Chrnb3, the cholinergic receptor nicotinic beta 3 subunit gene, is a key component of nicotinic acetylcholine receptors (nAChRs), which are ligand-gated ion channels. These receptors play crucial roles in the nervous system, and the pathways they are involved in include those related to neurotransmission. Chrnb3 is of significant biological importance, especially in the context of nicotine-related behaviors and certain neurological functions [1-10]. Genetic models, such as transgenic mouse lines, are valuable for studying its function.

Functional studies in mice have shown that the α6*-nAChRs, in which Chrnb3 is involved, located in the ventral tegmental area (VTA), are important in controlling nicotine self-administration. For example, when the α6 subunit is selectively re-expressed in the VTA of the α6(-/-) mouse by a lentiviral vector, the reinforcing property of nicotine is restored. Also, genetic knock-in strains with replacement of Leu with Ser in the 9' residue in the M2 domain of α6 produce nicotine-hypersensitive mice with enhanced dopamine release [1].

In conclusion, Chrnb3 is essential for the function of nAChRs, especially those in the VTA related to nicotine-induced behaviors. Mouse models, including gene-knockout and knock-in models, have revealed its role in nicotine dependence, and its association with other conditions such as Parkinson's disease, alcohol consumption, and psoriasis vulgaris severity [1,2,3,4]. These findings contribute to our understanding of the biological mechanisms underlying these diseases and potentially offer new directions for treatment.

References:

1. Wen, L, Yang, Z, Cui, W, Li, M D. 2016. Crucial roles of the CHRNB3-CHRNA6 gene cluster on chromosome 8 in nicotine dependence: update and subjects for future research. In Translational psychiatry, 6, e843. doi:10.1038/tp.2016.103. https://pubmed.ncbi.nlm.nih.gov/27327258/

2. Bar-Shira, Anat, Gana-Weisz, Mali, Gan-Or, Ziv, Giladi, Nir, Orr-Urtreger, Avi. 2014. CHRNB3 c.-57A>G functional promoter change affects Parkinson's disease and smoking. In Neurobiology of aging, 35, 2179.e1-6. doi:10.1016/j.neurobiolaging.2014.03.014. https://pubmed.ncbi.nlm.nih.gov/24731518/

3. Hoft, N R, Corley, R P, McQueen, M B, Menard, S, Ehringer, M A. 2009. SNPs in CHRNA6 and CHRNB3 are associated with alcohol consumption in a nationally representative sample. In Genes, brain, and behavior, 8, 631-7. doi:10.1111/j.1601-183X.2009.00495.x. https://pubmed.ncbi.nlm.nih.gov/19500157/

4. Zhu, Kun-Ju, Quan, Cheng, Zhang, Chi, Li, Ke-Shen, Fan, Yi-Ming. 2014. Combined effect between CHRNB3-CHRNA6 region gene variant (rs6474412) and smoking in psoriasis vulgaris severity. In Gene, 544, 123-7. doi:10.1016/j.gene.2014.04.070. https://pubmed.ncbi.nlm.nih.gov/24792900/