Adarb1, also known as ADAR2, is an adenosine-to-inosine (A-to-I) RNA-editing enzyme. RNA editing is a crucial post-transcriptional modification process that can affect the function of RNA molecules, influencing various biological processes such as gene expression regulation [4,5,6].

In Adarb1-knockout mice, rhythms of large populations of mRNA were attenuated, indicating its profound impact on RNA rhythms. These mice also exhibited short-period rhythms in locomotor activity and gene expression, associated with abnormal accumulation of CRY2, suggesting its role in the circadian clockwork [4]. In humans, bi-allelic variants in ADARB1 are associated with microcephaly, intellectual disability, and seizures, as these variants lead to reduced editing activity on known ADAR2 substrates [5]. Downregulated ADARB1 has been found to be involved in promoting cell metastasis in lung adenocarcinoma and ovarian cancer, and is related to shorter survival times in these cancer patients. In contrast, in glioblastoma, ADARB1 is upregulated and is involved in AKT-mediated temozolomide resistance [1,2,3].

In conclusion, Adarb1 is an essential RNA-editing enzyme that plays a significant role in biological processes such as the circadian rhythm. Its dysregulation is associated with various diseases, including cancers and neurodevelopmental disorders. The study of Adarb1-knockout mouse models has provided valuable insights into its functions in these disease-related processes, helping us to better understand the underlying mechanisms and potentially develop new therapeutic strategies.