RNA is known to harbor more than 100 distinct types of post-transcriptional modifications, which can modulate its splicing, localization, stability and translation. It was found that methylation at the N6 position of adenosine (m6A) in mRNA is involved in the epigenetic control of gene expression. Recent transcriptome-wide mapping also revealed the presence of m1A, pseudouridine, N7-methylguanosine, and 2¢-O-methylated nucleosides in mRNA. We reason that a more complete understanding of the roles of these RNA modifications in epitranscriptomics requires a better understanding about how the reader, writer, and eraser proteins are regulated, and how these RNA modifications modulate cell signaling. In this presentation, I will discuss our recent development of a parallel-reaction monitoring (PRM)-based quantitative proteomic strategy for monitoring the levels of expression of reader, writer, and eraser proteins of RNA epitranscriptomic marks, and the application of this method for assessing how exposure to toxic chemicals modulates the expression levels of these epitranscriptomic modifiers. In addition, the application of the method for profiling how these epitranscriptomics modifiers are altered during metastatic transformation of cancer will also be described. Moreover, I will discuss our investigation about how changes in expression levels of METTL3, the catalytic component of the methyltransferase for m6A formation, and m6A demethylating enzymes, including FTO and ALKBH5 alter the expression levels of small GTPases and kinases. The method allowed for a systematic discovery of small GTPases and kinases that are under m6A-mediated epitranscriptomic regulation. Together, our quantitative proteomic approaches allowed for comprehensive assessments about how exposure to toxic chemicals alters epitranscriptomic modifiers and about the systematic discovery of small GTPases and kinases that are under m6A-mediated epitranscriptomic control.

Targeted quantitative proteomic approaches toward understanding epitranscriptomic regulations

2019 Fall National Meeting

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