of LTßR may be beneficial for developing resistance to E. coli F18.

Differential expression of FUT1 and FUT2 in Large White, Meishan, and Sutai porcine breeds.

To assess the relationship between the expression of a(1,2)-fucosyltransferase (FUT1 and FUT2) genes and resistance to Escherichia coli F18 in weaned pigs, FUT1 and FUT2 expression levels in Large White, Meishan, and Sutai pigs (with resistance to E. coli F18) were determined using real-time PCR. The results revealed that FUT1 and FUT2 expression levels were higher in the liver, lungs, kidneys, stomach, duodenum, and jejunum than in the muscle and heart. Medium FUT2 expression levels were detected in the spleen, thymus, and lymph nodes. Intestinal FUT1 expression levels were higher in Sutai pigs than in Large White and Meishan pigs (P < 0.05). However, intestinal FUT2 expression levels were lower in Sutai pigs than in Large White and Meishan pigs (P < 0.05). FUT1 and FUT2 expression levels did not differ between Large White and Meishan pigs (P > 0.05). The results revealed that high FUT1 expression levels and low FUT2 expression levels in the intestines of Sutai pigs affected FUT1 and FUT2 enzymes, the synthesis of type 2 H and type 1 H antigens, and E. coli F18 adhesion. Moreover, low FUT2 expression levels conferred resistance to E. coli F18.