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Otalora K, Riera JL, Tavecchia G, Rotger A, Igual JM, Trotta JP, Baldo L. Population genetics and phylogeographic history of the insular lizard Podarcis lilfordi (Gunther, 1874) from the Balearic Islands based on genome-wide polymorphic data. Ecol Evol 2024; 14:e11407. [PMID: 38799398 PMCID: PMC11116764 DOI: 10.1002/ece3.11407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/12/2024] [Accepted: 04/30/2024] [Indexed: 05/29/2024] Open
Abstract
Islands provide a great system to explore the processes that maintain genetic diversity and promote local adaptation. We explored the genomic diversity of the Balearic lizard Podarcis lilfordi, an endemic species characterized by numerous small insular populations with large phenotypic diversity. Using the newly available genome for this species, we characterized more than 300,000 SNPs, merging genotyping-by-sequencing (GBS) data with previously published restriction site-associated DNA sequencing (RAD-Seq) data, providing a dataset of 16 island populations (191 individuals) across the range of species distribution (Menorca, Mallorca, and Cabrera). Results indicate that each islet hosts a well-differentiated population (F ST = 0.247 ± 0.09), with no recent immigration/translocation events. Contrary to expectations, most populations harbor a considerable genetic diversity (mean nucleotide diversity, P i = 0.144 ± 0.021), characterized by overall low inbreeding values (F IS < 0.1). While the genetic diversity significantly decreased with decreasing islet surface, maintenance of substantial genetic diversity even in tiny islets suggests variable selection or other mechanisms that buffer genetic drift. Maximum-likelihood tree based on concatenated SNP data confirmed the existence of the two major independent lineages of Menorca and Mallorca/Cabrera. Multiple lines of evidence, including admixture and root testing, robustly placed the origin of the species in the Mallorca Island, rather than in Menorca. Outlier analysis mainly retrieved a strong signature of genome differentiation between the two major archipelagos, especially in the sexual chromosome Z. A set of proteins were target of multiple outliers and primarily associated with binding and catalytic activity, providing interesting candidates for future selection studies. This study provides the framework to explore crucial aspects of the genetic basis of phenotypic divergence and insular adaptation.
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Affiliation(s)
- Katherin Otalora
- Department of Evolutionary Biology, Ecology and Environmental Sciences, Biology FacultyUniversity of Barcelona (UB)BarcelonaSpain
- Fundación FUNMAJO, EBA, RAIEC, Biodiversity BranchTunjaBoyacáColombia
| | - Joan Lluís Riera
- Department of Evolutionary Biology, Ecology and Environmental Sciences, Biology FacultyUniversity of Barcelona (UB)BarcelonaSpain
| | - Giacomo Tavecchia
- Animal Demography and Ecology Unit (GEDA‐IMEDEA, CSIC‐UIB)EsporlesSpain
| | - Andreu Rotger
- Animal Demography and Ecology Unit (GEDA‐IMEDEA, CSIC‐UIB)EsporlesSpain
| | - José Manuel Igual
- Animal Demography and Ecology Unit (GEDA‐IMEDEA, CSIC‐UIB)EsporlesSpain
| | - Jean‐Remi Paul Trotta
- CNAG‐CRG, Centre for Genomic Regulation (CRG)Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
| | - Laura Baldo
- Department of Evolutionary Biology, Ecology and Environmental Sciences, Biology FacultyUniversity of Barcelona (UB)BarcelonaSpain
- Institute for Research on Biodiversity (IRBio)University of Barcelona (UB)BarcelonaSpain
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Qin Z, Yang J, Zhang K, Gao X, Ran Q, Xu Y, Wang Z, Lou D, Huang C, Zellmer L, Meng G, Chen N, Ma H, Wang Z, Liao DJ. Updating mRNA variants of the human RSK4 gene and their expression in different stressed situations. Heliyon 2024; 10:e27475. [PMID: 38560189 PMCID: PMC10980951 DOI: 10.1016/j.heliyon.2024.e27475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 02/11/2024] [Accepted: 02/29/2024] [Indexed: 04/04/2024] Open
Abstract
We determined RNA spectrum of the human RSK4 (hRSK4) gene (also called RPS6KA6) and identified 29 novel mRNA variants derived from alternative splicing, which, plus the NCBI-documented ones and the five we reported previously, totaled 50 hRSK4 RNAs that, by our bioinformatics analyses, encode 35 hRSK4 protein isoforms of 35-762 amino acids. Many of the mRNAs are bicistronic or tricistronic for hRSK4. The NCBI-normalized NM_014496.5 and the protein it encodes are designated herein as the Wt-1 mRNA and protein, respectively, whereas the NM_001330512.1 and the long protein it encodes are designated as the Wt-2 mRNA and protein, respectively. Many of the mRNA variants responded differently to different situations of stress, including serum starvation, a febrile temperature, treatment with ethanol or ethanol-extracted clove buds (an herbal medicine), whereas the same stressed situation often caused quite different alterations among different mRNA variants in different cell lines. Mosifloxacin, an antibiotics and also a functional inhibitor of hRSK4, could inhibit the expression of certain hRSK4 mRNA variants. The hRSK4 gene likely uses alternative splicing as a handy tool to adapt to different stressed situations, and the mRNA and protein multiplicities may partly explain the incongruous literature on its expression and comports.
