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Aw JGA, Lim SW, Wang JX, Lambert FRP, Tan WT, Shen Y, Zhang Y, Kaewsapsak P, Li C, Ng SB, Vardy LA, Tan MH, Nagarajan N, Wan Y. Determination of isoform-specific RNA structure with nanopore long reads. Nat Biotechnol 2020; 39:336-346. [PMID: 33106685 DOI: 10.1038/s41587-020-0712-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 09/18/2020] [Indexed: 01/10/2023]
Abstract
Current methods for determining RNA structure with short-read sequencing cannot capture most differences between distinct transcript isoforms. Here we present RNA structure analysis using nanopore sequencing (PORE-cupine), which combines structure probing using chemical modifications with direct long-read RNA sequencing and machine learning to detect secondary structures in cellular RNAs. PORE-cupine also captures global structural features, such as RNA-binding-protein binding sites and reactivity differences at single-nucleotide variants. We show that shared sequences in different transcript isoforms of the same gene can fold into different structures, highlighting the importance of long-read sequencing for obtaining phase information. We also demonstrate that structural differences between transcript isoforms of the same gene lead to differences in translation efficiency. By revealing isoform-specific RNA structure, PORE-cupine will deepen understanding of the role of structures in controlling gene regulation.
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Affiliation(s)
- Jong Ghut Ashley Aw
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, A*STAR, Singapore, Singapore
| | - Shaun W Lim
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, A*STAR, Singapore, Singapore
| | - Jia Xu Wang
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, A*STAR, Singapore, Singapore
| | - Finnlay R P Lambert
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, A*STAR, Singapore, Singapore.,Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Wen Ting Tan
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, A*STAR, Singapore, Singapore
| | - Yang Shen
- Computational and Systems Biology, Genome Institute of Singapore, A*STAR, Singapore, Singapore
| | - Yu Zhang
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, A*STAR, Singapore, Singapore
| | - Pornchai Kaewsapsak
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, A*STAR, Singapore, Singapore
| | - Chenhao Li
- Computational and Systems Biology, Genome Institute of Singapore, A*STAR, Singapore, Singapore
| | - Sarah B Ng
- Genome Technologies Platform, Genome Institute of Singapore, A*STAR, Singapore, Singapore
| | - Leah A Vardy
- Skin Research Institute of Singapore, A*STAR, Immunos, Singapore
| | - Meng How Tan
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, A*STAR, Singapore, Singapore.,School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
| | - Niranjan Nagarajan
- Computational and Systems Biology, Genome Institute of Singapore, A*STAR, Singapore, Singapore. .,Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
| | - Yue Wan
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, A*STAR, Singapore, Singapore. .,Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore. .,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
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2
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Minetti G, Ciana A, Balduini C. Differential sorting of tyrosine kinases and phosphotyrosine phosphatases acting on band 3 during vesiculation of human erythrocytes. Biochem J 2004; 377:489-97. [PMID: 14527338 PMCID: PMC1223870 DOI: 10.1042/bj20031401] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2003] [Accepted: 10/06/2003] [Indexed: 01/02/2023]
Abstract
One of the most intensively studied post-translational modifications of erythrocyte proteins is the phosphorylation of tyrosine residues of band 3, which is strictly regulated in vivo by PTKs (protein-tyrosine kinases) and PTPs (protein-phosphotyrosine phosphatases). Two PTKs (p72(syk) and p56/53(lyn)) and two PTP activities (PTP1B and SHPTP-2) have been immunologically identified so far in mature human erythrocytes. We have shown previously that band 3 undergoes tyrosine phosphorylation upon a decrease in cell volume, as occurs when erythrocytes treated with Ca(2+)/Ca(2+) ionophore (A23187) lose KCl and release microvesicles. Similar levels of band 3 tyrosine phosphorylation in vesicles and in the parent cells are induced by this treatment. However, we have found that tyrosine phosphorylation of band 3 in vesicles is more stable than in whole erythrocytes. Examination of how the identified PTPs and PTKs are partitioned between the vesicles and the remnant cells during vesiculation reveals that PTP1B, unlike the PTKs, is retained entirely in the parent cell compartment. Since a tight association between PTP1B and band 3 has been documented previously, we have investigated the partitioning of PTP1B and band 3 between the membrane and the membrane-skeletal fractions prepared from resting or Ca(2+)/A23187-treated cells. Our results rule out the possibility that the preferential retention of PTP1B within the cell was due to an increase in the amount of membrane-skeleton-associated band 3 (and of PTP1B) during the release of spectrin-free vesicles, suggesting a more complex modality of interaction of PTP1B with band 3 in the erythrocyte membrane. Analysis of erythrocytes of different cell ages revealed that PTP1B, unlike the other enzymes examined, was quantitatively conserved during erythrocyte aging. This suggests important roles for the down-regulation of tyrosine phosphorylation of band 3 in erythrocyte physiology, and for vesiculation as a mechanism of human erythrocyte senescence.
