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Xiao Y, Xie S, Li HD, Liu Y, Zhang H, Zuo X, Zhu H, Li Y, Luo H. Characterised intron retention profiles in muscle tissue of idiopathic inflammatory myopathy subtypes. Ann Rheum Dis 2024; 83:901-914. [PMID: 38302260 DOI: 10.1136/ard-2023-225035] [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: 09/21/2023] [Accepted: 01/23/2024] [Indexed: 02/03/2024]
Abstract
OBJECTIVES Idiopathic inflammatory myopathies (IIMs) are a group of heterogeneous autoimmune diseases. Intron retention (IR) serves as an important post-transcriptional and translational regulatory mechanism. This study aims to identify changes in IR profiles in IIM subtypes, investigating their influence on proteins and their correlations with clinical features. METHODS RNA sequencing and liquid chromatography-tandem mass spectrometry were performed on muscle tissues obtained from 174 patients with IIM and 19 controls, following QC procedures. GTFtools and iREAD software were used for IR identification. An analysis of differentially expressed IRs (DEIs), exons and proteins was carried out using edgeR or DEP. Functional analysis was performed with clusterProfiler, and SPIRON was used to assess splicing factors. RESULTS A total of 6783 IRs located in 3111 unique genes were identified in all IIM subtypes compared with controls. IIM subtype-specific DEIs were associated with the pathogenesis of respective IIM subtypes. Splicing factors YBX1 and HSPA2 exhibited the most changes in dermatomyositis and immune-mediated necrotising myopathy. Increased IR was associated with reduced protein expression. Some of the IIM-specific DEIs were correlated with clinical parameters (skin rash, MMT-8 scores and muscle enzymes) and muscle histopathological features (myofiber necrosis, regeneration and inflammation). IRs in IFIH1 and TRIM21 were strongly correlated with anti-MDA5+ antibody, while IRs in SRP14 were associated with anti-SRP+ antibody. CONCLUSION This study revealed distinct IRs and specific splicing factors associated with IIM subtypes, which might be contributing to the pathogenesis of IIM. We also emphasised the potential impact of IR on protein expression in IIM muscles.
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Affiliation(s)
- Yizhi Xiao
- Department of Rheumatology and Immunology, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
- Provincial Clinical Research Center for Rheumatic and Immunologic Diseases, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
| | - Shasha Xie
- Department of Rheumatology and Immunology, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
- Provincial Clinical Research Center for Rheumatic and Immunologic Diseases, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
| | - Hong-Dong Li
- School of Computer Science and Engineering, Central South University, Changsha, Hunan, China PR
| | - Yanjuan Liu
- Institute of Emergency Medicine, Hunan Provincial People's Hospital/The First Affiliated Hospital of Hunan Normal University, Changsha, Hunan, China PR
| | - Huali Zhang
- Department of Pathophysiology, Xiangya School of Medicine, Central South University, Changsha, Hunan, China PR
| | - Xiaoxia Zuo
- Department of Rheumatology and Immunology, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
- Provincial Clinical Research Center for Rheumatic and Immunologic Diseases, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
| | - Honglin Zhu
- Department of Rheumatology and Immunology, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
- Provincial Clinical Research Center for Rheumatic and Immunologic Diseases, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
| | - Yisha Li
- Department of Rheumatology and Immunology, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
- Provincial Clinical Research Center for Rheumatic and Immunologic Diseases, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
| | - Hui Luo
- Department of Rheumatology and Immunology, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
- Provincial Clinical Research Center for Rheumatic and Immunologic Diseases, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China PR
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2
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Kashyap MK, Karathia H, Kumar D, Vera Alvarez R, Forero-Forero JV, Moreno E, Lujan JV, Amaya-Chanaga CI, Vidal NM, Yu Z, Ghia EM, Lengerke-Diaz PA, Achinko D, Choi MY, Rassenti LZ, Mariño-Ramírez L, Mount SM, Hannenhalli S, Kipps TJ, Castro JE. Aberrant spliceosome activity via elevated intron retention and upregulation and phosphorylation of SF3B1 in chronic lymphocytic leukemia. MOLECULAR THERAPY. NUCLEIC ACIDS 2024; 35:102202. [PMID: 38846999 PMCID: PMC11154714 DOI: 10.1016/j.omtn.2024.102202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 04/24/2024] [Indexed: 06/09/2024]
Abstract
Splicing factor 3b subunit 1 (SF3B1) is the largest subunit and core component of the spliceosome. Inhibition of SF3B1 was associated with an increase in broad intron retention (IR) on most transcripts, suggesting that IR can be used as a marker of spliceosome inhibition in chronic lymphocytic leukemia (CLL) cells. Furthermore, we separately analyzed exonic and intronic mapped reads on annotated RNA-sequencing transcripts obtained from B cells (n = 98 CLL patients) and healthy volunteers (n = 9). We measured intron/exon ratio to use that as a surrogate for alternative RNA splicing (ARS) and found that 66% of CLL-B cell transcripts had significant IR elevation compared with normal B cells (NBCs) and that correlated with mRNA downregulation and low expression levels. Transcripts with the highest IR levels belonged to biological pathways associated with gene expression and RNA splicing. A >2-fold increase of active pSF3B1 was observed in CLL-B cells compared with NBCs. Additionally, when the CLL-B cells were treated with macrolides (pladienolide-B), a significant decrease in pSF3B1, but not total SF3B1 protein, was observed. These findings suggest that IR/ARS is increased in CLL, which is associated with SF3B1 phosphorylation and susceptibility to SF3B1 inhibitors. These data provide additional support to the relevance of ARS in carcinogenesis and evidence of pSF3B1 participation in this process.
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Affiliation(s)
- Manoj Kumar Kashyap
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
- Division of Hematology Oncology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Amity Stem Cell Institute, Amity Medical School, Amity University Haryana, Panchgaon (Manesar), Gurugram (HR) 122413, India
| | - Hiren Karathia
- Advanced Biomedical Computational Science and National Center for Advancing Translational Sciences, National Cancer Institute, National Institutes of Health, Frederick, MD, USA
- Greenwood Genetic Center, Greenwood, SC, USA
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD 20742, USA
| | - Deepak Kumar
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
| | - Roberto Vera Alvarez
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | | | - Eider Moreno
- Department of Internal Medicine, Division of Hematology-Oncology, Mayo Clinic, Phoenix, AZ 85054, USA
| | - Juliana Velez Lujan
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
| | | | - Newton Medeiros Vidal
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Zhe Yu
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
| | - Emanuela M. Ghia
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
- Division of Hematology Oncology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Center for Novel Therapeutics, University of California, San Diego, La Jolla, CA 92037, USA
| | - Paula A. Lengerke-Diaz
- Department of Internal Medicine, Division of Hematology-Oncology, Mayo Clinic, Phoenix, AZ 85054, USA
| | - Daniel Achinko
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Michael Y. Choi
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
- Division of Hematology Oncology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Center for Novel Therapeutics, University of California, San Diego, La Jolla, CA 92037, USA
| | - Laura Z. Rassenti
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
- Division of Hematology Oncology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Center for Novel Therapeutics, University of California, San Diego, La Jolla, CA 92037, USA
| | - Leonardo Mariño-Ramírez
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Stephen M. Mount
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742, USA
| | - Sridhar Hannenhalli
- Cancer Data Science Lab, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Thomas J. Kipps
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
- Division of Hematology Oncology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Center for Novel Therapeutics, University of California, San Diego, La Jolla, CA 92037, USA
| | - Januario E. Castro
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
- Department of Internal Medicine, Division of Hematology-Oncology, Mayo Clinic, Phoenix, AZ 85054, USA
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3
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Zhang Q, Zhang C, Zhong H, He Q, Xia ZY, Hu Y, Liao YX, Yi L, Lu ZJ, Yu HZ. A Combinatorial Single-Molecule Real-Time and Illumina Sequencing Analysis of Postembryonic Gene Expression in the Asian Citrus Psyllid Diaphorina citri. INSECTS 2024; 15:391. [PMID: 38921106 PMCID: PMC11203772 DOI: 10.3390/insects15060391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 05/23/2024] [Accepted: 05/23/2024] [Indexed: 06/27/2024]
Abstract
Huanglongbing (HLB) is a systemic plant disease caused by 'Candidatus Liberibacter asiaticus (CLas)' and transmitted by Diaphorina citri. D. citri acquires the CLas bacteria in the nymph stage and transmits it in the adult stage, indicating that molting from the nymph to adult stages is crucial for HLB transmission. However, the available D. citri reference genomes are incomplete, and gene function studies have been limited to date. In the current research, PacBio single-molecule real-time (SMRT) and Illumina sequencing were performed to investigate the transcriptome of D. citri nymphs and adults. In total, 10,641 full-length, non-redundant transcripts (FLNRTs), 594 alternative splicing (AS) events, 4522 simple sequence repeats (SSRs), 1086 long-coding RNAs (lncRNAs), 281 transcription factors (TFs), and 4459 APA sites were identified. Furthermore, 3746 differentially expressed genes (DEGs) between nymphs and adults were identified, among which 30 DEGs involved in the Hippo signaling pathway were found. Reverse transcription-quantitative PCR (RT-qPCR) further validated the expression levels of 12 DEGs and showed a positive correlation with transcriptome data. Finally, the spatiotemporal expression pattern of genes involved in the Hippo signaling pathway exhibited high expression in the D. citri testis, ovary, and egg. Silencing of the D. citri transcriptional co-activator (DcYki) gene significantly increased D. citri mortality and decreased the cumulative molting. Our results provide useful information and a reliable data resource for gene function research of D. citri.