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Affiliation(s)
- Zhenwei Qin
- Section of Forensic Science and Pathology, School of Basic Medical Sciences, Guizhou University of Traditional Chinese Medicine, Dong-Qing-Nan Road, Guiyang, 550025, Guizhou Province, China
| | - Jianglin Yang
- Center for Clinical Laboratories, The Affiliated Hospital of Guizhou Medical University, 4 Beijing Rd, Guiyang, 550004, Guizhou Province, China
- Key Lab of Endemic and Ethnic Diseases of the Ministry of Education of China in Guizhou Medical University, Guiyang, 550004, Guizhou Province, China
| | - Keyin Zhang
- Department of Pathology, The Affiliated Hospital of Guizhou Medical University, 4 Beijing Road, Guiyang, 550004, Guizhou Province, China
| | - Xia Gao
- Department of Pathology, The Affiliated Hospital of Guizhou Medical University, 4 Beijing Road, Guiyang, 550004, Guizhou Province, China
| | - Qianchuan Ran
- Section of Forensic Science and Pathology, School of Basic Medical Sciences, Guizhou University of Traditional Chinese Medicine, Dong-Qing-Nan Road, Guiyang, 550025, Guizhou Province, China
| | - Yuanhong Xu
- Section of Forensic Science and Pathology, School of Basic Medical Sciences, Guizhou University of Traditional Chinese Medicine, Dong-Qing-Nan Road, Guiyang, 550025, Guizhou Province, China
| | - Zhi Wang
- Department of Pathology, The Affiliated Hospital of Guizhou Medical University, 4 Beijing Road, Guiyang, 550004, Guizhou Province, China
| | - Didong Lou
- Section of Forensic Science and Pathology, School of Basic Medical Sciences, Guizhou University of Traditional Chinese Medicine, Dong-Qing-Nan Road, Guiyang, 550025, Guizhou Province, China
| | - Chunhua Huang
- Section of Forensic Science and Pathology, School of Basic Medical Sciences, Guizhou University of Traditional Chinese Medicine, Dong-Qing-Nan Road, Guiyang, 550025, Guizhou Province, China
| | - Lucas Zellmer
- Department of Medicine, Hennepin County Medical Center, 730 South 8th St., Minneapolis, MN, 55415, USA
| | - Guangxue Meng
- Department of Oral and Maxillofacial Surgery, School of Stomatology, Guizhou Medical University, 9 Beijing Road, Guiyang, 550004, Guizhou Province, China
| | - Na Chen
- Department of Oral and Maxillofacial Surgery, School of Stomatology, Guizhou Medical University, 9 Beijing Road, Guiyang, 550004, Guizhou Province, China
| | - Hong Ma
- Department of Oral and Maxillofacial Surgery, School of Stomatology, Guizhou Medical University, 9 Beijing Road, Guiyang, 550004, Guizhou Province, China
| | - Zhe Wang
- State Key Laboratory of Cancer Biology, Department of Pathology, Xijing Hospital, Air Force Medical University, 169 Changle West Road, Xi'an, 710032, China
| | - Dezhong Joshua Liao
- Center for Clinical Laboratories, The Affiliated Hospital of Guizhou Medical University, 4 Beijing Rd, Guiyang, 550004, Guizhou Province, China
- Key Lab of Endemic and Ethnic Diseases of the Ministry of Education of China in Guizhou Medical University, Guiyang, 550004, Guizhou Province, China
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Yang ZY, Zhao C, Liu SL, Pan LJ, Zhu YD, Zhao JW, Wang HK, Ye YY, Qiang J, Shi LQ, Mei JW, Xie Y, Gong W, Shu YJ, Dong P, Xiang SS. NONO promotes gallbladder cancer cell proliferation by enhancing oncogenic RNA splicing of DLG1 through interaction with IGF2BP3/RBM14. Cancer Lett 2024; 587:216703. [PMID: 38341127 DOI: 10.1016/j.canlet.2024.216703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/29/2024] [Accepted: 02/01/2024] [Indexed: 02/12/2024]
Abstract
Gallbladder cancer (GBC) is a highly malignant and rapidly progressing tumor of the human biliary system, and there is an urgent need to develop new therapeutic targets and modalities. Non-POU domain-containing octamer-binding protein (NONO) is an RNA-binding protein involved in the regulation of transcription, mRNA splicing, and DNA repair. NONO expression is elevated in multiple tumors and can act as an oncogene to promote tumor progression. Here, we found that NONO was highly expressed in GBC and promoted tumor cells growth. The dysregulation of RNA splicing is a molecular feature of almost all tumor types. Accordingly, mRNA-seq and RIP-seq analysis showed that NONO promoted exon6 skipping in DLG1, forming two isomers (DLG1-FL and DLG1-S). Furthermore, lower Percent-Spliced-In (PSI) values of DLG1 were detected in tumor tissue relative to the paraneoplastic tissue, and were associated with poor patient prognosis. Moreover, DLG1-S and DLG1-FL act as tumor promoters and tumor suppressors, respectively, by regulating the YAP1/JUN pathway. N6-methyladenosine (m6A) is the most common and abundant RNA modification involved in alternative splicing processes. We identified an m6A reader, IGF2BP3, which synergizes with NONO to promote exon6 skipping in DLG1 in an m6A-dependent manner. Furthermore, IP/MS results showed that RBM14 was bound to NONO and interfered with NONO-mediated exon6 skipping of DLG1. In addition, IGF2BP3 disrupted the binding of RBM14 to NONO. Overall, our data elucidate the molecular mechanism by which NONO promotes DLG1 exon skipping, providing a basis for new therapeutic targets in GBC treatment.
