The Study of RNA m5C writer NSUN5 regulation in human gliomas

Abstract

Background. Astrocytoma is a tumor of the human brain-derived from astrocytic-like glial cells. The disease is associated with poor patient prognosis and short survival. The improvement of early diagnostics of the disease by incorporating novel molecular markers emerging at the early stages of tumor development would contribute to improving the outcome of the disease. Epitranscriptome is a recently studied element of post-transcriptional regulation of gene expression. It includes a multitude of RNA modifications, most of which biological functions are still unclear. Epitranscriptome processes also involve hundreds of proteins and microRNA molecules that regulate the attachment, removal, and recognition of these modifications. One of the most frequent and relevant RNA modification is C5-methylation of cytosine (m5C), which was shown to have an important role in gene regulation. The modification can be carried out by few proteins called writers, however, the most common writer of m5C is RNA methyltransferase NSUN5. Recently few pilot studies revealed that NSUN5 might be involved in glioma development nevertheless, there is a lack of information about NSUN5 level regulation in gliomas. Thus, the AIM of the study was to elucidate if RNA 5mC mark writer NSUN5 is controlled by gene promoter methylation and/or via miRNA interference in human gliomas. Methods. In total 55 astrocytomas of grade II-IV were used for the study. Gene expression of NSUN5 was analyzed by quantitative RT-PCR using SYBR-green. TaqMan assay applied for microRNA level measurement, and MS-PCR used for NUSN5 promoter methylation analysis. Expression was calculated applying dCT method. RNA m5C modification in total RNA was measured applying “EpiQuik™ m6A RNA Methylation Quantification Kit”. Results. The study results did not reveal a significant connection between NSUN5 promoter methylation and NSUN5 gene expression in astrocytoma specimens, [...].