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Affiliation(s)
- Qin Zhang
- College of Life Sciences, Gannan Normal University, Ganzhou 341000, China; (Q.Z.); (C.Z.); (H.Z.); (Q.H.); (Z.-Y.X.); (Y.H.); (Y.-X.L.); (L.Y.); (Z.-J.L.)
| | - Can Zhang
- College of Life Sciences, Gannan Normal University, Ganzhou 341000, China; (Q.Z.); (C.Z.); (H.Z.); (Q.H.); (Z.-Y.X.); (Y.H.); (Y.-X.L.); (L.Y.); (Z.-J.L.)
| | - Hong Zhong
- College of Life Sciences, Gannan Normal University, Ganzhou 341000, China; (Q.Z.); (C.Z.); (H.Z.); (Q.H.); (Z.-Y.X.); (Y.H.); (Y.-X.L.); (L.Y.); (Z.-J.L.)
| | - Qing He
- College of Life Sciences, Gannan Normal University, Ganzhou 341000, China; (Q.Z.); (C.Z.); (H.Z.); (Q.H.); (Z.-Y.X.); (Y.H.); (Y.-X.L.); (L.Y.); (Z.-J.L.)
| | - Zhao-Ying Xia
- College of Life Sciences, Gannan Normal University, Ganzhou 341000, China; (Q.Z.); (C.Z.); (H.Z.); (Q.H.); (Z.-Y.X.); (Y.H.); (Y.-X.L.); (L.Y.); (Z.-J.L.)
| | - Yu Hu
- College of Life Sciences, Gannan Normal University, Ganzhou 341000, China; (Q.Z.); (C.Z.); (H.Z.); (Q.H.); (Z.-Y.X.); (Y.H.); (Y.-X.L.); (L.Y.); (Z.-J.L.)
| | - Yu-Xin Liao
- College of Life Sciences, Gannan Normal University, Ganzhou 341000, China; (Q.Z.); (C.Z.); (H.Z.); (Q.H.); (Z.-Y.X.); (Y.H.); (Y.-X.L.); (L.Y.); (Z.-J.L.)
| | - Long Yi
- College of Life Sciences, Gannan Normal University, Ganzhou 341000, China; (Q.Z.); (C.Z.); (H.Z.); (Q.H.); (Z.-Y.X.); (Y.H.); (Y.-X.L.); (L.Y.); (Z.-J.L.)
- National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou 341000, China
| | - Zhan-Jun Lu
- College of Life Sciences, Gannan Normal University, Ganzhou 341000, China; (Q.Z.); (C.Z.); (H.Z.); (Q.H.); (Z.-Y.X.); (Y.H.); (Y.-X.L.); (L.Y.); (Z.-J.L.)
- National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou 341000, China
| | - Hai-Zhong Yu
- College of Life Sciences, Gannan Normal University, Ganzhou 341000, China; (Q.Z.); (C.Z.); (H.Z.); (Q.H.); (Z.-Y.X.); (Y.H.); (Y.-X.L.); (L.Y.); (Z.-J.L.)
- National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou 341000, China
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4
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Sarka K, Katzman S, Zahler AM. A role for SNU66 in maintaining 5' splice site identity during spliceosome assembly. RNA (NEW YORK, N.Y.) 2024; 30:695-709. [PMID: 38443114 PMCID: PMC11098459 DOI: 10.1261/rna.079971.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 02/21/2024] [Indexed: 03/07/2024]
Abstract
In spliceosome assembly, the 5' splice site is initially recognized by U1 snRNA. U1 leaves the spliceosome during the assembly process, therefore other factors contribute to the maintenance of 5' splice site identity as it is loaded into the catalytic site. Recent structural data suggest that human tri-snRNP 27K (SNRP27) M141 and SNU66 H734 interact to stabilize the U4/U6 quasi-pseudo knot at the base of the U6 snRNA ACAGAGA box in pre-B complex. Previously, we found that mutations in Caenorhabditis elegans at SNRP-27 M141 promote changes in alternative 5'ss usage. We tested whether the potential interaction between SNRP-27 M141 and SNU-66 H765 (the C. elegans equivalent position to human SNU66 H734) contributes to maintaining 5' splice site identity during spliceosome assembly. We find that SNU-66 H765 mutants promote alternative 5' splice site usage. Many of the alternative 5' splicing events affected by SNU-66(H765G) overlap with those affected SNRP-27(M141T). Double mutants of snrp-27(M141T) and snu-66(H765G) are homozygous lethal. We hypothesize that mutations at either SNRP-27 M141 or SNU-66 H765 allow the spliceosome to load alternative 5' splice sites into the active site. Tests with mutant U1 snRNA and swapped 5' splice sites indicate that the ability of SNRP-27 M141 and SNU-66 H765 mutants to affect a particular 5' splice alternative splicing event is dependent on both the presence of a weaker consensus 5'ss nearby and potentially nearby splicing factor binding sites. Our findings confirm a new role for the C terminus of SNU-66 in maintenance of 5' splice site identity during spliceosome assembly.
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Affiliation(s)
- Kenna Sarka
- Center for Molecular Biology of RNA and Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, USA
| | - Sol Katzman
- UCSC Genomics Institute, University of California Santa Cruz, Santa Cruz, California 95064, USA
| | - Alan M Zahler
- Center for Molecular Biology of RNA and Department of Molecular, Cellular and Developmental Biology, University of California Santa Cruz, Santa Cruz, California 95064, USA
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Pabis K, Barardo D, Sirbu O, Selvarajoo K, Gruber J, Kennedy BK. A concerted increase in readthrough and intron retention drives transposon expression during aging and senescence. eLife 2024; 12:RP87811. [PMID: 38567944 PMCID: PMC10990488 DOI: 10.7554/elife.87811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024] Open
Abstract
Aging and senescence are characterized by pervasive transcriptional dysfunction, including increased expression of transposons and introns. Our aim was to elucidate mechanisms behind this increased expression. Most transposons are found within genes and introns, with a large minority being close to genes. This raises the possibility that transcriptional readthrough and intron retention are responsible for age-related changes in transposon expression rather than expression of autonomous transposons. To test this, we compiled public RNA-seq datasets from aged human fibroblasts, replicative and drug-induced senescence in human cells, and RNA-seq from aging mice and senescent mouse cells. Indeed, our reanalysis revealed a correlation between transposons expression, intron retention, and transcriptional readthrough across samples and within samples. Both intron retention and readthrough increased with aging or cellular senescence and these transcriptional defects were more pronounced in human samples as compared to those of mice. In support of a causal connection between readthrough and transposon expression, analysis of models showing induced transcriptional readthrough confirmed that they also show elevated transposon expression. Taken together, our data suggest that elevated transposon reads during aging seen in various RNA-seq dataset are concomitant with multiple transcriptional defects. Intron retention and transcriptional readthrough are the most likely explanation for the expression of transposable elements that lack a functional promoter.