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Affiliation(s)
- Zi-Yi Yang
- Laboratory of General Surgery and Department of General Surgery, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China; Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai, 200092, China.
| | - Cheng Zhao
- Laboratory of General Surgery and Department of General Surgery, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China; Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai, 200092, China.
| | - Shi-Lei Liu
- Laboratory of General Surgery and Department of General Surgery, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China; Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai, 200092, China.
| | - Li-Jia Pan
- Laboratory of General Surgery and Department of General Surgery, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China; Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai, 200092, China.
| | - Yi-di Zhu
- Laboratory of General Surgery and Department of General Surgery, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China; Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai, 200092, China.
| | - Jing-Wei Zhao
- Laboratory of General Surgery and Department of General Surgery, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China; Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai, 200092, China.
| | - Hua-Kai Wang
- Laboratory of General Surgery and Department of General Surgery, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China; Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai, 200092, China.
| | - Yuan-Yuan Ye
- Laboratory of General Surgery and Department of General Surgery, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China; Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai, 200092, China.
| | - Jing Qiang
- Laboratory of General Surgery and Department of General Surgery, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China; Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai, 200092, China.
| | - Liu-Qing Shi
- Laboratory of General Surgery and Department of General Surgery, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China; Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai, 200092, China.
| | - Jia-Wei Mei
- Laboratory of General Surgery and Department of General Surgery, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China; Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai, 200092, China.
| | - Yang Xie
- Department of Gastroenterology, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China.
| | - Wei Gong
- Laboratory of General Surgery and Department of General Surgery, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China; Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai, 200092, China.
| | - Yi-Jun Shu
- Laboratory of General Surgery and Department of General Surgery, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China; Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai, 200092, China.
| | - Ping Dong
- Laboratory of General Surgery and Department of General Surgery, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China; Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai, 200092, China.
| | - Shan-Shan Xiang
- Laboratory of General Surgery and Department of General Surgery, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai, 200092, China; Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai, 200092, China.
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Korchak JA, Jeffery ED, Bandyopadhyay S, Jordan BT, Lehe M, Watts EF, Fenix A, Wilhelm M, Sheynkman GM. IS-PRM-based peptide targeting informed by long-read sequencing for alternative proteome detection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.01.587549. [PMID: 38617311 PMCID: PMC11014528 DOI: 10.1101/2024.04.01.587549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Alternative splicing is a major contributor of transcriptomic complexity, but the extent to which transcript isoforms are translated into stable, functional protein isoforms is unclear. Furthermore, detection of relatively scarce isoform-specific peptides is challenging, with many protein isoforms remaining uncharted due to technical limitations. Recently, a family of advanced targeted MS strategies, termed internal standard parallel reaction monitoring (IS-PRM), have demonstrated multiplexed, sensitive detection of pre-defined peptides of interest. Such approaches have not yet been used to confirm existence of novel peptides. Here, we present a targeted proteogenomic approach that leverages sample-matched long-read RNA sequencing (LR RNAseq) data to predict potential protein isoforms with prior transcript evidence. Predicted tryptic isoform-specific peptides, which are specific to individual gene product isoforms, serve as "triggers" and "targets" in the IS-PRM method, Tomahto. Using the model human stem cell line WTC11, LR RNAseq data were generated and used to inform the generation of synthetic standards for 192 isoform-specific peptides (114 isoforms from 55 genes). These synthetic "trigger" peptides were labeled with super heavy tandem mass tags (TMT) and spiked into TMT-labeled WTC11 tryptic digest, predicted to contain corresponding endogenous "target" peptides. Compared to DDA mode, Tomahto increased detectability of isoforms by 3.6-fold, resulting in the identification of five previously unannotated isoforms. Our method detected protein isoform expression for 43 out of 55 genes corresponding to 54 resolved isoforms. This LR RNA seq-informed Tomahto targeted approach, called LRP-IS-PRM, is a new modality for generating protein-level evidence of alternative isoforms - a critical first step in designing functional studies and eventually clinical assays.
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Affiliation(s)
- Jennifer A. Korchak
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Erin D. Jeffery
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Saikat Bandyopadhyay
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA, USA
| | - Ben T. Jordan
- Cancer Genomics Research Laboratory, Frederick National Laboratory for Cancer Research, Frederick, MD USA
| | - Micah Lehe
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Emily F. Watts
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Aidan Fenix
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
| | - Mathias Wilhelm
- Computational Mass Spectrometry, Technical University of Munich (TUM), D-85354 Freising, Germany
| | - Gloria M. Sheynkman
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, USA
- UVA Comprehensive Cancer Center, University of Virginia, Charlottesville, VA, USA
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Murali M, Saquing J, Lu S, Gao Z, Jordan B, Wakefield ZP, Fiszbein A, Cooper DR, Castaldi PJ, Korkin D, Sheynkman G. Biosurfer for systematic tracking of regulatory mechanisms leading to protein isoform diversity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.15.585320. [PMID: 38559226 PMCID: PMC10980011 DOI: 10.1101/2024.03.15.585320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Long-read RNA sequencing has shed light on transcriptomic complexity, but questions remain about the functionality of downstream protein products. We introduce Biosurfer, a computational approach for comparing protein isoforms, while systematically tracking the transcriptional, splicing, and translational variations that underlie differences in the sequences of the protein products. Using Biosurfer, we analyzed the differences in 32,799 pairs of GENCODE annotated protein isoforms, finding a majority (70%) of variable N-termini are due to the alternative transcription start sites, while only 9% arise from 5' UTR alternative splicing. Biosurfer's detailed tracking of nucleotide-to-residue relationships helped reveal an uncommonly tracked source of single amino acid residue changes arising from the codon splits at junctions. For 17% of internal sequence changes, such split codon patterns lead to single residue differences, termed "ragged codons". Of variable C-termini, 72% involve splice- or intron retention-induced reading frameshifts. We found an unusual pattern of reading frame changes, in which the first frameshift is closely followed by a distinct second frameshift that restores the original frame, which we term a "snapback" frameshift. We analyzed long read RNA-seq-predicted proteome of a human cell line and found similar trends as compared to our GENCODE analysis, with the exception of a higher proportion of isoforms predicted to undergo nonsense-mediated decay. Biosurfer's comprehensive characterization of long-read RNA-seq datasets should accelerate insights of the functional role of protein isoforms, providing mechanistic explanation of the origins of the proteomic diversity driven by the alternative splicing. Biosurfer is available as a Python package at https://github.com/sheynkman-lab/biosurfer.
