Asmt, short for N-acetylserotonin O-methyltransferase, is a key rate-limiting enzyme responsible for melatonin biosynthesis [1,2,3,4]. Melatonin is a crucial regulator of circadian and seasonal rhythms in animals, and thus, Asmt plays an essential role in maintaining these rhythms [4]. Genetic models, such as gene knockout mouse models, have been valuable in studying Asmt's functions.

In female Asmt-deficient (Asmtft/ft) mice, deletion of 20 bp of exon 2 of Asmt led to anxiety-and depression-like behaviors along with gut microbiota remodeling. These female mice also showed lower neurobehavioral adaptability to exercise compared to wild-type mice, indicating that Asmt in females maintains gut microbiota plasticity and enhances exercise-related neurobehavioral adaptability [1]. In another study, Asmt knockout in mice induced depression-like behaviors, which were alleviated by swimming exercise. Swimming also increased serum levels of melatonin and 5-hydroxytryptamine in these knockout mice [2].

In conclusion, Asmt is vital for maintaining circadian rhythms through its role in melatonin synthesis. Gene knockout mouse models have revealed its significance in behaviors related to depression and anxiety, as well as in the adaptability to exercise, suggesting its potential importance in understanding and treating related neuropsychiatric disorders.

References:

1. Liu, Weina, Huang, Zhuochun, Zhang, Ye, Zou, Yong, Qi, Zhengtang. 2023. ASMT determines gut microbiota and increases neurobehavioral adaptability to exercise in female mice. In Communications biology, 6, 1126. doi:10.1038/s42003-023-05520-8. https://pubmed.ncbi.nlm.nih.gov/37935873/

2. Liu, Wenbin, Huang, Zhuochun, Xia, Jie, Qi, Zhengtang, Liu, Weina. . Gene expression profile associated with Asmt knockout-induced depression-like behaviors and exercise effects in mouse hypothalamus. In Bioscience reports, 42, . doi:10.1042/BSR20220800. https://pubmed.ncbi.nlm.nih.gov/35771226/

3. Moskaleva, P V, Shnayder, N A, Nasyrova, R F. . [Association of polymorphic variants of DDC (AADC), AANAT and ASMT genes encoding enzymes for melatonin synthesis with the higher risk of neuropsychiatric disorders]. In Zhurnal nevrologii i psikhiatrii imeni S.S. Korsakova, 121, 151-157. doi:10.17116/jnevro2021121041151. https://pubmed.ncbi.nlm.nih.gov/34184492/

4. Teng, J, Wang, D, Wang, W, Zhang, Q, Tang, H. 2022. Transcriptional regulation of the chicken ASMT gene - a preliminary analysis. In British poultry science, 63, 833-839. doi:10.1080/00071668.2022.2090230. https://pubmed.ncbi.nlm.nih.gov/35702898/