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Stojic, L.

Publications and source records attributed to Stojic, L..

4 recordsLinked to original sources

The RNA-binding protein RSRC2 promotes mitotic fidelity by interacting with the lncRNA C1QTNF1-AS1

Mitotic fidelity depends on proper chromosome alignment at the spindle equator, a process known as chromosome congression, driven by well-established protein networks. Whereas RNA-binding proteins and noncoding RNAs have been implicated in cell division, their interplay during this process remains unknown. Here, we discover that RSRC2, an arginine/serine-rich RNA-binding protein, plays an essential role in cell division by interacting with the long non-coding RNA C1QTNF1-AS1. The loss of either RSRC2 or C1QTNF1-AS1 results in defects in chromosome congression and mitotic progression. We show that RSRC2 interacts with distinct sets of proteins involved in splicing and centrosome biogenesis, contributing to the fidelity of cell division through two different mechanisms: one linked to the splicing of mitotic regulators and the other by localising to mitotic centrosomes for which the interaction with the C1QTNF1-AS1 RNA is required. Our study uncovers RSRC2 as a new regulator of cell division and illustrates how RNA-protein complexes promote error-free mitosis.

cell biology↗

TREX reveals proteins that bind to specific RNA regions in living cells

Different regions of RNA molecules can often engage in specific interactions with distinct RNA-binding proteins (RBPs), giving rise to diverse modalities of RNA regulation and function. However, there are currently no methods for unbiased identification of RBPs that interact with specific RNA regions in living cells under endogenous settings. Here, we introduce TREX (Targeted RNase H-mediated extraction of crosslinked RBPs), a highly sensitive approach for identifying proteins that directly bind to specific RNA regions in living cells. We demonstrate that TREX outperforms existing methods in identifying known interactors of U1 snRNA, and reveals endogenous region-specific interactors of NORAD lncRNA. Using TREX, we generated a comprehensive region-by-region interactome for 45S rRNA, uncovering both established and novel interactions that regulate ribosome biogenesis. With its applicability to any RNA in any cell-type, TREX is the first RNA-centric tool for unbiased positional mapping of endogenous RNA-protein interactions in living cells.

cell biology↗

A high-content RNAi screen reveals multiple roles for long noncoding RNAs in cell division

Genome stability relies on proper coordination of mitosis and cytokinesis, where dynamic microtubules capture and faithfully segregate chromosomes into daughter cells. The role of long noncoding RNAs (lncRNAs) in controlling these processes however remains largely unexplored. To identify lncRNAs with mitotic functions, we performed a high-content RNAi imaging screen targeting more than 2,000 human lncRNAs. By investigating major hallmarks of cell division such as chromosome segregation, mitotic duration and cytokinesis, we discovered numerous lncRNAs with functions in each of these processes. The chromatin-associated lncRNA, linc00899, was selected for in-depth studies due to the robust mitotic delay observed upon its depletion. Transcriptome analysis of linc00899-depleted cells together with gain-of-function and rescue experiments across multiple cell types identified the neuronal microtubule-binding protein, TPPP/p25, as a target of linc00899. Linc00899 binds the genomic locus of TPPP/p25 and suppresses its transcription through a cis-acting mechanism. In cells depleted of linc00899, the consequent upregulation of TPPP/p25 alters microtubule dynamics and is necessary and sufficient to delay mitosis. Overall, our comprehensive screen identified several lncRNAs with roles in genome stability and revealed a new lncRNA that controls microtubule behaviour with functional implications beyond cell division.

cell biology↗

Specificity of RNAi, LNA and CRISPRi as loss-of-function methods in transcriptional analysis

Loss-of-function (LOF) methods, such as RNA interference (RNAi), antisense oligonucleotides or CRISPR-based genome editing, provide unparalleled power for studying the biological function of genes of interest. When coupled with transcriptomic analyses, LOF methods allow researchers to dissect networks of transcriptional regulation. However, a major concern is nonspecific targeting, which involves depletion of transcripts other than those intended. The off-target effects of each of these common LOF methods have yet to be compared at the whole-transcriptome level. Here, we systematically and experimentally compared non-specific activity of RNAi, antisense oligonucleotides and CRISPR interference (CRISPRi). All three methods yielded non-negligible offtarget effects in gene expression, with CRISPRi exhibiting clonal variation in the transcriptional profile. As an illustrative example, we evaluated the performance of each method for deciphering the role of a long noncoding RNA (lncRNA) with unknown function. Although all LOF methods reduced expression of the candidate lncRNA, each method yielded different sets of differentially expressed genes upon knockdown as well as a different cellular phenotype. Therefore, to definitively confirm the functional role of a transcriptional regulator, we recommend the simultaneous use of at least two different LOF methods and the inclusion of multiple, specifically designed negative controls.

genomics↗