1
|
Geisler MS, Kemp JP, Duronio RJ. Histone locus bodies: a paradigm for how nuclear biomolecular condensates control cell cycle regulated gene expression. Nucleus 2023; 14:2293604. [PMID: 38095604 PMCID: PMC10730174 DOI: 10.1080/19491034.2023.2293604] [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: 09/29/2023] [Accepted: 12/07/2023] [Indexed: 12/18/2023] Open
Abstract
Histone locus bodies (HLBs) are biomolecular condensates that assemble at replication-dependent (RD) histone genes in animal cells. These genes produce unique mRNAs that are not polyadenylated and instead end in a conserved 3' stem loop critical for coordinated production of histone proteins during S phase of the cell cycle. Several evolutionarily conserved factors necessary for synthesis of RD histone mRNAs concentrate only in the HLB. Moreover, because HLBs are present throughout the cell cycle even though RD histone genes are only expressed during S phase, changes in HLB composition during cell cycle progression drive much of the cell cycle regulation of RD histone gene expression. Thus, HLBs provide a powerful opportunity to determine the cause-and-effect relationships between nuclear body formation and cell cycle regulated gene expression. In this review, we focus on progress during the last five years that has advanced our understanding of HLB biology.
Collapse
Affiliation(s)
- Mark S. Geisler
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC, USA
| | - James P. Kemp
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
| | - Robert J. Duronio
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC, USA
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA
| |
Collapse
|
2
|
Yang XC, Desotell A, Lin MH, Paige AS, Malinowska A, Sun Y, Aik WS, Dadlez M, Tong L, Dominski Z. In vitro methylation of the U7 snRNP subunits Lsm11 and SmE by the PRMT5/MEP50/pICln methylosome. RNA (NEW YORK, N.Y.) 2023; 29:1673-1690. [PMID: 37562960 PMCID: PMC10578488 DOI: 10.1261/rna.079709.123] [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: 05/10/2023] [Accepted: 07/08/2023] [Indexed: 08/12/2023]
Abstract
U7 snRNP is a multisubunit endonuclease required for 3' end processing of metazoan replication-dependent histone pre-mRNAs. In contrast to the spliceosomal snRNPs, U7 snRNP lacks the Sm subunits D1 and D2 and instead contains two related proteins, Lsm10 and Lsm11. The remaining five subunits of the U7 heptameric Sm ring, SmE, F, G, B, and D3, are shared with the spliceosomal snRNPs. The pathway that assembles the unique ring of U7 snRNP is unknown. Here, we show that a heterodimer of Lsm10 and Lsm11 tightly interacts with the methylosome, a complex of the arginine methyltransferase PRMT5, MEP50, and pICln known to methylate arginines in the carboxy-terminal regions of the Sm proteins B, D1, and D3 during the spliceosomal Sm ring assembly. Both biochemical and cryo-EM structural studies demonstrate that the interaction is mediated by PRMT5, which binds and methylates two arginine residues in the amino-terminal region of Lsm11. Surprisingly, PRMT5 also methylates an amino-terminal arginine in SmE, a subunit that does not undergo this type of modification during the biogenesis of the spliceosomal snRNPs. An intriguing possibility is that the unique methylation pattern of Lsm11 and SmE plays a vital role in the assembly of the U7 snRNP.
Collapse
Affiliation(s)
- Xiao-Cui Yang
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Anthony Desotell
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Min-Han Lin
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Andrew S Paige
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Agata Malinowska
- Department of Biophysics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Yadong Sun
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Wei Shen Aik
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Michał Dadlez
- Department of Biophysics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Warsaw University, 02-106 Warsaw, Poland
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Zbigniew Dominski
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| |
Collapse
|
3
|
Yang XC, Desotell A, Lin MH, Paige AS, Malinowska A, Sun Y, Aik WS, Dadlez M, Tong L, Dominski Z. In vitro methylation of the U7 snRNP subunits Lsm11 and SmE by the PRMT5/MEP50/pICln methylosome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.10.540203. [PMID: 37215023 PMCID: PMC10197641 DOI: 10.1101/2023.05.10.540203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
U7 snRNP is a multi-subunit endonuclease required for 3' end processing of metazoan replication-dependent histone pre-mRNAs. In contrast to the spliceosomal snRNPs, U7 snRNP lacks the Sm subunits D1 and D2 and instead contains two related proteins, Lsm10 and Lsm11. The remaining five subunits of the U7 heptameric Sm ring, SmE, F, G, B and D3, are shared with the spliceosomal snRNPs. The pathway that assembles the unique ring of U7 snRNP is unknown. Here, we show that a heterodimer of Lsm10 and Lsm11 tightly interacts with the methylosome, a complex of the arginine methyltransferase PRMT5, MEP50 and pICln known to methylate arginines in the C-terminal regions of the Sm proteins B, D1 and D3 during the spliceosomal Sm ring assembly. Both biochemical and Cryo-EM structural studies demonstrate that the interaction is mediated by PRMT5, which binds and methylates two arginine residues in the N-terminal region of Lsm11. Surprisingly, PRMT5 also methylates an N-terminal arginine in SmE, a subunit that does not undergo this type of modification during the biogenesis of the spliceosomal snRNPs. An intriguing possibility is that the unique methylation pattern of Lsm11 and SmE plays a vital role in the assembly of the U7 snRNP.
