Nat9, or N-acetyltransferase 9, is an important gene with diverse functions. It belongs to the N-acetyltransferase superfamily and is involved in various biological processes. For instance, it plays a role in host-virus interactions, immune-related processes, and may be associated with reproductive traits. It has been shown to be involved in pathways like N-terminal acetylation, which can affect protein degradation and function [2].

In pigs, the NAT9 gene is associated with litter size traits. Polymorphisms in this gene are significantly associated with the litter size of first parity in Large White and Landrace pig populations, suggesting it could be a candidate gene for increasing litter size in pigs [1]. In another study, in Berkshire pigs, the GG genotype of a NAT9 SNP had the highest values for litter size traits, and this genotype also expressed higher levels of NAT9 mRNA in the endometrium [3]. Regarding its role in virus-host interactions, Nat9 in pigs is an endoplasmic reticulum-resident N-acetyltransferase and a host restriction factor for Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) infection. It inhibits PRRSV proliferation in an acetyltransferase-activity-dependent manner by N-terminally acetylating the viral structural protein GP5, which promotes GP5 degradation and decreases virion assembly. However, PRRSV can inhibit the expression of Nat9 to support virion assembly [2]. Additionally, in mice, loss of Nat9 renders them more susceptible to viral infection as it is involved in protecting STAT2 from methionine oxidation through enhancing the enzymatic activity of MSRB2 upon IFN treatment [4].

In conclusion, Nat9 has essential functions in reproductive and antiviral processes. Studies in pigs and mice have revealed its significance in litter size and antiviral defense respectively. Understanding the role of Nat9 through these model-based research can provide insights into improving pig breeding and developing strategies against viral infections [1,2,3,4].

References:

1. Jiugang, Zhao, Jing, Lan, Yonggang, Liu. 2011. Characterization, expression profile, polymorphism and association of porcine NAT9 gene. In Molecular biology reports, 39, 3137-42. doi:10.1007/s11033-011-1079-5. https://pubmed.ncbi.nlm.nih.gov/21688147/

2. Li, Xiaoyang, Sun, Ruiqi, Guo, Yanyu, Li, Zexing, Huang, Jinhai. 2023. N-Acetyltransferase 9 Inhibits Porcine Reproductive and Respiratory Syndrome Virus Proliferation by N-Terminal Acetylation of the Structural Protein GP5. In Microbiology spectrum, 11, e0244222. doi:10.1128/spectrum.02442-22. https://pubmed.ncbi.nlm.nih.gov/36695606/

3. Hwang, Jung Hye, An, Sang Mi, Yu, Go Eun, Ha, Jeongim, Kim, Chul Wook. 2018. Association of single-nucleotide polymorphisms in NAT9 and MAP3K3 genes with litter size traits in Berkshire pigs. In Archives animal breeding, 61, 379-386. doi:10.5194/aab-61-379-2018. https://pubmed.ncbi.nlm.nih.gov/32175444/

4. Xue, Binbin, Li, Huiyi, Liu, Shun, Tang, Songqing, Zhu, Haizhen. . The redox cycling of STAT2 maintains innate immune homeostasis. In Cell reports, 40, 111215. doi:10.1016/j.celrep.2022.111215. https://pubmed.ncbi.nlm.nih.gov/35977519/