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Affiliation(s)
- Kamil Pabis
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of SingaporeSingaporeSingapore
- Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of SingaporeSingaporeSingapore
- Centre for Healthy Longevity, National University Health SystemSingaporeSingapore
| | - Diogo Barardo
- Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of SingaporeSingaporeSingapore
- Centre for Healthy Longevity, National University Health SystemSingaporeSingapore
| | - Olga Sirbu
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR)SingaporeSingapore
| | - Kumar Selvarajoo
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR)SingaporeSingapore
- Singapore Institute of Food and Biotechnology Innovation, Agency for Science, Technology and Research (A*STAR)SingaporeSingapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of SingaporeSingaporeSingapore
- School of Biological Sciences, Nanyang Technological UniversitySingaporeSingapore
| | - Jan Gruber
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of SingaporeSingaporeSingapore
- Science Divisions, Yale-NUS CollegeSingaporeSingapore
| | - Brian K Kennedy
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of SingaporeSingaporeSingapore
- Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of SingaporeSingaporeSingapore
- Centre for Healthy Longevity, National University Health SystemSingaporeSingapore
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6
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Werren EA, LaForce GR, Srivastava A, Perillo DR, Li S, Johnson K, Baris S, Berger B, Regan SL, Pfennig CD, de Munnik S, Pfundt R, Hebbar M, Jimenez-Heredia R, Karakoc-Aydiner E, Ozen A, Dmytrus J, Krolo A, Corning K, Prijoles EJ, Louie RJ, Lebel RR, Le TL, Amiel J, Gordon CT, Boztug K, Girisha KM, Shukla A, Bielas SL, Schaffer AE. TREX tetramer disruption alters RNA processing necessary for corticogenesis in THOC6 Intellectual Disability Syndrome. Nat Commun 2024; 15:1640. [PMID: 38388531 PMCID: PMC10884030 DOI: 10.1038/s41467-024-45948-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Accepted: 02/07/2024] [Indexed: 02/24/2024] Open
Abstract
THOC6 variants are the genetic basis of autosomal recessive THOC6 Intellectual Disability Syndrome (TIDS). THOC6 is critical for mammalian Transcription Export complex (TREX) tetramer formation, which is composed of four six-subunit THO monomers. The TREX tetramer facilitates mammalian RNA processing, in addition to the nuclear mRNA export functions of the TREX dimer conserved through yeast. Human and mouse TIDS model systems revealed novel THOC6-dependent, species-specific TREX tetramer functions. Germline biallelic Thoc6 loss-of-function (LOF) variants result in mouse embryonic lethality. Biallelic THOC6 LOF variants reduce the binding affinity of ALYREF to THOC5 without affecting the protein expression of TREX members, implicating impaired TREX tetramer formation. Defects in RNA nuclear export functions were not detected in biallelic THOC6 LOF human neural cells. Instead, mis-splicing was detected in human and mouse neural tissue, revealing novel THOC6-mediated TREX coordination of mRNA processing. We demonstrate that THOC6 is required for key signaling pathways known to regulate the transition from proliferative to neurogenic divisions during human corticogenesis. Together, these findings implicate altered RNA processing in the developmental biology of TIDS neuropathology.
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Affiliation(s)
- Elizabeth A Werren
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
- Advanced Precision Medicine Laboratory, The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Geneva R LaForce
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Anshika Srivastava
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
- Department of Medical Genetics, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, 226014, India
| | - Delia R Perillo
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Shaokun Li
- Advanced Precision Medicine Laboratory, The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Katherine Johnson
- Advanced Precision Medicine Laboratory, The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Safa Baris
- Division of Pediatric Allergy and Immunology, School of Medicine, Marmara University, Istanbul Jeffrey Modell Diagnostic and Research Center for Primary Immunodeficiencies, The Isil Berat Barlan Center for Translational Medicine, Istanbul, 34722, Turkey
| | - Brandon Berger
- Advanced Precision Medicine Laboratory, The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Samantha L Regan
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Christian D Pfennig
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Sonja de Munnik
- Department of Human Genetics, Radboud University Medical Centre Nijmegen, Nijmegen, 6524, the Netherlands
| | - Rolph Pfundt
- Department of Human Genetics, Radboud University Medical Centre Nijmegen, Nijmegen, 6524, the Netherlands
| | - Malavika Hebbar
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, 98195, Seattle, WA, USA
| | - Raúl Jimenez-Heredia
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, 1090, Austria
| | - Elif Karakoc-Aydiner
- Division of Pediatric Allergy and Immunology, School of Medicine, Marmara University, Istanbul Jeffrey Modell Diagnostic and Research Center for Primary Immunodeficiencies, The Isil Berat Barlan Center for Translational Medicine, Istanbul, 34722, Turkey
| | - Ahmet Ozen
- Division of Pediatric Allergy and Immunology, School of Medicine, Marmara University, Istanbul Jeffrey Modell Diagnostic and Research Center for Primary Immunodeficiencies, The Isil Berat Barlan Center for Translational Medicine, Istanbul, 34722, Turkey
| | - Jasmin Dmytrus
- Research Centre for Molecular Medicine of the Austrian Academy of Sciences, Vienna, 1090, Austria
| | - Ana Krolo
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, 1090, Austria
| | - Ken Corning
- Greenwood Genetic Center, Greenwood, SC, 29646, USA
| | - E J Prijoles
- Greenwood Genetic Center, Greenwood, SC, 29646, USA
| | | | - Robert Roger Lebel
- Section of Medical Genetics, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Thuy-Linh Le
- Imagine Institute, INSERM U1163, Paris Cité University, Paris, 75015, France
| | - Jeanne Amiel
- Imagine Institute, INSERM U1163, Paris Cité University, Paris, 75015, France
- Service de Médecine Génomique des Maladies Rares, Hôpital Necker-Enfants Malades, AP-HP, Paris, 75015, France
| | | | - Kaan Boztug
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, 1090, Austria
- Research Centre for Molecular Medicine of the Austrian Academy of Sciences, Vienna, 1090, Austria
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, 1090, Austria
- St. Anna Children's Hospital and Children's Cancer Research Institute, Department of Pediatrics, Medical University of Vienna, Vienna, 1090, Austria
| | - Katta M Girisha
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, 576104, India
| | - Anju Shukla
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, 576104, India
| | - Stephanie L Bielas
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
| | - Ashleigh E Schaffer
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
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7
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Khalifah BA, Alghamdi SA, Alhasan AH. Unleashing the potential of catalytic RNAs to combat mis-spliced transcripts. Front Bioeng Biotechnol 2023; 11:1244377. [PMID: 38047291 PMCID: PMC10690607 DOI: 10.3389/fbioe.2023.1244377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 10/23/2023] [Indexed: 12/05/2023] Open
Abstract
Human transcriptome can undergo RNA mis-splicing due to spliceopathies contributing to the increasing number of genetic diseases including muscular dystrophy (MD), Alzheimer disease (AD), Huntington disease (HD), myelodysplastic syndromes (MDS). Intron retention (IR) is a major inducer of spliceopathies where two or more introns remain in the final mature mRNA and account for many intronic expansion diseases. Potential removal of such introns for therapeutic purposes can be feasible when utilizing bioinformatics, catalytic RNAs, and nano-drug delivery systems. Overcoming delivery challenges of catalytic RNAs was discussed in this review as a future perspective highlighting the significance of utilizing synthetic biology in addition to high throughput deep sequencing and computational approaches for the treatment of mis-spliced transcripts.