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Affiliation(s)
- Giampaolo Minetti
- Università di Pavia, Dipartimento di Biochimica A. Castellani, Sezione di Scienze, via Bassi 21, I-27100 Pavia, Italy.
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3
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Jordán JA, Alvarez FJ, Lotero LA, Tejedor MC, Díez JC. In vivo behaviour of rat band 3 cross-linked carrier erythrocytes. Biochimie 1998; 80:325-32. [PMID: 9672753 DOI: 10.1016/s0300-9084(98)80075-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Rat band 3 cross-linked carrier erythrocytes have been prepared. Iodinated carbonic anhydrase has been encapsulated into rat erythrocytes. Then, carrier erythrocytes were labeled with 51chromium. Eventually, these doubly labeled rat RBCs were treated with a band 3 cross-linking reagent, namely bis(sulfosuccinimidyl)suberate (BS3). 51Chromium labeling and 125I CA showed to have cytosolic localization in cross-linked carrier erythrocytes. Estimation of the band 3 cross-linking induced by BS3 on rat carrier erythrocytes has been done rendering values around 25% of band 3 monomer reduction. BS3-cross-linked carrier erythrocytes when injected into rats are mainly targeted to liver as shown by chromium labeling localization. Also, encapsulated CA radioactivity carried by cross-linked carrier rat erythrocytes when injected into rats is localized predominantly in liver as shown by in vivo experiments. Accordingly, cross-linked carrier erythrocytes are highly recognized by peritoneal macrophages as detected by in vitro analyses of macrophage recognition. Thus, our data revealed a targeting of carrier rat erythrocytes induced by cross-linking of band 3 protein by BS3. These results support claims in favor of this animal model as a feasible system to analyze cross-linked carrier erythrocytes survival and targeting as well as the in vivo efficacy of targeting of loaded compounds to liver.
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Affiliation(s)
- J A Jordán
- Departamento de Bioquímica y Biología Molecular, Universidad de Alcalá
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4
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Piccinini G, Minetti G, Balduini C, Brovelli A. Oxidation state of glutathione and membrane proteins in human red cells of different age. Mech Ageing Dev 1995; 78:15-26. [PMID: 7603087 DOI: 10.1016/0047-6374(94)01511-j] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In this study the oxidation state of glutathione and membrane proteins was analyzed in red cells of different age in basal conditions. Red cells of different age were prepared by centrifugation and separated according to their density by two procedures: on self-forming gradients of autologous plasma (Murphy's procedure) and on discontinuous Stractan gradients. The efficiency of the two procedures in the isolation of senescent cells was compared. The results indicate that, despite the evidence that total cell GSH decreases with aging, its concentration, evaluated in the cell preparations of different ages, remains constant throughout the red cell life, when correlated with cell water content. Glutathione disulfide concentration increases with aging. The oxidation state of membrane proteins does not seem to change during the red cell life span.
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Affiliation(s)
- G Piccinini
- Dipartimento di Biochimica, Università degli Studi, Pavia, Italy
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5
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Seppi C, Castellana MA, Minetti G, Piccinini G, Balduini C, Brovelli A. Evidence for membrane protein oxidation during in vivo aging of human erythrocytes. Mech Ageing Dev 1991; 57:247-58. [PMID: 2056779 DOI: 10.1016/0047-6374(91)90050-a] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Oxidative lesions to membrane proteins were studied in human erythrocytes of different age and were evaluated on ghost membrane preparations by assaying thiol and methionine sulphoxide groups, and in situ on intact cells, after treating erythrocytes with the fluorochrome N-(7-dimethyl-amino-4-methyl-coumarinyl) maleimide (DACM). DACM reacts with thiol groups and the amount of this reagent bound by membrane proteins was quantified after SDS-PAGE separation. Results obtained show that during aging of normal cells the oxidative state of membrane proteins increases: this was better shown by the assay of methionine sulphoxide residues rather than by the thiol titration, when studies were carried out on ghost membranes. After separation of individual membrane proteins by SDS-PAGE, decreased accessibility of DACM to thiol groups of band 3 and of the main proteins of the membrane skeleton was evident in senescent erythrocytes. These results show that during aging, band 3 and membrane skeleton proteins undergo conformational changes and/or oxidation. Similar results were obtained when thiol distribution was studied in membrane proteins separated by SDS-PAGE in both reducing and non-reducing conditions.
