Project description:Influenza A viruses (IAVs) mRNA splicing represents an essential step in the viral life cycle. Here, we show that induction of SRSF5 by IAVs promotes viral replication by enhancing M mRNA splicing. To determine the motif in the M pre-mRNA targeted by SRSF5 RRM2 domain, the RNA eluted from co-precipitation of SRSF5–Flag from IAV-infected srsf5−/− HEK293 cells was subjected to deep sequencing analysis.
Project description:SR proteins exhibit diverse functions ranging from their role in constitutive and alternative splicing, to virtually all aspects of mRNA metabolism. These findings have attracted growing interest in deciphering the regulatory mechanisms that control the tissue-specific expression of these SR proteins. In this study, we show that SRSF5 protein decreases drastically during erythroid cell differentiation, contrasting with a concomitant upregulation of SRSF5 mRNA level. Proteasome chemical inhibition provided strong evidence that endogenous SRSF5 protein, as well as protein deriving from stably transfected SRSF5 cDNA, are both targeted to proteolysis as the cells undergo terminal differentiation. Consistently, functional experiments show that overexpression of SRSF5 enhances a specific endogenous pre-mRNA splicing event in proliferating cells, but not in differentiating cells, due to proteasome-mediated targeting of both endogenous and transfection-derived SRSF5. Further investigation of the relationship between SRSF5 structure and its post-translation regulation and function, suggested that the RNA recognition motifs of SRSF5 are sufficient to activate pre-mRNA splicing, whereas proteasome-mediated proteolysis of SRSF5 requires the presence of the C-terminal RS domain of the protein. Phosphorylation of SR proteins is a key post-translation regulation that promotes their activity and subcellular availability. We here show that inhibition of the CDC2-like kinase (CLK) family and mutation of the AKT phosphorylation site Ser86 on SRSF5, have no effect on SRSF5 stability. We reasoned that at least AKT and CLK signaling pathways are not involved in proteasome-induced turnover of SRSF5 during late erythroid development.
Project description:L-Arginine promotes oral keratinocyte proliferation under high glucose conditions. The treatment leads to changes in a substantial number of gene transcripts related to cell cycle, cell proliferation, and spliceosome GO terms as well as signaling pathways. Among these top-upregulated genes, CYP1A1, SKP2, and SRSF5 are of particular significance.
Project description:We used HeLa cells expressing GFP-tagged SRSF5 and the rapid depletion plasmid hGRAD from genomic loci. SRSF5 depletion was started after addition of Doxycyclin and was allowed for 2h, 8h and 16h. One hour before harvesting, cells were incubated with 4-sU for exactly 1 hour to label newly transcribed RNAs. 4-sU-labelled RNAs were biotinylated and purified over streptavidin beads and transformed into an RNA-seq library. We compared differential expression and intron retention between T0 and the other time points.