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Affiliation(s)
- Bashayer A. Khalifah
- Institute for Bioengineering, Health Sector, King Abdulaziz City for Science and Technology (KACST), Riyadh, Saudi Arabia
- Faculty of Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | | | - Ali H. Alhasan
- Institute for Bioengineering, Health Sector, King Abdulaziz City for Science and Technology (KACST), Riyadh, Saudi Arabia
- College of Science and General Studies, Alfaisal University, Riyadh, Saudi Arabia
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8
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Theil AF, Pines A, Kalayci T, Heredia‐Genestar JM, Raams A, Rietveld MH, Sridharan S, Tanis SEJ, Mulder KW, Büyükbabani N, Karaman B, Uyguner ZO, Kayserili H, Hoeijmakers JHJ, Lans H, Demmers JAA, Pothof J, Altunoglu U, El Ghalbzouri A, Vermeulen W. Trichothiodystrophy-associated MPLKIP maintains DBR1 levels for proper lariat debranching and ectodermal differentiation. EMBO Mol Med 2023; 15:e17973. [PMID: 37800682 PMCID: PMC10630875 DOI: 10.15252/emmm.202317973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 10/07/2023] Open
Abstract
The brittle hair syndrome Trichothiodystrophy (TTD) is characterized by variable clinical features, including photosensitivity, ichthyosis, growth retardation, microcephaly, intellectual disability, hypogonadism, and anaemia. TTD-associated mutations typically cause unstable mutant proteins involved in various steps of gene expression, severely reducing steady-state mutant protein levels. However, to date, no such link to instability of gene-expression factors for TTD-associated mutations in MPLKIP/TTDN1 has been established. Here, we present seven additional TTD individuals with MPLKIP mutations from five consanguineous families, with a newly identified MPLKIP variant in one family. By mass spectrometry-based interaction proteomics, we demonstrate that MPLKIP interacts with core splicing factors and the lariat debranching protein DBR1. MPLKIP-deficient primary fibroblasts have reduced steady-state DBR1 protein levels. Using Human Skin Equivalents (HSEs), we observed impaired keratinocyte differentiation associated with compromised splicing and eventually, an imbalanced proteome affecting skin development and, interestingly, also the immune system. Our data show that MPLKIP, through its DBR1 stabilizing role, is implicated in mRNA splicing, which is of particular importance in highly differentiated tissue.
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Affiliation(s)
- Arjan F Theil
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
| | - Alex Pines
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
| | - Tuğba Kalayci
- Department of Medical Genetics, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
| | | | - Anja Raams
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
| | - Marion H Rietveld
- Department of DermatologyLeiden University Medical Center (LUMC)LeidenThe Netherlands
| | - Sriram Sridharan
- Cancer Science Institute of SingaporeNational University of SingaporeSingaporeSingapore
| | - Sabine EJ Tanis
- Department of Molecular Developmental Biology, Faculty of Science, Radboud Institute for Molecular Life SciencesRadboud UniversityNijmegenThe Netherlands
| | - Klaas W Mulder
- Department of Molecular Developmental Biology, Faculty of Science, Radboud Institute for Molecular Life SciencesRadboud UniversityNijmegenThe Netherlands
| | - Nesimi Büyükbabani
- Department of Pathology, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
- Department of Medical GeneticsKoc University HospitalIstanbulTurkey
| | - Birsen Karaman
- Department of Medical Genetics, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
- Department of Pediatric Basic Sciences, Child Health InstituteIstanbul UniversityIstanbulTurkey
| | - Zehra O Uyguner
- Department of Medical Genetics, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
| | - Hülya Kayserili
- Department of Medical Genetics, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
- Department of Medical GeneticsKoc University School of Medicine (KUSOM)IstanbulTurkey
| | - Jan HJ Hoeijmakers
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
- Institute for Genome Stability in Aging and Disease, CECAD ForschungszentrumUniversity Hospital of CologneKölnGermany
- Princess Máxima Center for Pediatric OncologyONCODE InstituteUtrechtThe Netherlands
| | - Hannes Lans
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
| | | | - Joris Pothof
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
| | - Umut Altunoglu
- Department of Medical Genetics, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
- Department of Medical GeneticsKoc University School of Medicine (KUSOM)IstanbulTurkey
| | | | - Wim Vermeulen
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
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9
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Su T, Hollas MAR, Fellers RT, Kelleher NL. Identification of Splice Variants and Isoforms in Transcriptomics and Proteomics. Annu Rev Biomed Data Sci 2023; 6:357-376. [PMID: 37561601 PMCID: PMC10840079 DOI: 10.1146/annurev-biodatasci-020722-044021] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Alternative splicing is pivotal to the regulation of gene expression and protein diversity in eukaryotic cells. The detection of alternative splicing events requires specific omics technologies. Although short-read RNA sequencing has successfully supported a plethora of investigations on alternative splicing, the emerging technologies of long-read RNA sequencing and top-down mass spectrometry open new opportunities to identify alternative splicing and protein isoforms with less ambiguity. Here, we summarize improvements in short-read RNA sequencing for alternative splicing analysis, including percent splicing index estimation and differential analysis. We also review the computational methods used in top-down proteomics analysis regarding proteoform identification, including the construction of databases of protein isoforms and statistical analyses of search results. While many improvements in sequencing and computational methods will result from emerging technologies, there should be future endeavors to increase the effectiveness, integration, and proteome coverage of alternative splicing events.
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Affiliation(s)
- Taojunfeng Su
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, USA;
| | - Michael A R Hollas
- Proteomics Center of Excellence, Northwestern University, Evanston, Illinois, USA
| | - Ryan T Fellers
- Proteomics Center of Excellence, Northwestern University, Evanston, Illinois, USA
| | - Neil L Kelleher
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, USA;
- Proteomics Center of Excellence, Northwestern University, Evanston, Illinois, USA
- Department of Chemistry, Northwestern University, Evanston, Illinois, USA
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10
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Sun X, Liu Z, Li Z, Zeng Z, Peng W, Zhu J, Zhao J, Zhu C, Zeng C, Stearrett N, Crandall KA, Bachali P, Grammer AC, Lipsky PE. Abnormalities in intron retention characterize patients with systemic lupus erythematosus. Sci Rep 2023; 13:5141. [PMID: 36991079 PMCID: PMC10060252 DOI: 10.1038/s41598-023-31890-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 03/20/2023] [Indexed: 03/31/2023] Open
Abstract
Regulation of intron retention (IR), a form of alternative splicing, is a newly recognized checkpoint in gene expression. Since there are numerous abnormalities in gene expression in the prototypic autoimmune disease systemic lupus erythematosus (SLE), we sought to determine whether IR was intact in patients with this disease. We, therefore, studied global gene expression and IR patterns of lymphocytes in SLE patients. We analyzed RNA-seq data from peripheral blood T cell samples from 14 patients suffering from systemic lupus erythematosus (SLE) and 4 healthy controls and a second, independent data set of RNA-seq data from B cells from16 SLE patients and 4 healthy controls. We identified intron retention levels from 26,372 well annotated genes as well as differential gene expression and tested for differences between cases and controls using unbiased hierarchical clustering and principal component analysis. We followed with gene-disease enrichment analysis and gene-ontology enrichment analysis. Finally, we then tested for significant differences in intron retention between cases and controls both globally and with respect to specific genes. Overall decreased IR was found in T cells from one cohort and B cells from another cohort of patients with SLE and was associated with increased expression of numerous genes, including those encoding spliceosome components. Different introns within the same gene displayed both up- and down-regulated retention profiles indicating a complex regulatory mechanism. These results indicate that decreased IR in immune cells is characteristic of patients with active SLE and may contribute to the abnormal expression of specific genes in this autoimmune disease.
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Affiliation(s)
- Xiaoqian Sun
- Computer Science Department, George Washington University, Washington, DC, 20052, USA
| | - Zhichao Liu
- Physics Department, George Washington University, Washington, DC, 20052, USA
| | - Zongzhu Li
- Physics Department, George Washington University, Washington, DC, 20052, USA
| | - Zhouhao Zeng
- Physics Department, George Washington University, Washington, DC, 20052, USA
| | - Weiqun Peng
- Physics Department, George Washington University, Washington, DC, 20052, USA
| | - Jun Zhu
- Mokobio Biotechnology R&D Center, 1445 Research Blvd, Suite 150, Rockville, MD, 20850, USA
| | - Joel Zhao
- Walt Whitman High School, Bethesda, MD, 20817, USA
| | | | - Chen Zeng
- Physics Department, George Washington University, Washington, DC, 20052, USA.
| | - Nathaniel Stearrett
- Computational Biology Institute, Milken Institute School of Public Health, George Washington University, Washington, DC, 20052, USA
| | - Keith A Crandall
- Computational Biology Institute, Milken Institute School of Public Health, George Washington University, Washington, DC, 20052, USA.
| | - Prathyusha Bachali
- RILITE Research Institute and AMPEL BioSolutions, 250 W Main St, Ste 300, Charlottesville, VA, 22902, USA
| | - Amrie C Grammer
- RILITE Research Institute and AMPEL BioSolutions, 250 W Main St, Ste 300, Charlottesville, VA, 22902, USA
| | - Peter E Lipsky
- RILITE Research Institute and AMPEL BioSolutions, 250 W Main St, Ste 300, Charlottesville, VA, 22902, USA.
