Nicn1, also known as nicolin 1 gene, encodes a 213-amino-acid, 24 kDa nuclear protein [2]. It is mammalian-specific and consists of six exons spanning about 6 kb of genomic DNA [2]. The gene is expressed in a tissue-specific manner, with high expression in brain, testis, liver, and kidney [2]. Although its exact function remains to be fully elucidated, eQTL analysis shows associations between Nicn1 and SNPs in subcutaneous and visceral adipose tissues, and it is involved in biological pathways such as cortisol synthesis, thyroid hormone synthesis, and insulin secretion, which are related to obesity-associated sedentary behaviors [1].

In addition, Nicn1 has been identified as a host gene promoting HIV-1 latency. shRNA knockdown of Nicn1 significantly enhances HIV expression in primary CD4 T cells, suggesting that downregulation of Nicn1 stimulates RNA Polymerase II-mediated transcription of HIV-1 [3]. Also, in lung cancer studies, Nicn1 shows a strong correlation with FHIT expression in both LUAD and LUSC, indicating its potential role in lung cancer-related gene regulatory networks [4].

In conclusion, Nicn1 is a mammalian-specific gene with tissue-specific expression. Its involvement in multiple biological pathways related to obesity-associated sedentary behaviors, as well as its role in promoting HIV-1 latency and in lung cancer-related gene regulation, highlights its importance in various physiological and disease-related processes. Research on Nicn1 using genetic models can potentially provide further insights into these biological functions and disease mechanisms.