Biology subjects

Sendinc, E.

Publications and source records attributed to Sendinc, E..

3 recordsLinked to original sources

bioRxiv2024

Mapping multiple RNA modifications simultaneously by proximity barcode sequencing

RNA is subject to a multitude of different chemical modifications that collectively represent the epitranscriptome. Individual RNA modifications including N6-methyladenosine (m6A) on mRNA play essential roles in the posttranscriptional control of gene expression. Recent technological advances have enabled the transcriptome-wide mapping of certain RNA modifications, to reveal their broad relevance and characteristic distribution patterns. However, convenient methods that enable the simultaneous mapping of multiple different RNA marks within the same sample are generally lacking. Here we present EpiPlex RNA modification profiling, a bead-based proximity barcoding assay with sequencing readout that expands the scope of molecular recognition-based RNA modification detection to multiple targets, while providing relative quantification and enabling low RNA input. Measuring signal intensity against spike-in controls provides relative quantification, indicative of the RNA mod abundance at each locus. We report on changes in the modification status of HEK293T cells upon treatment with pharmacological inhibitors separately targeting METTL3, the dominant m6A writer enzyme, and the EIF4A3 component of the exon junction complex (EJC). The treatments resulted in decreased or increased m6A levels, respectively, without effect on inosine levels. Inhibiting the helicase activity of EIF4A3 and EIF4A3 knockdown both cause a significant increase of m6A sites near exon junctions, consistent with the previously reported role of EIF4A3 in shaping the m6A landscape. Thus, EpiPlex offers a reliable and convenient method for simultaneous mapping of multiple RNA modifications to facilitate epitranscriptome studies.

genomics↗

bioRxiv2022

Selective Regulation of Tuft Cell-Like Small Cell Lung Cancer by Novel Transcriptional Co-activators C11orf53 and COLCA2

The DepMap project has generated a huge resource for investigating selectively essential genes, which represent potential cancer therapeutic targets. However, manually sorting out which of the hundreds of selectively essential genes is understudied and warrants investigations is time-consuming and probably not practical. To efficiently identify uncharacterized, selectively essential genes, we collected and ranked the 347 selectively essential genes from the DepMap dataset by their PubMed publication counts, based on the assumption that genes with low publication counts are un-studied or under-studied. We successfully validated two of the top candidates in our ranking system, C11orf53 and COLCA2, as new vulnerabilities that are selectively essential in the class II POU domain transcription factor POU2F3-dependent tuft cell-like small cell lung cancer (SCLC) cell lines. Importantly, we found that the sequence motif, which mediates physical interactions of the transcriptional co-activator POU2AF1 with two of the class II POU domain-containing family of transcription factors (POU2F1 and POU2F2), is also present in the N-terminal regions of C11orf53 and COLCA2. We further confirmed that 1) COLCA2 physically interacts with POU2F3 through this conserved sequence motif; 2) this interaction is important for COLCA2 to regulate tuft cell-like SCLC cell growth, and 3) both C11orf53 and COLCA2 contain transcriptional co-activator domains. Consistently, we find similar transcriptomic changes in response to the loss of COLCA2 or POU2F3 in SCLC cells. In summary, our analysis pipeline enables identification and prioritization of understudied but important, selectively essential genes, leading to the identification of two new transcriptional co-activators for the class II POU domain transcription factors. Disruption of this important physical interaction is predicted to be a potential therapeutic strategy to selectively inhibit tuft cell-like SCLCs.

molecular biology↗

bioRxiv2018

PCIF1 catalyzes m6Am mRNA methylation to regulate gene expression

mRNA modifications play an important role in regulating gene expression. One of the most abundant mRNA modifications is N6,2-O-dimethyladenosine (m6Am). Here, we demonstrate that m6Am is an evolutionarily conserved mRNA modification mediated by the Phosphorylated CTD Interacting Factor 1 (PCIF1), which catalyzes m6A methylation on 2-O-methylated adenine located at the 5 ends of mRNAs. Furthermore, PCIF1 catalyzes only 5 m6Am methylation of capped mRNAs, but not internal m6A methylation in vitro and in vivo. Our global mRNA methylation analysis revealed that there is no crosstalk between m6Am and m6A mRNA methylation events, suggesting that m6Am is functionally distinct from m6A. Importantly, our data indicate that m6Am negatively impacts translation of methylated mRNAs by antagonizing cap binding protein eIF4E. Together, we identify the first and only human mRNA m6Am methyltransferase and demonstrate a novel mechanism of gene expression regulation through PCIF1-mediated m6Am mRNA methylation in eukaryotes.\n\nHighlightsO_LIPCIF1 is an evolutionarily conserved mRNA m6Am methyltransferase\nC_LIO_LILoss of PCIF1 leads to a complete loss of m6Am, whereas m6A level and distribution are not affected\nC_LIO_LIPCIF1 mediated m6Am does not affect RNA Pol II transcription or mRNA stability\nC_LIO_LIm6Am-Exo-Seq is a robust methodology that enables global m6Am mapping\nC_LIO_LIm6Am suppresses cap dependent translation\nC_LI

molecular biology↗