The Functions of N6-Methyladenosine in Nuclear RNAs.

N6-methyladenosine (m6A) is one of the most common modifications in both eukaryotic and prokaryotic mRNAs. It has been experimentally confirmed that m6A methylation is involved in the regulation of stability and translation of various mRNAs. Until recently, the majority of m6A-related studies have been focused on the cytoplasmic functions of this modification. Here, we review new data on the role of m6A in several key biological processes taking place in the cell nucleus, such as transcription, chromatin organization, splicing, nuclear-cytoplasmic transport, and R-loop metabolism. Based on analysis of these data, we suggest that m6A methylation of nuclear RNAs is another level of gene expression regulation which, together with DNA methylation and histone modifications, controls chromatin structure and functioning in various biological contexts.

Analyzing the Effects of Single Nucleotide Polymorphisms on hnRNPA2/B1 Protein Stability and Function: Insights for Anticancer Therapeutic Design.

Heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2/B1) is a pivotal player in m6A recognition, RNA metabolism, and antiviral responses. In the context of cancer, overexpression of hnRNPA2/B1, abnormal RNA levels, and m6A depositions are evident. This study focuses on two significant nonsynonymous single nucleotide polymorphisms (nsSNPs) within hnRNPA2/B1, namely, F66L and E92K. Our structural analyses reveal decreased stability in these mutants, with E92K being predicted to undergo destabilizing post-translational methylation. Furthermore, our extensive analysis of 44,239 tumor samples from the COSMIC database uncovers that amino acid position 92 exhibits the second-highest mutation frequency within hnRNPA2/B1, particularly associated with breast and lung cancers. This experimental data aligns with our theoretical studies, highlighting the substantial impact of the nsSNP at position 92 on hnRNPA2/B1's stability and functionality. Given the critical role of pre-mRNA splicing, transcription, and translation regulation in cellular function, it is important to assess the impact of these nsSNPs on the stability and function of the hnRNPA2/B1 protein to design more efficient anticancer therapeutics.