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

• Main Authors: Xiao Liu, Yan Xu
• Format: Article
• Language: English
• Published: MDPI AG 2018-01-01
• Series: Molecules
• Subjects: hnRNPA1; RNA G-quadruplex; telomere RNA; loop of RNA G-quadruplex; base
• Online Access: http://www.mdpi.com/1420-3049/23/1/237

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.