Haplotype combination of the bovine INSIG1 gene sequence variants and association with growth traits in Nanyang cattle

RNA-Seq based transcriptome analysis during bovine viral diarrhoea virus (BVDV) infection

BACKGROUND

Bovine viral diarrhoea virus (BVDV) is the member of the genus Pestivirus within the Flaviviridae family and responsible for severe economic losses in the cattle industry. BVDV can employ 'infect-and-persist' strategy and 'hit-and-run' strategy to remain associated with hosts and thus contributes to BVDV circulation in cattle herds. BVDV have also evolved various strategies to evade the innate immunity of host. To further understand the mechanisms by which BVDV overcomes the host cell innate immune response and provide more clues for further understanding the BVDV-host interaction, in this descriptive study, we conducted a investigation of differentially expressed genes (DEGs) of the host during BVDV infection by RNA-Seq analysis.

RESULTS

Our analysis identified 1297, 1732, 3072, and 1877 DEGs in the comparison groups mock vs. MDBK cells infected with BVDV post 2 h (MBV2h), mock vs. MBV6h, mock vs. MBV12h, and mock vs. MBV24h, respectively. The reproducibility and repeatability of the results were validated by RT-qPCR. Enrichment analyses of GO annotations and KEGG pathways revealed the host DEGs that are potentially induced by BVDV infection and may participate in BVDV-host interactions. Protein-protein interaction (PPI) network analyses identified the potential interactions among the DEGs. Our findings suggested that BVDV infection induced the upregulation of genes involved in lipid metabolism. The expression of genes that have antiviral roles, including ISG15, Mx1, OSA1Y, were found to be downregulated and are thus potentially associated with the inhibition of host innate immune system during BVDV infection. The expression levels of F3, C1R, KNG1, CLU, C3, FB, SERPINA5, SERPINE1, C1S, F2RL2, and C2, which belong to the complement and coagulation signalling cascades, were downregulated during BVDV infection, which suggested that the complement system might play a crucial role during BVDV infection.

CONCLUSION

In this descriptive study, our findings revealed the changes in the host transcriptome expression profile during BVDV infection and suggested that BVDV-infection induced altering the host's metabolic network, the inhibition of the expression of antiviral proteins and genes within the complement system might be contributed to BVDV proliferation. The above findings provided unique insights for further studies on the mechanisms underlying BVDV-host interactions.

Central Role of the PPARγ Gene Network in Coordinating Beef Cattle Intramuscular Adipogenesis in Response to Weaning Age and Nutrition

Adipogenic/lipogenic transcriptional networks regulating intramuscular fat deposition (IMF) in response to weaning age and dietary starch level were studied. The longissimus muscle (LM) of beef steers on an early weaning (141 days age) plus high-starch diet (EWS) or a normal weaning (NW, 222 days age) plus starch creep-feed diet (CFS) was biopsied at 0 (EW), 25, 50, 96 (NW), 167, and 222 (pre-slaughter) days. Expression patterns of 35 target genes were studied. From NW through slaughter, all steers received the same high-starch diet. In EWS steers the expression of PPARG, other adipogenic (CEBPA, ZFP423) and lipogenic (THRSP, SREBF1, INSIG1) activators, and several enzymes (FASN, SCD, ELOVL6, PCK1, DGAT2) that participate in the process of IMF increased gradually to a peak between 96 and 167 days on treatment. Steers in NW did not achieve similar expression levels even by 222 days on treatment, suggesting a blunted response even when fed a high-starch diet after weaning. High-starch feeding at an early age (EWS) triggers precocious and sustained adipogenesis, resulting in greater marbling.

Haplotype combination of polymorphisms in the ADIPOQ gene promoter is associated with growth traits in Qinchuan cattle

Adiponectin modulates lipid and glucose metabolism in adipose tissues and is also related to bone metabolism. Polymorphisms in the ADIPOQ gene likely have an impact on growth traits in cattle. In this study, we examined the relationship between ADIPOQ polymorphisms and body measurement parameters in Chinese beef cattle. First, we sequenced ADIPOQ and 1.2 kb of DNA upstream of its promoter, and we found 14 polymorphisms. With the luciferase reporter assay, we showed that the two polymorphisms SNP PR_-135 A>G and PR_-68 G>C, which are located in the core region of promoter, influence promoter activity of ADIPOQ. Second, we identified three haplotypes involved in these two polymorphic sites: A (A-135/C-68), B (A-135/G-68), and C (G-135/G-68). Haplotypes B and C are major haplotypes in five Chinese populations of cattle (Qinchuan, Nanyang, Jiaxian, Hazakh, and Chinese Holstein). We studied the effects of these three haplotypes on body measurements, gene expression, and promoter activity, and we found that the genotypes are associated with body measurement parameters in Qinchuan cattle. Individuals with genotype BC (AG/GG) had significantly higher body height and heart girth than others, and this result may be interpreted by the following two observations. The promoter activity with haplotype B (A/G) is significantly higher than those with A (A/C) and C (G/G) in driving reporter gene transcription; the ADIPOQ mRNA level in cattle with genotype BC (AG/GG) is relatively lower than that in cattle with genotype BB (AA/GG).