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11
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Rashad S, Byrne SR, Saigusa D, Xiang J, Zhou Y, Zhang L, Begley TJ, Tominaga T, Niizuma K. Codon Usage and mRNA Stability are Translational Determinants of Cellular Response to Canonical Ferroptosis Inducers. Neuroscience 2022; 501:103-130. [PMID: 35987429 PMCID: PMC10023133 DOI: 10.1016/j.neuroscience.2022.08.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 08/02/2022] [Accepted: 08/08/2022] [Indexed: 11/29/2022]
Abstract
Ferroptosis is a non-apoptotic cell death mechanism characterized by the generation of lipid peroxides. While many effectors in the ferroptosis pathway have been mapped, its epitranscriptional regulation is not yet fully understood. Ferroptosis can be induced via system xCT inhibition (Class I) or GPX4 inhibition (Class II). Previous works have revealed important differences in cellular response to different ferroptosis inducers. Importantly, blocking mRNA transcription or translation appears to protect cells against Class I ferroptosis inducing agents but not Class II. In this work, we examined the impact of blocking transcription (via Actinomycin D) or translation (via Cycloheximide) on Erastin (Class I) or RSL3 (Class II) induced ferroptosis. Blocking transcription or translation protected cells against Erastin but was detrimental against RSL3. Cycloheximide led to increased levels of GSH alone or when co-treated with Erastin via the activation of the reverse transsulfuration pathway. RNA sequencing analysis revealed early activation of a strong alternative splice program before observed changes in transcription. mRNA stability analysis revealed divergent mRNA stability changes in cellular response to Erastin or RSL3. Importantly, codon optimality biases were drastically different in either condition. Our data also implicated translation repression and rate as an important determinant of the cellular response to ferroptosis inducers. Given that mRNA stability and codon usage can be influenced via the tRNA epitranscriptome, we evaluated the role of a tRNA modifying enzyme in ferroptosis stress response. Alkbh1, a tRNA demethylase, led to translation repression and increased the resistance to Erastin but made cells more sensitive to RSL3.
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Affiliation(s)
- Sherif Rashad
- Department of Neurosurgical Engineering and Translational Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Neurosurgical Engineering and Translational Neuroscience, Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan; Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Japan.
| | - Shane R Byrne
- Department of Biological Engineering and Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Daisuke Saigusa
- Laboratory of Biomedical and Analytical Sciences, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan; Department of Integrative Genomics, Tohoku University Medical Megabank Organization, Sendai, Japan
| | - Jingdong Xiang
- Department of Biological Engineering and Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yuan Zhou
- Department of Neurosurgical Engineering and Translational Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Liyin Zhang
- Department of Neurosurgical Engineering and Translational Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Thomas J Begley
- The RNA Institute, University at Albany, Albany, NY, USA; Department of Biological Sciences, University at Albany, Albany, NY, USA; RNA Epitranscriptomics and Proteomics Resource, University at Albany, Albany, NY, USA
| | - Teiji Tominaga
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kuniyasu Niizuma
- Department of Neurosurgical Engineering and Translational Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Neurosurgical Engineering and Translational Neuroscience, Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan; Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Japan
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12
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de Obeso Fernández Del Valle A, Gómez-Montalvo J, Maciver SK. Acanthamoeba castellanii exhibits intron retention during encystment. Parasitol Res 2022; 121:2615-2622. [PMID: 35776211 DOI: 10.1007/s00436-022-07578-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 06/14/2022] [Indexed: 11/24/2022]
Abstract
Intron retention (IR) refers to the mechanism of alternative splicing in which an intron is not excised from the mature transcript. IR in the cosmopolitan free-living amoeba Acanthamoeba castellanii has not been studied. We performed an analysis of RNA sequencing data during encystment to identify genes that presented differentially retained introns during this process. We show that IR increases during cyst formation, indicating a potential mechanism of gene regulation that could help downregulate metabolism. We identify 69 introns from 67 genes that are differentially retained comparing the trophozoite stage and encystment after 24 and 48 h. These genes include several hypothetical proteins. We show different patterns of IR during encystment taking as examples a lipase, a peroxin-3 protein, an Fbox domain containing protein, a proteasome subunit, a polynucleotide adenylyltransferase, and a tetratricopeptide domain containing protein. A better understanding of IR in Acanthamoeba, and even other protists, could help elucidate changes in life cycle and combat disease such as Acanthamoeba keratitis in which the cyst is key for its persistence.
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Affiliation(s)
- Alvaro de Obeso Fernández Del Valle
- Departamento de Bioingeniería, Escuela de Ingeniería y Ciencias, Tecnologico de Monterrey, Ave. Eugenio Garza Sada 2501, 64849, Monterrey, Mexico.
| | - Jesús Gómez-Montalvo
- Departamento de Bioingeniería, Escuela de Ingeniería y Ciencias, Tecnologico de Monterrey, Ave. Eugenio Garza Sada 2501, 64849, Monterrey, Mexico
| | - Sutherland K Maciver
- Centre for Discovery Brain Sciences, Edinburgh Medical School, Biomedical Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, Scotland, UK
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13
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RNA splicing: a dual-edged sword for hepatocellular carcinoma. MEDICAL ONCOLOGY (NORTHWOOD, LONDON, ENGLAND) 2022; 39:173. [PMID: 35972700 DOI: 10.1007/s12032-022-01726-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 03/30/2022] [Indexed: 10/15/2022]
Abstract
RNA splicing is the fundamental process that brings diversity at the transcriptome and proteome levels. The spliceosome complex regulates minor and major processes of RNA splicing. Aberrant regulation is often associated with different diseases, including diabetes, stroke, hypertension, and cancer. In the majority of cancers, dysregulated alternative RNA splicing (ARS) events directly affect tumor progression, invasiveness, and often lead to poor survival of the patients. Alike the rest of the gastrointestinal malignancies, in hepatocellular carcinoma (HCC), which alone contributes to ~ 75% of the liver cancers, a large number of ARS events have been observed, including intron retention, exon skipping, presence of alternative 3'-splice site (3'SS), and alternative 5'-splice site (5'SS). These events are reported in spliceosome and non-spliceosome complexes genes. Molecules such as MCL1, Bcl-X, and BCL2 in different isoforms can behave as anti-apoptotic or pro-apoptotic, making the spliceosome complex a dual-edged sword. The anti-apoptotic isoforms of such molecules bring in resistance to chemotherapy or cornerstone drugs. However, in contrast, multiple malignant tumors, including HCC that target the pro-apoptotic favoring isoforms/variants favor apoptotic induction and make chemotherapy effective. Herein, we discuss different splicing events, aberrations, and antisense oligonucleotides (ASOs) in modulating RNA splicing in HCC tumorigenesis with a possible therapeutic outcome.
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14
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Massri M, Foco L, Würzner R. Comprehensive Update and Revision of Nomenclature on Complement C6 and C7 Variants. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:2597-2612. [PMID: 35867677 DOI: 10.4049/jimmunol.2200045] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 04/11/2022] [Indexed: 06/15/2023]
Abstract
Complement genes encompass a wide array of variants, giving rise to numerous protein isoforms that have often been shown to exhibit clinical significance. Given that these variants have been discovered over a span of 50 y, one challenging consequence is the inconsistency in the terminology used to classify them. This issue is prominently evident in the nomenclature used for complement C6 and C7 variants, for which we observed a great discrepancy between previously published works and variants described in current genome browsers. This report discusses the causes for the discrepancies in C6 and C7 nomenclature and seeks to establish a classification system that would unify existing and future variants. The inconsistency in the methods used to annotate amino acids and the modifications pinpointed in the C6 and C7 primers are some of the factors that contribute greatly to the discrepancy in the nomenclature. Several variants that were classified incorrectly are highlighted in this report, and we showcase first-hand how a unified classification system is important to match previous with current genetic information. Ultimately, we hope that the proposed classification system of nomenclature becomes an incentive for studies on complement variants and their physiological and/or pathological effects.
