HnRNPA1 Specifically Recognizes the Base of Nucleotide at the Loop of RNA G-Quadruplex.

Xiao Liu,Yan Xu

doi:10.3390/molecules23010237

Abstract

Human telomere RNA performs various cellular functions, such as telomere length regulation, heterochromatin formation, and end protection. We recently demonstrated that the loops in the RNA G-quadruplex are important in the interaction of telomere RNA with heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1). Here, we report on a detailed analysis of hnRNPA1 binding to telomere RNA G-quadruplexes with a group of loop variants using an electrophoretic mobility shift assay (EMSA) and circular dichroism (CD) spectroscopy. We found that the hnRNPA1 binds to RNA G-quadruplexes with the 2’-O-methyl and DNA loops, but fails to bind with the abasic RNA and DNA loops. These results suggested that hnRNPA1 binds to the loop of the RNA G-quadruplex by recognizing the base of the loop’s nucleotides. The observation provides the first evidence that the base of the loop’s nucleotides is a key factor for hnRNPA1 specifically recognizing the RNA G-quadruplex.

Highlights

Human telomeric RNA has been reported to form G-quadruplex structures [1,2,3,4,5,6,7,8,9,10]
A previous study has suggested that telomere RNA and heterogeneous nuclear ribonucleoprotein A1 act together to facilitate telomere capping [12]
Our recent study has demonstrated that the loops present in the telomere RNA G-quadruplex are required for its binding to heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) [13]

Summary

Introduction

Human telomeric RNA has been reported to form G-quadruplex structures [1,2,3,4,5,6,7,8,9,10]. Our recent study has demonstrated that the loops present in the telomere RNA G-quadruplex are required for its binding to hnRNPA1 [13]. We have found that the base at the loop of the RNA G-quadruplex plays a key role in the binding of hnRNPA1 to the RNA G-quadruplex.

Results

Conclusion