Collapse
|
4
|
Ielasi FS, Ternifi S, Fontaine E, Iuso D, Couté Y, Palencia A. Human histone pre-mRNA assembles histone or canonical mRNA-processing complexes by overlapping 3'-end sequence elements. Nucleic Acids Res 2022; 50:12425-12443. [PMID: 36447390 PMCID: PMC9756948 DOI: 10.1093/nar/gkac878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 09/20/2022] [Accepted: 10/10/2022] [Indexed: 12/05/2022] Open
Abstract
Human pre-mRNA processing relies on multi-subunit macromolecular complexes, which recognize specific RNA sequence elements essential for assembly and activity. Canonical pre-mRNA processing proceeds via the recognition of a polyadenylation signal (PAS) and a downstream sequence element (DSE), and produces polyadenylated mature mRNAs, while replication-dependent (RD) histone pre-mRNA processing requires association with a stem-loop (SL) motif and a histone downstream element (HDE), and produces cleaved but non-polyadenylated mature mRNAs. H2AC18 mRNA, a specific H2A RD histone pre-mRNA, can be processed to give either a non-polyadenylated mRNA, ending at the histone SL, or a polyadenylated mRNA. Here, we reveal how H2AC18 captures the two human pre-mRNA processing complexes in a mutually exclusive mode by overlapping a canonical PAS (AAUAAA) sequence element with a HDE. Disruption of the PAS sequence on H2AC18 pre-mRNA prevents recruitment of the canonical complex in vitro, without affecting the histone machinery. This shows how the relative position of cis-acting elements in histone pre-mRNAs allows the selective recruitment of distinct human pre-mRNA complexes, thereby expanding the capability to regulate 3' processing and polyadenylation.
Collapse
Affiliation(s)
- Francesco S Ielasi
- Institute for Advanced Biosciences (IAB), Structural Biology of Novel Targets in Human Diseases, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Sara Ternifi
- Institute for Advanced Biosciences (IAB), Structural Biology of Novel Targets in Human Diseases, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Emeline Fontaine
- Institute for Advanced Biosciences (IAB), Structural Biology of Novel Targets in Human Diseases, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Domenico Iuso
- Institute for Advanced Biosciences (IAB), Epigenetics and Cell Signaling, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Yohann Couté
- Université Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Andrés Palencia
- To whom correspondence should be addressed. Tel: +33 476 54 95 75;
| |
Collapse
|
5
|
Gutierrez PA, Baughman K, Sun Y, Tong L. A real-time fluorescence assay for CPSF73, the nuclease for pre-mRNA 3'-end processing. RNA (NEW YORK, N.Y.) 2021; 27:1148-1154. [PMID: 34230059 PMCID: PMC8457007 DOI: 10.1261/rna.078764.121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 06/17/2021] [Indexed: 05/09/2023]
Abstract
CPSF73 is the endonuclease that catalyzes the cleavage reaction for 3'-end processing of mRNA precursors (pre-mRNAs) in two distinct machineries, a canonical machinery for the majority of pre-mRNAs and a U7 snRNP (U7 machinery) for replication-dependent histone pre-mRNAs in animal cells. CPSF73 also possesses 5'-3' exonuclease activity in the U7 machinery, degrading the downstream cleavage product after the endonucleolytic cleavage. Recent studies show that CPSF73 is a potential target for developing anticancer, antimalarial, and antiprotozoal drugs, spurring interest in identifying new small-molecule inhibitors against this enzyme. CPSF73 nuclease activity has so far been demonstrated using a gel-based end-point assay, using radiolabeled or fluorescently labeled RNA substrates. By taking advantage of unique properties of the U7 machinery, we have developed a novel, real-time fluorescence assay for the nuclease activity of CPSF73. This assay is facile and high-throughput, and should also be helpful for the discovery of new CPSF73 inhibitors.