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Affiliation(s)
- Mayank Murali
- Broad Institute of MIT and Harvard University, Cambridge, MA, USA
| | - Jamie Saquing
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - Senbao Lu
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA, USA
- Computer Science Department, Worcester Polytechnic Institute, Worcester, MA, USA
| | - Ziyang Gao
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA, USA
- Computer Science Department, Worcester Polytechnic Institute, Worcester, MA, USA
| | - Ben Jordan
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - Zachary Peters Wakefield
- Bioinformatics Program, Boston University, Boston, MA, USA
- Department of Biology, Boston University, Boston, MA, USA
| | - Ana Fiszbein
- Bioinformatics Program, Boston University, Boston, MA, USA
- Department of Biology, Boston University, Boston, MA, USA
| | - David R. Cooper
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - Peter J. Castaldi
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital, Boston, MA, USA
- Division of General Medicine and Primary Care, Department of Medicine, Brigham and Women’s Hospital, Boston, MA, USA
| | - Dmitry Korkin
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA, USA
- Computer Science Department, Worcester Polytechnic Institute, Worcester, MA, USA
| | - Gloria Sheynkman
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, USA
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA, USA
- UVA Cancer Center, University of Virginia, Charlottesville, VA, USA
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Wijeratne S, Gonzalez MEH, Roach K, Miller KE, Schieffer KM, Fitch JR, Leonard J, White P, Kelly BJ, Cottrell CE, Mardis ER, Wilson RK, Miller AR. Full-length isoform concatenation sequencing to resolve cancer transcriptome complexity. BMC Genomics 2024; 25:122. [PMID: 38287261 PMCID: PMC10823626 DOI: 10.1186/s12864-024-10021-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 01/16/2024] [Indexed: 01/31/2024] Open
Abstract
BACKGROUND Cancers exhibit complex transcriptomes with aberrant splicing that induces isoform-level differential expression compared to non-diseased tissues. Transcriptomic profiling using short-read sequencing has utility in providing a cost-effective approach for evaluating isoform expression, although short-read assembly displays limitations in the accurate inference of full-length transcripts. Long-read RNA sequencing (Iso-Seq), using the Pacific Biosciences (PacBio) platform, can overcome such limitations by providing full-length isoform sequence resolution which requires no read assembly and represents native expressed transcripts. A constraint of the Iso-Seq protocol is due to fewer reads output per instrument run, which, as an example, can consequently affect the detection of lowly expressed transcripts. To address these deficiencies, we developed a concatenation workflow, PacBio Full-Length Isoform Concatemer Sequencing (PB_FLIC-Seq), designed to increase the number of unique, sequenced PacBio long-reads thereby improving overall detection of unique isoforms. In addition, we anticipate that the increase in read depth will help improve the detection of moderate to low-level expressed isoforms. RESULTS In sequencing a commercial reference (Spike-In RNA Variants; SIRV) with known isoform complexity we demonstrated a 3.4-fold increase in read output per run and improved SIRV recall when using the PB_FLIC-Seq method compared to the same samples processed with the Iso-Seq protocol. We applied this protocol to a translational cancer case, also demonstrating the utility of the PB_FLIC-Seq method for identifying differential full-length isoform expression in a pediatric diffuse midline glioma compared to its adjacent non-malignant tissue. Our data analysis revealed increased expression of extracellular matrix (ECM) genes within the tumor sample, including an isoform of the Secreted Protein Acidic and Cysteine Rich (SPARC) gene that was expressed 11,676-fold higher than in the adjacent non-malignant tissue. Finally, by using the PB_FLIC-Seq method, we detected several cancer-specific novel isoforms. CONCLUSION This work describes a concatenation-based methodology for increasing the number of sequenced full-length isoform reads on the PacBio platform, yielding improved discovery of expressed isoforms. We applied this workflow to profile the transcriptome of a pediatric diffuse midline glioma and adjacent non-malignant tissue. Our findings of cancer-specific novel isoform expression further highlight the importance of long-read sequencing for characterization of complex tumor transcriptomes.
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Affiliation(s)
- Saranga Wijeratne
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH, 43215, USA
| | - Maria E Hernandez Gonzalez
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH, 43215, USA
| | - Kelli Roach
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH, 43215, USA
| | - Katherine E Miller
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH, 43215, USA
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Kathleen M Schieffer
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH, 43215, USA
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
- Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - James R Fitch
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH, 43215, USA
| | - Jeffrey Leonard
- Department of Neurosurgery, Nationwide Children's Hospital, Columbus, OH, USA
- Department of Neurosurgery, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Peter White
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH, 43215, USA
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Benjamin J Kelly
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH, 43215, USA
| | - Catherine E Cottrell
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH, 43215, USA
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
- Department of Pathology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Elaine R Mardis
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH, 43215, USA
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
- Department of Neurosurgery, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Richard K Wilson
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH, 43215, USA
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Anthony R Miller
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH, 43215, USA.
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7
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Nowzari ZR, Hale M, Ellis J, Biaesch S, Vangaveti S, Reddy K, Chen AA, Berglund JA. Mutation of two intronic nucleotides alters RNA structure and dynamics inhibiting MBNL1 and RBFOX1 regulated splicing of the Insulin Receptor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.08.574689. [PMID: 38260517 PMCID: PMC10802415 DOI: 10.1101/2024.01.08.574689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Alternative splicing (AS) of Exon 11 of the Insulin Receptor ( INSR ) is highly regulated and disrupted in several human disorders. To better understand INSR exon 11 AS regulation, splicing activity of an INSR exon 11 minigene reporter was measured across a gradient of the AS regulator muscleblind-like 1 protein (MBNL1). The RNA-binding protein Fox-1 (RBFOX1) was added to determine its impact on MBNL1-regulated splicing. The role of the RBFOX1 UGCAUG binding site within intron 11 was assessed across the MBNL1 gradient. Mutating the UGCAUG motif inhibited RBFOX1 regulation of exon 11 and had the unexpected effect of reducing MBNL1 regulation of this exon. Molecular dynamics simulations showed that exon 11 and the adjacent RNA adopts a dynamically stable conformation. Mutation of the RBFOX1 binding site altered RNA structure and dynamics, while a mutation that created an optimal MBNL1 binding site at the RBFOX1 site shifted the RNA back to wild type. An antisense oligonucleotide (ASO) was used to confirm the structure in this region of the pre-mRNA. This example of intronic mutations shifting pre-mRNA structure and dynamics to modulate splicing suggests RNA structure and dynamics should be taken into consideration for AS regulation and therapeutic interventions targeting pre-mRNA.