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Affiliation(s)
- C Seppi
- Dipartimento di Biochimica, Università degli Studi, Pavia, Italy
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Misra DN, Gill TJ, Kunz HW. Characterization of the RT2 antigens of the rat erythrocyte membrane. JOURNAL OF IMMUNOGENETICS 1981; 8:51-66. [PMID: 6166690 DOI: 10.1111/j.1744-313x.1981.tb01072.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Haemagglutination inhibition studies using isolated membrane components from rat red blood cells showed that the activity of the major antigenic system RT2 was contained exclusively in the glycoprotein fraction and confirmed immunochemically the existence of two alleles, RT2 a and RT2 b. The SDS-PAGE analysis of the membrane showed two interconvertible glycoproteins of apparent molecular weight 72,000 and 36,000, and the higher molecular weight component appeared to be a dimer of the lower molecular weight one. Analysis of the various membrane preparations after 125I-labelling showed that the glycoproteins existed in at least two molecular species on the surface of the red cells and that one species was more readily radio-iodinated and dimerized than the other. The RT2 antigenic specificities were preferentially associated with this component.
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10
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Howard RJ, Smith PM, Mitchell GF. Identification of differences between the surface proteins and glycoproteins of normal mouse (Balb/c) and human erythrocytes. J Membr Biol 1979; 49:171-98. [PMID: 226711 DOI: 10.1007/bf01868724] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The topography of the external surface of the Balb/c mouse erythrocyte has been investigated and compared to the human erythrocyte by using a series of protein radiolabeling probes. After sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the pattern of Coomassie Blue stained proteins was very similar for mouse and human erythrocyte ghosts, as was the distribution of radioactivity in protein bands after lactoperoxidase catalyzed radioiodination. The mouse erythrocyte glycoproteins identified by periodic-acid-Schiff and 'Stains-All' reagents, sialic acid analysis of gel slices, binding of 125I-wheat germ agglutinin and 125I-concanavalin A to the gels, and glycoprotein radiolabeling techniques, differed markedly from the sets of proteins labeled by radioiodination, and also differed from the human erythrocyte glycoproteins. Instead of the PAS I to PAS IV series of sialoglycoproteins characteristic of human erythrocytes, the mouse erythrocyte possesses a broad band of sialoglycoproteins with several peaks ranging in mol wt from 65,000 to 32,000. The same group of sialoglycoproteins were labeled by the periodate/B3H4-technique specific for terminal sialic acid, and the galactose oxidase/B3H4-method (plus neuraminidase) specific for galactosyl/N-acetylgalactosaminyl residues penultimate to sialic acid. These results emphasize the necessity to employ a variety of protein radiolabeling probes based on different labeling specificities, to study the membrane topography of cells which are poorly understood compared to the human erythrocyte membrane.
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Fehlmann M, Lafleur L, Marceau N. Surface membrane differentiation of hemopoietic cells as observed by radioactive labeling. J Cell Physiol 1977; 90:455-64. [PMID: 853063 DOI: 10.1002/jcp.1040900309] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Bone marrow cells from normal rats were separated by velocity sedimentation into three distinct populations corresponding to granulocytes, lymphocytes and reticulocytes. Cells from each population were surface labelled via the lactoperoxidase radioiodination or the tritiated borohydride reduction. Distinct labeling patterns were observed on SDS-PAGE for each cell populations. Separation of bone marrow cells from anemic rats injected with TAB vaccine led to four populations corresponding to successive stages of erythroid cell maturation. Labelled protein patterns were not in this case as different from one population to the other, except for one species which increased in intensity with the degree of maturation. The tritiated glycoprotein profiles show a shift from high to low molecular weight species during the process of maturation.
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12
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Chang H, Langer PJ, Lodish HF. Asynchronous synthesis of erythrocyte membrane proteins. Proc Natl Acad Sci U S A 1976; 73:3206-10. [PMID: 1067613 PMCID: PMC430981 DOI: 10.1073/pnas.73.9.3206] [Citation(s) in RCA: 75] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The synthesis of membrane proteins of the mature mouse erythrocyte is asynchronous. During erythropoiesis, synthesis of the bulk of the spectrin and actin polypeptides is completed before that of the major transmembrane glycoprotein. Synthesis of the glycoprotein ceases before that of several minor proteins found on the inner surface of the red cell membrane, and one of these minor proteins is made predominantly by reticulocytes. These findings were the result of experiments in which a normal mouse was given a single injection of [35S]methionine. The appearance of radioactivity in the membrane proteins of circulating mature erythrocytes was followed. The earliest labeled proteins to emerge into the blood represent those synthesized at the last stages of erythropoiesis.
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