Collapse
Affiliation(s)
- Pedro A Gutierrez
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Kirk Baughman
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Yadong Sun
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| |
Collapse
|
6
|
U7 deciphered: the mechanism that forms the unusual 3' end of metazoan replication-dependent histone mRNAs. Biochem Soc Trans 2021; 49:2229-2240. [PMID: 34351387 DOI: 10.1042/bst20210323] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 11/17/2022]
Abstract
In animal cells, replication-dependent histone mRNAs end with a highly conserved stem-loop structure followed by a 4- to 5-nucleotide single-stranded tail. This unique 3' end distinguishes replication-dependent histone mRNAs from all other eukaryotic mRNAs, which end with a poly(A) tail produced by the canonical 3'-end processing mechanism of cleavage and polyadenylation. The pioneering studies of Max Birnstiel's group demonstrated nearly 40 years ago that the unique 3' end of animal replication-dependent histone mRNAs is generated by a distinct processing mechanism, whereby histone mRNA precursors are cleaved downstream of the stem-loop, but this cleavage is not followed by polyadenylation. The key role is played by the U7 snRNP, a complex of a ∼60 nucleotide U7 snRNA and many proteins. Some of these proteins, including the enzymatic component CPSF73, are shared with the canonical cleavage and polyadenylation machinery, justifying the view that the two metazoan pre-mRNA 3'-end processing mechanisms have a common evolutionary origin. The studies on U7 snRNP culminated in the recent breakthrough of reconstituting an entirely recombinant human machinery that is capable of accurately cleaving histone pre-mRNAs, and determining its structure in complex with a pre-mRNA substrate (with 13 proteins and two RNAs) that is poised for the cleavage reaction. The structure uncovered an unanticipated network of interactions within the U7 snRNP and a remarkable mechanism of activating catalytically dormant CPSF73 for the cleavage. This work provides a conceptual framework for understanding other eukaryotic 3'-end processing machineries.
Collapse
|
7
|
From Antisense RNA to RNA Modification: Therapeutic Potential of RNA-Based Technologies. Biomedicines 2021; 9:biomedicines9050550. [PMID: 34068948 PMCID: PMC8156014 DOI: 10.3390/biomedicines9050550] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 05/07/2021] [Accepted: 05/10/2021] [Indexed: 02/07/2023] Open
Abstract
Therapeutic oligonucleotides interact with a target RNA via Watson-Crick complementarity, affecting RNA-processing reactions such as mRNA degradation, pre-mRNA splicing, or mRNA translation. Since they were proposed decades ago, several have been approved for clinical use to correct genetic mutations. Three types of mechanisms of action (MoA) have emerged: RNase H-dependent degradation of mRNA directed by short chimeric antisense oligonucleotides (gapmers), correction of splicing defects via splice-modulation oligonucleotides, and interference of gene expression via short interfering RNAs (siRNAs). These antisense-based mechanisms can tackle several genetic disorders in a gene-specific manner, primarily by gene downregulation (gapmers and siRNAs) or splicing defects correction (exon-skipping oligos). Still, the challenge remains for the repair at the single-nucleotide level. The emerging field of epitranscriptomics and RNA modifications shows the enormous possibilities for recoding the transcriptome and repairing genetic mutations with high specificity while harnessing endogenously expressed RNA processing machinery. Some of these techniques have been proposed as alternatives to CRISPR-based technologies, where the exogenous gene-editing machinery needs to be delivered and expressed in the human cells to generate permanent (DNA) changes with unknown consequences. Here, we review the current FDA-approved antisense MoA (emphasizing some enabling technologies that contributed to their success) and three novel modalities based on post-transcriptional RNA modifications with therapeutic potential, including ADAR (Adenosine deaminases acting on RNA)-mediated RNA editing, targeted pseudouridylation, and 2′-O-methylation.
Collapse
|
8
|
Sun Y, Aik WS, Yang XC, Marzluff WF, Dominski Z, Tong L. Reconstitution and biochemical assays of an active human histone pre-mRNA 3'-end processing machinery. Methods Enzymol 2021; 655:291-324. [PMID: 34183127 DOI: 10.1016/bs.mie.2021.03.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In animal cells, replication-dependent histone pre-mRNAs are processed at the 3'-end by an endonucleolytic cleavage carried out by the U7 snRNP, a machinery that contains the U7 snRNA and many protein subunits. Studies on the composition of this machinery and understanding of its role in 3'-end processing were greatly facilitated by the development of an in vitro system utilizing nuclear extracts from mammalian cells 35 years ago and later from Drosophila cells. Most recently, recombinant expression and purification of the components of the machinery have enabled the full reconstitution of an active machinery and its complex with a model pre-mRNA substrate, using 13 proteins and 2 RNAs, and the determination of the structure of this active machinery. This chapter presents protocols for preparing nuclear extracts containing endogenous processing machinery, for assembling semi-recombinant and fully reconstituted machineries, and for histone pre-mRNA 3'-end processing assays with these samples.