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8
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Sinitcyn P, Richards AL, Weatheritt RJ, Brademan DR, Marx H, Shishkova E, Meyer JG, Hebert AS, Westphall MS, Blencowe BJ, Cox J, Coon JJ. Global detection of human variants and isoforms by deep proteome sequencing. Nat Biotechnol 2023; 41:1776-1786. [PMID: 36959352 PMCID: PMC10713452 DOI: 10.1038/s41587-023-01714-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 02/15/2023] [Indexed: 03/25/2023]
Abstract
An average shotgun proteomics experiment detects approximately 10,000 human proteins from a single sample. However, individual proteins are typically identified by peptide sequences representing a small fraction of their total amino acids. Hence, an average shotgun experiment fails to distinguish different protein variants and isoforms. Deeper proteome sequencing is therefore required for the global discovery of protein isoforms. Using six different human cell lines, six proteases, deep fractionation and three tandem mass spectrometry fragmentation methods, we identify a million unique peptides from 17,717 protein groups, with a median sequence coverage of approximately 80%. Direct comparison with RNA expression data provides evidence for the translation of most nonsynonymous variants. We have also hypothesized that undetected variants likely arise from mutation-induced protein instability. We further observe comparable detection rates for exon-exon junction peptides representing constitutive and alternative splicing events. Our dataset represents a resource for proteoform discovery and provides direct evidence that most frame-preserving alternatively spliced isoforms are translated.
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Affiliation(s)
- Pavel Sinitcyn
- Computational Systems Biochemistry Research Group, Max Planck Institute of Biochemistry, Martinsried, Germany
- Morgridge Institute for Research, Madison, WI, USA
| | - Alicia L Richards
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin-Madison, Madison, WI, USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Robert J Weatheritt
- EMBL Australia and Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Dain R Brademan
- Morgridge Institute for Research, Madison, WI, USA
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Harald Marx
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Evgenia Shishkova
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Jesse G Meyer
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Alexander S Hebert
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin-Madison, Madison, WI, USA
| | - Michael S Westphall
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Benjamin J Blencowe
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Jürgen Cox
- Computational Systems Biochemistry Research Group, Max Planck Institute of Biochemistry, Martinsried, Germany.
| | - Joshua J Coon
- Morgridge Institute for Research, Madison, WI, USA.
- National Center for Quantitative Biology of Complex Systems, University of Wisconsin-Madison, Madison, WI, USA.
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA.
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA.
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9
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Farhadieh ME, Ghaedi K. Analyzing alternative splicing in Alzheimer's disease postmortem brain: a cell-level perspective. Front Mol Neurosci 2023; 16:1237874. [PMID: 37799732 PMCID: PMC10548223 DOI: 10.3389/fnmol.2023.1237874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Accepted: 09/01/2023] [Indexed: 10/07/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease with no effective cure that attacks the brain's cells resulting in memory loss and changes in behavior and language skills. Alternative splicing is a highly regulated process influenced by specific cell types and has been implicated in age-related disorders such as neurodegenerative diseases. A comprehensive detection of alternative splicing events (ASEs) at the cellular level in postmortem brain tissue can provide valuable insights into AD pathology. Here, we provided cell-level ASEs in postmortem brain tissue by employing bioinformatics pipelines on a bulk RNA sequencing study sorted by cell types and two single-cell RNA sequencing studies from the prefrontal cortex. This comprehensive analysis revealed previously overlooked splicing and expression changes in AD patient brains. Among the observed alterations were changed in the splicing and expression of transcripts associated with chaperones, including CLU in astrocytes and excitatory neurons, PTGDS in astrocytes and endothelial cells, and HSP90AA1 in microglia and tauopathy-afflicted neurons, which were associated with differential expression of the splicing factor DDX5. In addition, novel, unknown transcripts were altered, and structural changes were observed in lncRNAs such as MEG3 in neurons. This work provides a novel strategy to identify the notable ASEs at the cell level in neurodegeneration, which revealed cell type-specific splicing changes in AD. This finding may contribute to interpreting associations between splicing and neurodegenerative disease outcomes.
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Affiliation(s)
| | - Kamran Ghaedi
- Department of Cell and Molecular Biology and Microbiology, Faculty of Biological Sciences and Technology, University of Isfahan, Isfahan, Iran
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10
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Schertzer MD, Stirn A, Isaev K, Pereira L, Das A, Harbison C, Park SH, Wessels HH, Sanjana NE, Knowles DA. Cas13d-mediated isoform-specific RNA knockdown with a unified computational and experimental toolbox. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.12.557474. [PMID: 37745416 PMCID: PMC10515814 DOI: 10.1101/2023.09.12.557474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Alternative splicing is an essential mechanism for diversifying proteins, in which mature RNA isoforms produce proteins with potentially distinct functions. Two major challenges in characterizing the cellular function of isoforms are the lack of experimental methods to specifically and efficiently modulate isoform expression and computational tools for complex experimental design. To address these gaps, we developed and methodically tested a strategy which pairs the RNA-targeting CRISPR/Cas13d system with guide RNAs that span exon-exon junctions in the mature RNA. We performed a high-throughput essentiality screen, quantitative RT-PCR assays, and PacBio long read sequencing to affirm our ability to specifically target and robustly knockdown individual RNA isoforms. In parallel, we provide computational tools for experimental design and screen analysis. Considering all possible splice junctions annotated in GENCODE for multi-isoform genes and our gRNA efficacy predictions, we estimate that our junction-centric strategy can uniquely target up to 89% of human RNA isoforms, including 50,066 protein-coding and 11,415 lncRNA isoforms. Importantly, this specificity spans all splicing and transcriptional events, including exon skipping and inclusion, alternative 5' and 3' splice sites, and alternative starts and ends.
