Project description:The project aims to identify the RNA binding proteins that can specifically bind to mRNA internal modification N7-methylguanosine (m7G). N7-methylguanosine (m7G) methylation has been long identified as the essential cap modification for eukaryotic mRNA, but later has been identified internally in various types of RNAs, including tRNA, rRNA, miRNA, and mRNA. While the METTL1/WDR4 complex, responsible for tRNA m7G installation, has been suggested to be responsible for internal mRNA modification as well, little is known about the proteins that can identify and interact with m7G. To better understand its interaction with RNA binding proteins and further define its regulatory function in mRNA metabolism, we performed the experiment to pulldown proteins with different binding affinity on unmodified G and m7G and subject the enriched fractions to mass spectrometry.
Project description:Identifying tertiary structures and protein binding sites on RNA molecules remains a key challenge in RNA biology. We report a new chemical probing strategy termed multi-site DMS-MaP (msDMS-MaP) that exploits base tautomerization during mutational profiling reverse-transcription to measure typically invisible DMS-induced modifications at the N7 position of G. These N7-G modifications are now resolved concurrently with conventional N1 and N3 modifications with only minor modifications to established protocols, providing a multi-dimensional, single-molecule readout of RNA structure. We show that N7-G reactivity specifically reports on RNA tertiary and quaternary structure, enabling identification of diverse, functionally significant motifs such as cooperatively folding tertiary domains and protein binding sites in living cells. We apply msDMS-MaP to obtain a map of the quaternary structural ensemble of the 7SK non-coding snRNP, revealing unique protein binding sites across three 7SK structural isoforms. msDMS-MaP represents a broadly applicable strategy for enhanced RNA functional motif discovery and characterization.
Project description:Identifying tertiary structures and protein binding sites on RNA molecules remains a key challenge in RNA biology. We report a new chemical probing strategy termed multi-site DMS-MaP (msDMS-MaP) that exploits base tautomerization during mutational profiling reverse-transcription to measure typically invisible DMS-induced modifications at the N7 position of G. These N7-G modifications are now resolved concurrently with conventional N1 and N3 modifications with only minor modifications to established protocols, providing a multi-dimensional, single-molecule readout of RNA structure. We show that N7-G reactivity specifically reports on RNA tertiary and quaternary structure, enabling identification of diverse, functionally significant motifs such as cooperatively folding tertiary domains and protein binding sites in living cells. We apply msDMS-MaP to obtain a map of the quaternary structural ensemble of the 7SK non-coding snRNP, revealing unique protein binding sites across three 7SK structural isoforms. msDMS-MaP represents a broadly applicable strategy for enhanced RNA functional motif discovery and characterization.