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Affiliation(s)
- Mariam Massri
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria; and
| | - Luisa Foco
- Institute for Biomedicine (affiliated with the University of Lübeck), Eurac Research, Bolzano, Italy
| | - Reinhard Würzner
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria; and
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15
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Meta-Analysis Suggests That Intron Retention Can Affect Quantification of Transposable Elements from RNA-Seq Data. BIOLOGY 2022; 11:biology11060826. [PMID: 35741347 PMCID: PMC9220773 DOI: 10.3390/biology11060826] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/20/2022] [Accepted: 05/26/2022] [Indexed: 02/08/2023]
Abstract
Simple Summary Transposable elements (TEs) are repetitive sequences comprising more than one third of the human genome with the original ability to change their location within the genome. Owing to their repetitive nature, the quantification of TEs results often challenging. RNA-seq is a useful tool for genome-wide TEs quantification, nevertheless it also presents technical issues, including low reads mappability and erroneous quantification derived from the transcription of TEs fragments embedded in canonical transcripts. Fragments derived from TEs are found within the introns of most genes, which led to the hypothesis that intron retention (IR) can affect the unbiased quantification of TEs expression. Performing meta-analysis of public RNA-seq datasets, here we observe that IR can indeed impact the quantification of TEs by increasing the number of reads mapped on intronic TE copies. Our work highlights a correlation between IR and TEs expression measurement by RNA-seq that should be taken into account to achieve reliable TEs quantification, especially in samples characterized by extensive IR, because differential IR might be confused with differential TEs expression. Abstract Transposable elements (TEs), also known as “jumping genes”, are repetitive sequences with the capability of changing their location within the genome. They are key players in many different biological processes in health and disease. Therefore, a reliable quantification of their expression as transcriptional units is crucial to distinguish between their independent expression and the transcription of their sequences as part of canonical transcripts. TEs quantification faces difficulties of different types, the most important one being low reads mappability due to their repetitive nature preventing an unambiguous mapping of reads originating from their sequences. A large fraction of TEs fragments localizes within introns, which led to the hypothesis that intron retention (IR) can be an additional source of bias, potentially affecting accurate TEs quantification. IR occurs when introns, normally removed from the mature transcript by the splicing machinery, are maintained in mature transcripts. IR is a widespread mechanism affecting many different genes with cell type-specific patterns. We hypothesized that, in an RNA-seq experiment, reads derived from retained introns can introduce a bias in the detection of overlapping, independent TEs RNA expression. In this study we performed meta-analysis using public RNA-seq data from lymphoblastoid cell lines and show that IR can impact TEs quantification using established tools with default parameters. Reads mapped on intronic TEs were indeed associated to the expression of TEs and influence their correct quantification as independent transcriptional units. We confirmed these results using additional independent datasets, demonstrating that this bias does not appear in samples where IR is not present and that differential TEs expression does not impact on IR quantification. We concluded that IR causes the over-quantification of intronic TEs and differential IR might be confused with differential TEs expression. Our results should be taken into account for a correct quantification of TEs expression from RNA-seq data, especially in samples in which IR is abundant.
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16
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Xiao P, Goodarzi P, Pezeshki A, Hagen DE. RNA-seq reveals insights into molecular mechanisms of metabolic restoration via tryptophan supplementation in low birthweight piglet model. J Anim Sci 2022; 100:6584466. [PMID: 35552417 PMCID: PMC9155244 DOI: 10.1093/jas/skac156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 04/26/2022] [Indexed: 11/23/2022] Open
Abstract
Low birth weight (LBW) is associated with metabolic disorders in early life. While dietary l-tryptophan (Trp) can ameliorate postprandial plasma triglycerides (TG) disposal in LBW piglets, the genetic and biological basis underlying Trp-caused alterations in lipid metabolism is poorly understood. In this study, we collected 24 liver samples from 1-mo-old LBW and normal birth weight (NBW) piglets supplemented with different concentrations of dietary Trp (NBW with 0% Trp, N0; LBW with 0% Trp, L0; LBW with 0.4% Trp, L4; LBW with 0.8% Trp, L8; N = 6 in each group.) and conducted systematic, transcriptome-wide analysis using RNA sequencing (RNA-seq). We identified 39 differentially expressed genes (DEG) between N0 and L0, and genes within “increased dose effect” clusters based on dose-series expression profile analysis, enriched in fatty acid response of gene ontology (GO) biological process (BP). We then identified RNA-binding proteins including SRSF1, DAZAP1, PUM2, PCBP3, IGF2BP2, and IGF2BP3 significantly (P < 0.05) enriched in alternative splicing events (ASE) in comparison with L0 as control. There were significant positive and negative relationships between candidate genes from co-expression networks (including PID1, ANKRD44, RUSC1, and CYP2J34) and postprandial plasma TG concentration. Further, we determined whether these candidate hub genes were also significantly associated with metabolic and cardiovascular traits in humans via human phenome-wide association study (Phe-WAS), and analysis of mammalian orthologs suggests a functional conservation between human and pig. Our work demonstrates that transcriptomic changes during dietary Trp supplementation in LBW piglets. We detected candidate genes and related BP that may play roles on lipid metabolism restoration. These findings will help to better understand the amino acid support in LBW metabolic complications.
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Affiliation(s)
- Ping Xiao
- Department of Animal and Food Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - Parniyan Goodarzi
- Department of Animal and Food Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - Adel Pezeshki
- Department of Animal and Food Sciences, Oklahoma State University, Stillwater, OK 74078, USA
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17
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Park J, Kim D, Lee JO, Park HC, Ryu BY, Kim JH, Lee SH, Chung YJ. Dissection of molecular and histological subtypes of papillary thyroid cancer using alternative splicing profiles. Exp Mol Med 2022; 54:263-272. [PMID: 35277656 PMCID: PMC8980103 DOI: 10.1038/s12276-022-00740-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/10/2021] [Accepted: 12/27/2021] [Indexed: 12/01/2022] Open
Abstract
Despite growing evidence of the relevance of alternative splicing (AS) to cancer development and progression, the biological implications of AS for tumor behaviors, including papillary thyroid cancer (PTC), remain elusive. With the aim of further understanding the molecular and histological subtypes of PTC, we in this study explored whether AS events might act as new molecular determinants. For this purpose, AS profiles were analyzed in RNA-sequencing data from The Cancer Genome Atlas (TCGA) and from a Korean patient dataset. A total of 23 distinct exon-skipping (ES) events that correlated significantly with PTC oncogenic activity and differentiation scores were identified. The two top-ranked ES events, NUMA1_17515 in exon 18 of NUMA1 and TUBB3_38175 in exon 6 of TUBB3, showed high correlations with oncogenic activities and discriminated histological and molecular subtypes of PTC. Furthermore, two novel intron-retention (IR) events for TUBB3 were uncovered. All ES and IR events for the TUBB3 gene were predicted to induce nonsense-mediated mRNA decay. The relative abundances of intron reads in the PTC dataset from TCGA showed IR levels to differ significantly among PTC subtypes, possibly reflecting their different tumor behaviors. This study provides a landscape of AS changes among PTC subtypes and identified two significant AS events, NUMA1_17515 and TUBB3_38175, as potential AS biomarkers for PTC subclassification and characterization. The AS events identified in this study may be involved in the development of phenotypic differences underlying the functional characteristics and histological differentiation of PTCs. Two potential biomarkers uncovered by scientists in South Korea may help more accurately classify subtypes of papillary thyroid cancer, the most common form of thyroid cancer, and improve treatment regimens. Ascertaining the correct papillary thyroid cancer (PTC) subtype is important for patient prognoses and treatment plans. Growing evidence suggests that cancer progression may be influenced by ‘alternative splicing’ events, alterations to mRNA that change the structure of mRNA transcripts and affect the function of encoded proteins. Yeun-Jun Chung and Sug Hyung Lee at the Catholic University of Korea, Seoul, and co-workers explored alternative splicing events in PTC patient samples. They identified 25 distinct events associated with oncogenic activity and differentiation between PTC subtypes. Of these, two events associated with two separate genes are particularly significant and could prove useful as biomarkers for disease classification and characterisation.