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Affiliation(s)
- Megan D Schertzer
- New York Genome Center, New York, NY
- Department of Computer Science, Columbia University, New York, NY
| | - Andrew Stirn
- New York Genome Center, New York, NY
- Department of Computer Science, Columbia University, New York, NY
| | - Keren Isaev
- New York Genome Center, New York, NY
- Department of Systems Biology, Columbia University, New York, NY
| | | | - Anjali Das
- New York Genome Center, New York, NY
- Department of Computer Science, Columbia University, New York, NY
| | | | - Stella H Park
- New York Genome Center, New York, NY
- Department of Biomedical Engineering, Columbia University, New York, NY
| | - Hans-Hermann Wessels
- New York Genome Center, New York, NY
- Department of Biology, New York University, New York, NY
| | - Neville E Sanjana
- New York Genome Center, New York, NY
- Department of Biology, New York University, New York, NY
| | - David A Knowles
- New York Genome Center, New York, NY
- Department of Computer Science, Columbia University, New York, NY
- Department of Systems Biology, Columbia University, New York, NY
- Data Science Institute, Columbia University, New York, NY
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11
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Chang J, Yan S, Geng Z, Wang Z. Inhibition of splicing factors SF3A3 and SRSF5 contributes to As 3+/Se 4+ combination-mediated proliferation suppression and apoptosis induction in acute promyelocytic leukemia cells. Arch Biochem Biophys 2023; 743:109677. [PMID: 37356608 DOI: 10.1016/j.abb.2023.109677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/28/2023] [Accepted: 06/22/2023] [Indexed: 06/27/2023]
Abstract
The low-dose combination of Arsenite (As3+) and selenite (Se4+) has the advantages of lower biological toxicity and better curative effects for acute promyelocytic leukemia (APL) therapy. However, the underlying mechanisms remain unclear. Here, based on the fact that the combination of 2 μM A3+ plus 4 μM Se4+ possessed a stronger anti-leukemic effect on APL cell line NB4 as compared with each individual, we employed iTRAQ-based quantitative proteomics to identify a total of 58 proteins that were differentially expressed after treatment with As3+/Se4+ combination rather than As3+ or Se4+ alone, the majority of which were involved in spliceosome pathway. Among them, eight proteins stood out by virtue of their splicing function and significant changes. They were validated as being decreased in mRNA and protein levels under As3+/Se4+ combination treatment. Further functional studies showed that only knockdown of two splicing factors, SF3A3 and SRSF5, suppressed the growth of NB4 cells. The reduction of SF3A3 was found to cause G1/S cell cycle arrest, which resulted in proliferation inhibition. Moreover, SRSF5 downregulation induced cell apoptosis through the activation of caspase-3. Taken together, these findings indicate that SF3A3 and SRSF5 function as pro-leukemic factors and can be potential novel therapeutic targets for APL.
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Affiliation(s)
- Jiayin Chang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, PR China
| | - Shihai Yan
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, PR China
| | - Zhirong Geng
- College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210046, PR China.
| | - Zhilin Wang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, PR China.
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12
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Hu Y, Gouru A, Wang K. DELongSeq for efficient detection of differential isoform expression from long-read RNA-seq data. NAR Genom Bioinform 2023; 5:lqad019. [PMID: 36879902 PMCID: PMC9985341 DOI: 10.1093/nargab/lqad019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 01/12/2023] [Accepted: 02/16/2023] [Indexed: 03/07/2023] Open
Abstract
Conventional gene expression quantification approaches, such as microarrays or quantitative PCR, have similar variations of estimates for all genes. However, next-generation short-read or long-read sequencing use read counts to estimate expression levels with much wider dynamic ranges. In addition to the accuracy of estimated isoform expression, efficiency, which measures the degree of estimation uncertainty, is also an important factor for downstream analysis. Instead of read count, we present DELongSeq, which employs information matrix of EM algorithm to quantify uncertainty of isoform expression estimates to improve estimation efficiency. DELongSeq uses random-effect regression model for the analysis of DE isoform, in that within-study variation represents variable precision in isoform expression estimation and between-study variation represents variation in isoform expression levels across samples. More importantly, DELongSeq allows 1 case versus 1 control comparison of differential expression, which has specific application scenarios in precision medicine (such as before versus after treatment, or tumor versus stromal tissues). Through extensive simulations and analysis of several RNA-Seq datasets, we show that the uncertainty quantification approach is computationally reliable, and can improve the power of differential expression (DE) analysis of isoforms or genes. In summary, DELongSeq allows for efficient detection of differential isoform/gene expression from long-read RNA-Seq data.
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Affiliation(s)
- Yu Hu
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Anagha Gouru
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Kai Wang
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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13
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Abstract
Dysregulated RNA splicing is a molecular feature that characterizes almost all tumour types. Cancer-associated splicing alterations arise from both recurrent mutations and altered expression of trans-acting factors governing splicing catalysis and regulation. Cancer-associated splicing dysregulation can promote tumorigenesis via diverse mechanisms, contributing to increased cell proliferation, decreased apoptosis, enhanced migration and metastatic potential, resistance to chemotherapy and evasion of immune surveillance. Recent studies have identified specific cancer-associated isoforms that play critical roles in cancer cell transformation and growth and demonstrated the therapeutic benefits of correcting or otherwise antagonizing such cancer-associated mRNA isoforms. Clinical-grade small molecules that modulate or inhibit RNA splicing have similarly been developed as promising anticancer therapeutics. Here, we review splicing alterations characteristic of cancer cell transcriptomes, dysregulated splicing's contributions to tumour initiation and progression, and existing and emerging approaches for targeting splicing for cancer therapy. Finally, we discuss the outstanding questions and challenges that must be addressed to translate these findings into the clinic.
