Biomol Ther.  2019 Feb;27(2):201-209. 10.4062/biomolther.2018.157.

Isolation of MLL1 Inhibitory RNA Aptamers

• Ul-Haq A
• Jin ML
• Jeong KW
• Kim HM
• Chun KH

• KMID: 2442012
• DOI: http://doi.org/10.4062/biomolther.2018.157

Abstract

Mixed lineage leukemia proteins (MLL) are the key histone lysine methyltransferases that regulate expression of diverse genes. Aberrant activation of MLL promotes leukemia as well as solid tumors in humans, highlighting the urgent need for the development of an MLL inhibitor. We screened and isolated MLL1-binding ssRNAs using SELEX (Systemic Evolution of Ligands by Exponential enrichment) technology. When sequences in sub-libraries were obtained using next-generation sequencing (NGS), the most enriched aptamers"”APT1 and APT2"”represented about 30% and 26% of sub-library populations, respectively. Motif analysis of the top 50 sequences provided a highly conserved sequence: 5"²-A[A/C][C/G][G/U][U/A]ACAGAGGG[U/A]GG[A/C] GAGUGGGU-3"². APT1, APT2, and APT5 embracing this motif generated secondary structures with similar topological characteristics. We found that APT1 and APT2 have a good binding activity and the analysis using mutated aptamer variants showed that the site information in the central region was critical for binding. In vitro enzyme activity assay showed that APT1 and APT2 had MLL1 inhibitory activity. Three-dimensional structure prediction of APT1-MLL1 complex indicates multiple weak interactions formed between MLL1 SET domain and APT1. Our study confirmed that NGS-assisted SELEX is an efficient tool for aptamer screening and that aptamers could be useful in diagnosis and treatment of MLL1-mediated diseases.

Keyword

Aptamers; SELEX; MLL1; Next-generation sequencing; ssRNA

MeSH Terms

Aptamers, Nucleotide*
Conserved Sequence
Diagnosis
Histones
Humans
In Vitro Techniques
Leukemia
Ligands
Lysine
Mass Screening
Methyltransferases
Myeloid-Lymphoid Leukemia Protein
RNA*
Aptamers, Nucleotide
Histones
Ligands
Lysine
Methyltransferases
Myeloid-Lymphoid Leukemia Protein
RNA