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Numerous recent studies suggest that cancer-specific splicing alteration is a critical contributor to the pathogenesis of cancer. RNA-binding protein with serine-rich domain 1, RNPS1, is an essential regulator of the splicing process.However, the defined role of RNPS1 in tumorigenesis still remains elusive. We report here that the expression of RNPS1 is higher in cervical carcinoma samples from The Cancer Genome Atlas (TCGA-cervical squamous cell carcinoma and endocervical adenocarcinoma) compared to the normal tissues. Consistently, the expression of RNPS1 was high in cervical cancer cells compared to a normal cell line. This study shows for the first time that RNPS1 promotes cell proliferation and colony-forming ability of cervical cancer cells. Importantly, RNPS1 positively regulates migration-invasion of cervical cancer cells. Intriguingly, depletion of RNPS1 increases the chemosensitivity against the chemotherapeutic drug doxorubicin in cervical cancer cells. Further, we characterized the genome-wide isoform switching stimulated by RNPS1 in cervical cancer cell. Mechanistically, RNA-sequencing analysis showed that RNPS1 regulates the generation of tumor-associated isoforms of key genes, particularly Rac1b, RhoA, MDM4, and WDR1, through alternative splicing.RNPS1 regulates the splicing of Rac1 pre-mRNA via a specific alternative splicing switch and promotes the formation of its tumorigenic splice variant, Rac1b. While the transcriptional regulation of RhoA has been well studied, the role of alternative splicing in RhoA upregulation in cancer cells is largely unknown. Here, we have shown that the knockdown of RNPS1 in cervical cancer cells leads to the skipping of exons encoding the RAS domain of RhoA, consequently causing decreased expression of RhoA. Collectively, we conclude that the gain of RNPS1 expression may be associated with tumor progression in cervical carcinoma. RNPS1-mediated alternative splicing favors an active Rac1b/ RhoA signaling axis that could contribute to cervical cancer cell invasion and

Sin3 associated protein 18 (SAP18) is an evolutionary conserved protein, originally discovered in a complex with the transcriptional regulatory protein, Sin3. Subsequent investigations revealed SAP18 as an integral splicing component of the exon junction complex (EJC)‐associated apoptosis‐and splicing‐associated protein (ASAP)/PNN‐RNPS1‐SAP18 (PSAP) complex. In association with Sin3, SAP18 contributes toward transcriptional repression of genes implicated in embryonic development, stress response, human immunodeficiency virus type 1 replication, and tumorigenesis. As a part of EJC, SAP18 mediates alternative splicing events and suppresses the cryptic splice sites present within flanking regions of exon–exon junctions. In this review, we provide a thorough discussion on SAP18, focussing on its conserved dual role in transcriptional regulation and messenger RNA splicing. Recent research on the involvement of SAP18 in the emergence of cancer and human disorders has also been highlighted. The potential of SAP18 as a therapeutic target is also discussed in these recent studies, particularly related to malignancies of the myeloid lineage.

No abstract

A central processing event in eukaryotic gene expression is splicing. Concurrent with splicing, the core-EJC proteins, eIF4A3 and RBM8A-MAGOH heterodimer are deposited 24 bases upstream of newly formed exon-exon junctions. One of the core-EJC proteins, MAGOH contains a paralog MAGOHB, and this paralog pair is conserved across vertebrates. Upon analysis of the splice variants of MAGOH-paralogs, we have found the presence of alternate protein isoforms which are also evolutionarily conserved. Further, comparison of the amino acid sequence of the principal and alternate protein isoforms has revealed absence of key amino acid residues in the alternate isoforms. The conservation of principal and alternate isoforms correlates to the importance of MAGOH and MAGOHB across vertebrates.