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Affiliation(s)
- Jiyeon Park
- Precision Medicine Research Center, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Integrated Research Center for Genome Polymorphism, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Department of Biomedicine & Health Sciences, Graduate School, The Catholic University of Korea, Seoul, Republic of Korea
| | - Dongmoung Kim
- Precision Medicine Research Center, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Department of Biomedicine & Health Sciences, Graduate School, The Catholic University of Korea, Seoul, Republic of Korea
| | - Jin-Ok Lee
- Department of Biomedicine & Health Sciences, Graduate School, The Catholic University of Korea, Seoul, Republic of Korea
| | - Hyeon-Chun Park
- Department of Microbiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Brian Y Ryu
- Seoul National University Biomedical Informatics, Division of Biomedical Informatics, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ju Han Kim
- Seoul National University Biomedical Informatics, Division of Biomedical Informatics, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Sug Hyung Lee
- Department of Pathology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
| | - Yeun-Jun Chung
- Precision Medicine Research Center, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea. .,Integrated Research Center for Genome Polymorphism, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea. .,Department of Microbiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
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18
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Tommasi S, Kitapci TH, Blumenfeld H, Besaratinia A. Secondhand smoke affects reproductive functions by altering the mouse testis transcriptome, and leads to select intron retention in Pde1a. ENVIRONMENT INTERNATIONAL 2022; 161:107086. [PMID: 35063792 PMCID: PMC8891074 DOI: 10.1016/j.envint.2022.107086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 12/20/2021] [Accepted: 01/07/2022] [Indexed: 05/13/2023]
Abstract
BACKGROUND Human exposure to secondhand smoke (SHS) is known to result in adverse effects in multiple organ systems. However, the impact of SHS on the male reproductive system, particularly on the regulation of genes and molecular pathways that govern sperm production, maturation, and functions remains largely understudied. OBJECTIVE We investigated the effects of SHS on the testis transcriptome in a validated mouse model. METHODS Adult male mice were exposed to SHS (5 h/day, 5 days/week for 4 months) as compared to controls (clean air-exposed). RNA-seq analysis was performed on the testis of SHS-exposed mice and controls. Variant discovery and plink association analyses were also conducted to detect exposure-related transcript variants in SHS-treated mice. RESULTS Exposure of mice to SHS resulted in the aberrant expression of 131 testicular genes. Whilst approximately two thirds of the differentially expressed genes were protein-coding, the remaining (30.5%) comprised noncoding elements, mostly lncRNAs (19.1%). Variant discovery analysis identified a homozygous frameshift variant that is statistically significantly associated with SHS exposure (P = 7.744e-06) and is generated by retention of a short intron within Pde1a, a key regulator of spermatogenesis. Notably, this SHS-associated intron variant harbors an evolutionarily conserved, premature termination codon (PTC) that disrupts the open reading frame of Pde1a, presumably leading to its degradation via nonsense-mediated decay. DISCUSSION SHS alters the expression of genes involved in molecular pathways that are crucial for normal testis development and function. Preferential targeting of lncRNAs in the testis of SHS-exposed mice is especially significant considering their crucial role in the spatial and temporal modulation of spermatogenesis. Equally important is our discovery of a novel homozygous frameshift variant that is exclusively and significantly associated with SHS-exposure and is likely to represent a safeguard mechanism to regulate transcription of Pde1a and preserve normal testis function during harmful exposure to environmental agents.
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Affiliation(s)
- Stella Tommasi
- Department of Population and Public Health Sciences, USC Keck School of Medicine, University of Southern California, M/C 9603, Los Angeles, CA 90033, USA.
| | - Tevfik H Kitapci
- Department of Population and Public Health Sciences, USC Keck School of Medicine, University of Southern California, M/C 9603, Los Angeles, CA 90033, USA
| | - Hannah Blumenfeld
- Department of Population and Public Health Sciences, USC Keck School of Medicine, University of Southern California, M/C 9603, Los Angeles, CA 90033, USA
| | - Ahmad Besaratinia
- Department of Population and Public Health Sciences, USC Keck School of Medicine, University of Southern California, M/C 9603, Los Angeles, CA 90033, USA
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19
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Salabi F, Jafari H. New insights about scorpion venom hyaluronidase; isoforms, expression and phylogeny. TOXIN REV 2022. [DOI: 10.1080/15569543.2021.2018613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Fatemeh Salabi
- Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Ahvaz, Iran
| | - Hedieh Jafari
- Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Ahvaz, Iran
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20
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Ebrahimie E, Rahimirad S, Tahsili M, Mohammadi-Dehcheshmeh M. Alternative RNA splicing in stem cells and cancer stem cells: Importance of transcript-based expression analysis. World J Stem Cells 2021; 13:1394-1416. [PMID: 34786151 PMCID: PMC8567453 DOI: 10.4252/wjsc.v13.i10.1394] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/21/2021] [Accepted: 09/14/2021] [Indexed: 02/06/2023] Open
Abstract
Alternative ribonucleic acid (RNA) splicing can lead to the assembly of different protein isoforms with distinctive functions. The outcome of alternative splicing (AS) can result in a complete loss of function or the acquisition of new functions. There is a gap in knowledge of abnormal RNA splice variants promoting cancer stem cells (CSCs), and their prospective contribution in cancer progression. AS directly regulates the self-renewal features of stem cells (SCs) and stem-like cancer cells. Notably, octamer-binding transcription factor 4A spliced variant of octamer-binding transcription factor 4 contributes to maintaining stemness properties in both SCs and CSCs. The epithelial to mesenchymal transition pathway regulates the AS events in CSCs to maintain stemness. The alternative spliced variants of CSCs markers, including cluster of differentiation 44, aldehyde dehydrogenase, and doublecortin-like kinase, α6β1 integrin, have pivotal roles in increasing self-renewal properties and maintaining the pluripotency of CSCs. Various splicing analysis tools are considered in this study. LeafCutter software can be considered as the best tool for differential splicing analysis and identification of the type of splicing events. Additionally, LeafCutter can be used for efficient mapping splicing quantitative trait loci. Altogether, the accumulating evidence re-enforces the fact that gene and protein expression need to be investigated in parallel with alternative splice variants.
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Affiliation(s)
- Esmaeil Ebrahimie
- School of Animal and Veterinary Sciences, The University of Adelaide, Adelaide 5005, South Australia, Australia
- La Trobe Genomics Research Platform, School of Life Sciences, College of Science, Health and Engineering, La Trobe University, Melbourne 3086, Australia
- School of Biosciences, The University of Melbourne, Melbourne 3010, Australia,
| | - Samira Rahimirad
- Department of Medical Genetics, National Institute of Genetic Engineering and Biotechnology, Tehran 1497716316, Iran
- Division of Urology, Department of Surgery, McGill University and the Research Institute of the McGill University Health Centre, Montreal H4A 3J1, Quebec, Canada
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21
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Dey P, Mattick JS. High frequency of intron retention and clustered H3K4me3-marked nucleosomes in short first introns of human long non-coding RNAs. Epigenetics Chromatin 2021; 14:45. [PMID: 34579770 PMCID: PMC8477579 DOI: 10.1186/s13072-021-00419-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 08/27/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND It is established that protein-coding exons are preferentially localized in nucleosomes. To examine whether the same is true for non-coding exons, we analysed nucleosome occupancy in and adjacent to internal exons in genes encoding long non-coding RNAs (lncRNAs) in human CD4+ T cells and K562 cells. RESULTS We confirmed that internal exons in lncRNAs are preferentially associated with nucleosomes, but also observed an elevated signal from H3K4me3-marked nucleosomes in the sequences upstream of these exons. Examination of 200 genomic lncRNA loci chosen at random across all chromosomes showed that high-density regions of H3K4me3-marked nucleosomes, which we term 'slabs', are associated with genomic regions exhibiting intron retention. These retained introns occur in over 50% of lncRNAs examined and are mostly first introns with an average length of just 354 bp, compared to the average length of all human introns of 6355 and 7987 bp in mRNAs and lncRNAs, respectively. Removal of short introns from the dataset abrogated the high upstream H3K4me3 signal, confirming that the association of slabs and short lncRNA introns with intron retention holds genome-wide. The high upstream H3K4me3 signal is also associated with alternatively spliced exons, known to be prominent in lncRNAs. This phenomenon was not observed with mRNAs. CONCLUSIONS There is widespread intron retention and clustered H3K4me3-marked nucleosomes in short first introns of human long non-coding RNAs, which raises intriguing questions about the relationship of IR to lncRNA function and chromatin organization.