Collapse
Affiliation(s)
- Yadong Sun
- Department of Biological Sciences, Columbia University, New York, NY, United States
| | - Wei Shen Aik
- Department of Biological Sciences, Columbia University, New York, NY, United States
| | - Xiao-Cui Yang
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - William F Marzluff
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States; Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Zbigniew Dominski
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States; Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, NY, United States.
| |
Collapse
|
9
|
Yang XC, Sun Y, Aik WS, Marzluff WF, Tong L, Dominski Z. Studies with recombinant U7 snRNP demonstrate that CPSF73 is both an endonuclease and a 5'-3' exonuclease. RNA (NEW YORK, N.Y.) 2020; 26:1345-1359. [PMID: 32554553 PMCID: PMC7491329 DOI: 10.1261/rna.076273.120] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 05/26/2020] [Indexed: 05/24/2023]
Abstract
Metazoan replication-dependent histone pre-mRNAs are cleaved at the 3' end by U7 snRNP, an RNA-guided endonuclease that contains U7 snRNA, seven proteins of the Sm ring, FLASH, and four polyadenylation factors: symplekin, CPSF73, CPSF100, and CstF64. A fully recombinant U7 snRNP was recently reconstituted from all 13 components for functional and structural studies and shown to accurately cleave histone pre-mRNAs. Here, we analyzed the activity of recombinant U7 snRNP in more detail. We demonstrate that in addition to cleaving histone pre-mRNAs endonucleolytically, reconstituted U7 snRNP acts as a 5'-3' exonuclease that degrades the downstream product generated from histone pre-mRNAs as a result of the endonucleolytic cleavage. Surprisingly, recombinant U7 snRNP also acts as an endonuclease on single-stranded DNA substrates. All these activities depend on the ability of U7 snRNA to base-pair with the substrate and on the presence of the amino-terminal domain (NTD) of symplekin in either cis or trans, and are abolished by mutations within the catalytic center of CPSF73, or by binding of the NTD to the SSU72 phosphatase of RNA polymerase II. Altogether, our results demonstrate that recombinant U7 snRNP functionally mimics its endogenous counterpart and provide evidence that CPSF73 is both an endonuclease and a 5'-3' exonuclease, consistent with the activity of other members of the β-CASP family. Our results also raise the intriguing possibility that CPSF73 may be involved in some aspects of DNA metabolism in vivo.
Collapse
Affiliation(s)
- Xiao-Cui Yang
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Yadong Sun
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Wei Shen Aik
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - William F Marzluff
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Zbigniew Dominski
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| |
Collapse
|
10
|
Eaton JD, West S. Termination of Transcription by RNA Polymerase II: BOOM! Trends Genet 2020; 36:664-675. [DOI: 10.1016/j.tig.2020.05.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 12/22/2022]
|
11
|
Sun Y, Zhang Y, Aik WS, Yang XC, Marzluff WF, Walz T, Dominski Z, Tong L. Structure of an active human histone pre-mRNA 3'-end processing machinery. Science 2020; 367:700-703. [PMID: 32029631 DOI: 10.1126/science.aaz7758] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/31/2019] [Indexed: 01/10/2023]
Abstract
The 3'-end processing machinery for metazoan replication-dependent histone precursor messenger RNAs (pre-mRNAs) contains the U7 small nuclear ribonucleoprotein and shares the key cleavage module with the canonical cleavage and polyadenylation machinery. We reconstituted an active human histone pre-mRNA processing machinery using 13 recombinant proteins and two RNAs and determined its structure by cryo-electron microscopy. The overall structure is highly asymmetrical and resembles an amphora with one long handle. We captured the pre-mRNA in the active site of the endonuclease, the 73-kilodalton subunit of the cleavage and polyadenylation specificity factor, poised for cleavage. The endonuclease and the entire cleavage module undergo extensive rearrangements for activation, triggered through the recognition of the duplex between the authentic pre-mRNA and U7 small nuclear RNA (snRNA). Our study also has notable implications for understanding canonical and snRNA 3'-end processing.
Collapse
Affiliation(s)
- Yadong Sun
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Yixiao Zhang
- Laboratory of Molecular Electron Microscopy, Rockefeller University, New York, NY 10065, USA
| | - Wei Shen Aik
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Xiao-Cui Yang
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - William F Marzluff
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Thomas Walz
- Laboratory of Molecular Electron Microscopy, Rockefeller University, New York, NY 10065, USA.
| | - Zbigniew Dominski
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. .,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
| |
Collapse
|