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Affiliation(s)
- Robert K Bradley
- Computational Biology Program, Public Health Sciences Division and Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA.
| | - Olga Anczuków
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA.
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT, USA.
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14
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Apostolidi M, Stamatopoulou V. Aberrant splicing in human cancer: An RNA structural code point of view. Front Pharmacol 2023; 14:1137154. [PMID: 36909167 PMCID: PMC9995731 DOI: 10.3389/fphar.2023.1137154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 02/14/2023] [Indexed: 02/25/2023] Open
Abstract
Alternative splicing represents an essential process that occurs widely in eukaryotes. In humans, most genes undergo alternative splicing to ensure transcriptome and proteome diversity reflecting their functional complexity. Over the last decade, aberrantly spliced transcripts due to mutations in cis- or trans-acting splicing regulators have been tightly associated with cancer development, largely drawing scientific attention. Although a plethora of single proteins, ribonucleoproteins, complexed RNAs, and short RNA sequences have emerged as nodal contributors to the splicing cascade, the role of RNA secondary structures in warranting splicing fidelity has been underestimated. Recent studies have leveraged the establishment of novel high-throughput methodologies and bioinformatic tools to shed light on an additional layer of splicing regulation in the context of RNA structural elements. This short review focuses on the most recent available data on splicing mechanism regulation on the basis of RNA secondary structure, emphasizing the importance of the complex RNA G-quadruplex structures (rG4s), and other specific RNA motifs identified as splicing silencers or enhancers. Moreover, it intends to provide knowledge on newly established techniques that allow the identification of RNA structural elements and highlight the potential to develop new RNA-oriented therapeutic strategies against cancer.
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Affiliation(s)
- Maria Apostolidi
- Agilent Laboratories, Agilent Technologies, Santa Clara, CA, United States
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15
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Kaczynski TJ, Au ED, Farkas MH. Oxidative stress alters transcript localization of disease-associated genes in the retinal pigment epithelium. Mol Vis 2022; 28:340-351. [PMID: 36338668 PMCID: PMC9603899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 09/30/2022] [Indexed: 11/29/2022] Open
Abstract
PURPOSE Nuclear retention is a mechanism whereby excess RNA transcripts are stored in the event that a cell needs to quickly respond to a stimulus; maintaining proper nuclear-to-cytoplasmic balance is important for cellular homeostasis and cell function. There are many mechanisms that are employed to determine whether to retain a transcript or export it to the cytoplasm, although the extent to which tissue or cell type, internal and external stressors, and disease pathogenesis affect this process is not yet clear. As the most biochemically active tissue in the body, the retina must mitigate endogenous and exogenous stressors to maintain cell health and tissue function. Oxidative stress, believed to contribute to the pathogenesis or progression of age-related macular degeneration (AMD) and inherited retinal dystrophies (IRDs), is produced both internally from biochemical processes as well as externally from environmental insult. Here, we evaluate the effect of oxidative stress on transcript localization in the retinal pigment epithelium (RPE), with specific focus on transcripts related to RPE function and disease. METHODS We performed poly(A) RNA sequencing on nuclear and cytoplasmic fractions from human induced pluripotent stem cell-derived retinal pigment epithelium (iPSC-RPE) cells exposed to hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), as well as on untreated controls. RESULTS Under normal conditions, the number of mRNA transcripts retained in the nucleus exceeded that found in studies on other tissues. Further, the nuclear-to-cytoplasmic ratio of transcripts was altered following oxidative stress, as was the retention of genes associated with AMD and IRDs, as well as those that are important for RPE physiology. CONCLUSIONS These results provide a localization catalog of all expressed mRNA in iPSC-RPE under normal conditions and after exposure to H<sub>2</sub>O<sub>2</sub>, shedding light on the extent to which H<sub>2</sub>O<sub>2</sub> alters transcript localization and potentially offering insight into one mechanism through which oxidative stress may contribute to the progression of visual disorders.
