The avian leukosis virus subgroup J (ALV-J) belongs to the chicken retrovirus that causes enormous economic losses in the poultry industry. Interferon-stimulated genes (ISGs) are critical for controlling virus infections. Here, we identified 897 type I ISGs induced by interferon-α (IFN-α) in chicken peripheral blood mononuclear cell (PBMC) by RNA-Seq. In addition, we further identified 152 potential anti-ALV-J chicken type I ISGs. Among these potential anti-ALV-J ISGs, chicken cholesterol 25-hydroxylase (chCH25H) was selected for further antiviral mechanism studies in chicken embryo fibroblast cell lines (DF1). The gene chCH25H is located on chromosome 6 and clustered in a distinct group with mammals CH25H in the phylogenetic tree. The core promoter region of chCH25H was located within −75/−1 sequence. We found that chCH25H was induced by chicken IFN-α and ALV-J in DF1 cells. The overexpression of chCH25H significantly inhibited ALV-J replication in DF1 cells at 48 h post infection (hpi). In addition, ALV-J replication was significantly enhanced in the chCH25H- knockout DF1 cells. Furthermore, we demonstrated that chCH25H restricted ALV-J infection through the production of 25-hydroxycholesterol (25HC), rather than type I and II interferon. Our results identified 152 potential anti-ALV-J chicken type I ISGs and revealed that 25HC, the product of chCH25H, could be used as a natural antiviral agent to control ALV-J infection.

Background: Myoblast differentiation requires metabolic reprogramming driven by increased mitochondrial biogenesis and oxidative phosphorylation. The canonical GH-GHR-IGFs axis in liver exhibits a great complexity in response to somatic growth. However, the underlying mechanism of whether local GHR acts as a control valve to regulate mitochondrial function through mitochondrial biogenesis during myoblast differentiation remains unknown. Methods: We manipulated the GHR expression in chicken primary myoblast to investigate its roles in mitochondrial biogenesis and function during myoblast differentiation. Results: We reported that GHR is induced during myoblast differentiation. Local GHR promoted mitochondrial biogenesis during myoblast differentiation, as determined by the fluorescence intensity of Mito-Tracker Green staining and MitoTimer reporter system, the expression of mitochondrial biogenesis markers (PGC1α, NRF1, TFAM) and mtDNA encoded gene (ND1, CYTB, COX1, ATP6), as well as mtDNA content. Consistently, local GHR enhanced mitochondrial function during myoblast differentiation, as determined by the oxygen consumption rate, mitochondrial membrane potential, ATP level and ROS production. We next revealed that the regulation of mitochondrial biogenesis and function by GHR depends on IGF1. In terms of the underlying mechanism, we demonstrated that IGF1 regulates mitochondrial biogenesis via PI3K/AKT/CREB pathway. Additionally, GHR knockdown repressed myoblast differentiation. Conclusions: In conclusion, our data corroborate that local GHR acts as a control valve to enhance mitochondrial function by promoting mitochondrial biogenesis via IGF1-PI3K/AKT/CREB pathway during myoblast differentiation.

Golgin subfamily B member 1 (GOLGB1) gene encodes the coat protein 1 vesicle inhibiting factor, giantin. Previous study showed that mutations of the GOLGB1 gene are associated with dozens of human developmental disorders and diseases. However, the biological function of GOLGB1 gene in chicken is still unclear. In this study, we detected a novel 65-bp insertion/deletion (indel) polymorphism in the chicken GOLGB1 intron 5. Association of this indel with chicken growth and carcass traits was analyzed in a yellow chicken population. Results showed that this 65-bp indel was significantly associated with chicken body weight (p < 0.05), highly significantly associated with neck weight, abdominal fat weight, abdominal fat percentage and the yellow index b of breast (p < 0.01). Analysis of genetic parameters indicated that “I” was the predominant allele. Except for the yellow index b of breast, II genotype individuals had the best growth characteristics, by comparison with the ID genotype and DD genotype individuals. Moreover, the mRNA expression of GOLGB1 was detected in the liver tissue of chicken with different GOLGB1 genotypes, where the DD genotype displayed high expression levels. These findings hinted that the 65-bp indel in GOLGB1 could be assigned to a molecular marker in chicken breeding and enhance production in the chicken industry.