The Guanine Trap: RNA Guanine‐tract Recognition and Encaging by hnRNP F quasi‐RRM2

Abstract

RNA splicing, the process where mRNA exons are ligated together after the introns are cut out, is required for the production of mature mRNA. Exons are the regions of mRNA that are translated into protein, and introns are noncoding regions. Alternative splicing, the process where different combinations of exons can be ligated together to generate many mRNAs from one gene, accounts for protein diversity and affects over 90 percent of human genes. Alternative splicing regulation is important because many diseases can arise if it occurs improperly. A molecular machine called the spliceosome performs RNA splicing to ligate exons, and hnRNP F (heterogeneous nuclear ribonucleoprotein) influences the spliceosome's alternative splicing decisions. hnRNP F binds to guanine‐(G) rich sequences in mRNA targets, resulting in their alternative splicing. Modeling shows a ‘cage’ formed around three G residues, which explains why hnRNP F binds G‐rich sequences. Using 3D printing technology, the Valders SMART team (Students Modeling A Research Topic) modeled hnRNP F binding via arginine 116, phenylalanine 120, and tyrosine 180. Research suggests that too much hnRNP H, a close homologue of hnRNP F, plays a role in promoting brain cancer. Understanding how hnRNP F binds G‐rich RNA to cause alternative splicing may lead to the development of therapies for genetic diseases. Supported by grants from NIH‐SEPA and NIH‐CTSI