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Affiliation(s)
- Tadeusz J. Kaczynski
- Department of Ophthalmology, State University of New York at Buffalo, Buffalo, NY,Research Service, VA Medical Center, Buffalo, NY
| | - Elizabeth D. Au
- Department of Ophthalmology, State University of New York at Buffalo, Buffalo, NY
| | - Michael H. Farkas
- Department of Ophthalmology, State University of New York at Buffalo, Buffalo, NY,Research Service, VA Medical Center, Buffalo, NY,Department of Biochemistry, State University of New York at Buffalo, Buffalo, NY
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16
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Pozo F, Rodriguez JM, Martínez Gómez L, Vázquez J, Tress ML. APPRIS principal isoforms and MANE Select transcripts define reference splice variants. Bioinformatics 2022; 38:ii89-ii94. [PMID: 36124785 PMCID: PMC9486585 DOI: 10.1093/bioinformatics/btac473] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
MOTIVATION Selecting the splice variant that best represents a coding gene is a crucial first step in many experimental analyses, and vital for mapping clinically relevant variants. This study compares the longest isoforms, MANE Select transcripts, APPRIS principal isoforms, and expression data, and aims to determine which method is best for selecting biological important reference splice variants for large-scale analyses. RESULTS Proteomics analyses and human genetic variation data suggest that most coding genes have a single main protein isoform. We show that APPRIS principal isoforms and MANE Select transcripts best describe these main cellular isoforms, and find that using the longest splice variant as the representative is a poor strategy. Exons unique to the longest splice isoforms are not under selective pressure, and so are unlikely to be functionally relevant. Expression data are also a poor means of selecting the main splice variant. APPRIS principal and MANE Select exons are under purifying selection, while exons specific to alternative transcripts are not. There are MANE and APPRIS representatives for almost 95% of genes, and where they agree they are particularly effective, coinciding with the main proteomics isoform for over 98.2% of genes. AVAILABILITY AND IMPLEMENTATION APPRIS principal isoforms for human, mouse and other model species can be downloaded from the APPRIS database (https://appris.bioinfo.cnio.es), GENCODE genes (https://www.gencodegenes.org/) and the Ensembl website (https://www.ensembl.org). MANE Select transcripts for the human reference set are available from the Ensembl, GENCODE and RefSeq databases (https://www.ncbi.nlm.nih.gov/refseq/). Lists of splice variants where MANE and APPRIS coincide are available from the APPRIS database. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Fernando Pozo
- Bioinformatics Unit, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain
| | - José Manuel Rodriguez
- Cardiovascular Proteomics Laboratory, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029 Madrid, Spain
| | - Laura Martínez Gómez
- Bioinformatics Unit, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain
| | - Jesús Vázquez
- Cardiovascular Proteomics Laboratory, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029 Madrid, Spain,CIBER de Investigaciones Cardiovasculares (CIBERCV), 28029 Madrid, Spain
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17
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Wright CJ, Smith CWJ, Jiggins CD. Alternative splicing as a source of phenotypic diversity. Nat Rev Genet 2022; 23:697-710. [PMID: 35821097 DOI: 10.1038/s41576-022-00514-4] [Citation(s) in RCA: 96] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2022] [Indexed: 12/27/2022]
Abstract
A major goal of evolutionary genetics is to understand the genetic processes that give rise to phenotypic diversity in multicellular organisms. Alternative splicing generates multiple transcripts from a single gene, enriching the diversity of proteins and phenotypic traits. It is well established that alternative splicing contributes to key innovations over long evolutionary timescales, such as brain development in bilaterians. However, recent developments in long-read sequencing and the generation of high-quality genome assemblies for diverse organisms has facilitated comparisons of splicing profiles between closely related species, providing insights into how alternative splicing evolves over shorter timescales. Although most splicing variants are probably non-functional, alternative splicing is nonetheless emerging as a dynamic, evolutionarily labile process that can facilitate adaptation and contribute to species divergence.
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Affiliation(s)
- Charlotte J Wright
- Tree of Life, Wellcome Sanger Institute, Cambridge, UK. .,Department of Zoology, University of Cambridge, Cambridge, UK.
| | | | - Chris D Jiggins
- Department of Zoology, University of Cambridge, Cambridge, UK.
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18
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Edwards HE, Gorelick DA. The evolution and structure/function of bHLH-PAS transcription factor family. Biochem Soc Trans 2022; 50:1227-1243. [PMID: 35695677 PMCID: PMC10584024 DOI: 10.1042/bst20211225] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 02/06/2023]
Abstract
Proteins that contain basic helix-loop-helix (bHLH) and Per-Arnt-Sim motifs (PAS) function as transcription factors. bHLH-PAS proteins exhibit essential and diverse functions throughout the body, from cell specification and differentiation in embryonic development to the proper function of organs like the brain and liver in adulthood. bHLH-PAS proteins are divided into two classes, which form heterodimers to regulate transcription. Class I bHLH-PAS proteins are typically activated in response to specific stimuli, while class II proteins are expressed more ubiquitously. Here, we discuss the general structure and functions of bHLH-PAS proteins throughout the animal kingdom, including family members that do not fit neatly into the class I-class II organization. We review heterodimerization between class I and class II bHLH-PAS proteins, binding partner selectivity and functional redundancy. Finally, we discuss the evolution of bHLH-PAS proteins, and why a class I protein essential for cardiovascular development in vertebrates like chicken and fish is absent from mammals.
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Affiliation(s)
- Hailey E Edwards
- Center for Precision Environmental Health, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, U.S.A
| | - Daniel A Gorelick
- Center for Precision Environmental Health, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, U.S.A
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19
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Krishnan VS, Kõks S. Transcriptional Basis of Psoriasis from Large Scale Gene Expression Studies: The Importance of Moving towards a Precision Medicine Approach. Int J Mol Sci 2022; 23:ijms23116130. [PMID: 35682804 PMCID: PMC9181806 DOI: 10.3390/ijms23116130] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/23/2022] [Accepted: 05/26/2022] [Indexed: 12/14/2022] Open
Abstract
Transcriptome profiling techniques, such as microarrays and RNA sequencing (RNA-seq), are valuable tools for deciphering the regulatory network underlying psoriasis and have revealed large number of differentially expressed genes in lesional and non-lesional skin. Such approaches provide a more precise measurement of transcript levels and their isoforms than any other methods. Large cohort transcriptomic analyses have greatly improved our understanding of the physiological and molecular mechanisms underlying disease pathogenesis and progression. Here, we mostly review the findings of some important large scale psoriatic transcriptomic studies, and the benefits of such studies in elucidating potential therapeutic targets and biomarkers for psoriasis treatment. We also emphasised the importance of looking into the alternatively spliced RNA isoforms/transcripts in psoriasis, rather than focussing only on the gene-level annotation. The neutrophil and blood transcriptome signature in psoriasis is also briefly reviewed, as it provides the immune status information of patients and is a less invasive platform. The application of precision medicine in current management of psoriasis, by combining transcriptomic data, improves the clinical response outcome in individual patients. Drugs tailored to individual patient’s genetic profile will greatly improve patient outcome and cost savings for the healthcare system.
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Affiliation(s)
- Vidya S. Krishnan
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Discovery Way, Murdoch, WA 6150, Australia;
- Perron Institute for Neurological and Translational Science, 8 Verdun Street, Nedlands, WA 6009, Australia
| | - Sulev Kõks
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Discovery Way, Murdoch, WA 6150, Australia;
- Perron Institute for Neurological and Translational Science, 8 Verdun Street, Nedlands, WA 6009, Australia
- Correspondence:
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