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Affiliation(s)
- Pinki Dey
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, 2052, Sydney, Australia
| | - John S Mattick
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, 2052, Sydney, Australia.
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22
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Riolo G, Cantara S, Ricci C. What's Wrong in a Jump? Prediction and Validation of Splice Site Variants. Methods Protoc 2021; 4:62. [PMID: 34564308 PMCID: PMC8482176 DOI: 10.3390/mps4030062] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 08/27/2021] [Accepted: 09/03/2021] [Indexed: 02/07/2023] Open
Abstract
Alternative splicing (AS) is a crucial process to enhance gene expression driving organism development. Interestingly, more than 95% of human genes undergo AS, producing multiple protein isoforms from the same transcript. Any alteration (e.g., nucleotide substitutions, insertions, and deletions) involving consensus splicing regulatory sequences in a specific gene may result in the production of aberrant and not properly working proteins. In this review, we introduce the key steps of splicing mechanism and describe all different types of genomic variants affecting this process (splicing variants in acceptor/donor sites or branch point or polypyrimidine tract, exonic, and deep intronic changes). Then, we provide an updated approach to improve splice variants detection. First, we review the main computational tools, including the recent Machine Learning-based algorithms, for the prediction of splice site variants, in order to characterize how a genomic variant interferes with splicing process. Next, we report the experimental methods to validate the predictive analyses are defined, distinguishing between methods testing RNA (transcriptomics analysis) or proteins (proteomics experiments). For both prediction and validation steps, benefits and weaknesses of each tool/procedure are accurately reported, as well as suggestions on which approaches are more suitable in diagnostic rather than in clinical research.
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Affiliation(s)
| | | | - Claudia Ricci
- Department of Medical, Surgical and Neurological Sciences, University of Siena, 53100 Siena, Italy; (G.R.); (S.C.)
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23
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He C, Guo J, Tian W, Wong CCL. Proteogenomics Integrating Novel Junction Peptide Identification Strategy Discovers Three Novel Protein Isoforms of Human NHSL1 and EEF1B2. J Proteome Res 2021; 20:5294-5303. [PMID: 34420305 DOI: 10.1021/acs.jproteome.1c00373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In eukaryotes, alternative pre-mRNA splicing allows a single gene to encode different protein isoforms that function in many biological processes, and they are used as biomarkers or therapeutic targets for diseases. Although protein isoforms in the human genome are well annotated, we speculate that some low-abundance protein isoforms may still be under-annotated because most genes have a primary coding product and alternative protein isoforms tend to be under-expressed. A peptide coencoded by a novel exon and an annotated exon separated by an intron is known as a novel junction peptide. In the absence of known transcripts and homologous proteins, traditional whole-genome six-frame translation-based proteogenomics cannot identify novel junction peptides, and it cannot capture novel alternative splice sites. In this article, we first propose a strategy and tool for identifying novel junction peptides, called CJunction, which we then integrate into a proteogenomics process specifically designed for novel protein isoform discovery and apply to the analysis of a deep-coverage HeLa mass spectrometry data set with identifier PXD004452 in ProteomeXchange. We succeeded in identifying and validating three novel protein isoforms of two functionally important genes, NHSL1 (causative gene of Nance-Horan syndrome) and EEF1B2 (translation elongation factor), which validate our hypothesis. These novel protein isoforms have significant sequence differences from the annotated gene-coding products introduced by the novel N-terminal, suggesting that they may play importantly different functions.
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Affiliation(s)
- Cuitong He
- Peking-Tsinghua Centre for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, 100871 Beijing, China.,Center for Precision Medicine Multi-Omics Research, Peking University Health Science Center, 100191 Beijing, China
| | - Jiangtao Guo
- Center for Precision Medicine Multi-Omics Research, Peking University Health Science Center, 100191 Beijing, China
| | - Wenmin Tian
- Center for Precision Medicine Multi-Omics Research, Peking University Health Science Center, 100191 Beijing, China.,School of Basic Medical Sciences, Peking University Health Science Center, 100191 Beijing, China
| | - Catherine C L Wong
- Peking-Tsinghua Centre for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, 100871 Beijing, China.,Center for Precision Medicine Multi-Omics Research, Peking University Health Science Center, 100191 Beijing, China.,School of Basic Medical Sciences, Peking University Health Science Center, 100191 Beijing, China.,Peking University First Hospital, 100034 Beijing, China.,Advanced Innovation Center for Human Brain Protection, Capital Medical University, 100069 Beijing, China
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24
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Extensive Changes in Transcription Dynamics Reflected on Alternative Splicing Events in Systemic Lupus Erythematosus Patients. Genes (Basel) 2021; 12:genes12081260. [PMID: 34440434 PMCID: PMC8392844 DOI: 10.3390/genes12081260] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/16/2021] [Accepted: 08/17/2021] [Indexed: 11/17/2022] Open
Abstract
In addition to increasing the complexity of the transcriptional output, alternative RNA splicing can lead to the reduction of mRNA translation or the production of non-functional or malfunctional proteins, thus representing a vital component of the gene regulation process. Herein, we set out to detect and characterize alternative splicing events that occur in whole-blood samples of patients with Systemic Lupus Erythematosus (SLE) as compared to healthy counterparts. Through the implementation of a computational pipeline on published RNA-sequencing data, we identified extensive changes in the transcription dynamics affecting a large number of genes. We found a predominance of intron retention events, with the majority introducing premature stop codons, suggestive of gene repression, in both inactive and active SLE patient samples. Alternative splicing affected a distinct set of genes from the ones detected as differentially expressed in the same comparisons, while alternatively spliced genes tended to reside in genome areas associated with increased gene co-expression. Functional analysis of genes affected by alternative splicing pointed towards particular functions related to metabolism and histone acetylation as of potential interest. Together, our findings underline the importance of incorporating alternative splicing analyses in the context of molecular characterization of complex diseases such as SLE.
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25
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Herbrechter R, Hube N, Buchholz R, Reiner A. Splicing and editing of ionotropic glutamate receptors: a comprehensive analysis based on human RNA-Seq data. Cell Mol Life Sci 2021; 78:5605-5630. [PMID: 34100982 PMCID: PMC8257547 DOI: 10.1007/s00018-021-03865-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 05/12/2021] [Accepted: 05/22/2021] [Indexed: 12/11/2022]
Abstract
Ionotropic glutamate receptors (iGluRs) play key roles for signaling in the central nervous system. Alternative splicing and RNA editing are well-known mechanisms to increase iGluR diversity and to provide context-dependent regulation. Earlier work on isoform identification has focused on the analysis of cloned transcripts, mostly from rodents. We here set out to obtain a systematic overview of iGluR splicing and editing in human brain based on RNA-Seq data. Using data from two large-scale transcriptome studies, we established a workflow for the de novo identification and quantification of alternative splice and editing events. We detected all canonical iGluR splice junctions, assessed the abundance of alternative events described in the literature, and identified new splice events in AMPA, kainate, delta, and NMDA receptor subunits. Notable events include an abundant transcript encoding the GluA4 amino-terminal domain, GluA4-ATD, a novel C-terminal GluD1 (delta receptor 1) isoform, GluD1-b, and potentially new GluK4 and GluN2C isoforms. C-terminal GluN1 splicing may be controlled by inclusion of a cassette exon, which shows preference for one of the two acceptor sites in the last exon. Moreover, we identified alternative untranslated regions (UTRs) and species-specific differences in splicing. In contrast, editing in exonic iGluR regions appears to be mostly limited to ten previously described sites, two of which result in silent amino acid changes. Coupling of proximal editing/editing and editing/splice events occurs to variable degree. Overall, this analysis provides the first inventory of alternative splicing and editing in human brain iGluRs and provides the impetus for further transcriptome-based and functional investigations.
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Affiliation(s)
- Robin Herbrechter
- Department of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Nadine Hube
- Department of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Raoul Buchholz
- Department of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Andreas Reiner
- Department of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany.
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