1
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Wright SE, Todd PK. Native functions of short tandem repeats. eLife 2023; 12:e84043. [PMID: 36940239 PMCID: PMC10027321 DOI: 10.7554/elife.84043] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 03/08/2023] [Indexed: 03/21/2023] Open
Abstract
Over a third of the human genome is comprised of repetitive sequences, including more than a million short tandem repeats (STRs). While studies of the pathologic consequences of repeat expansions that cause syndromic human diseases are extensive, the potential native functions of STRs are often ignored. Here, we summarize a growing body of research into the normal biological functions for repetitive elements across the genome, with a particular focus on the roles of STRs in regulating gene expression. We propose reconceptualizing the pathogenic consequences of repeat expansions as aberrancies in normal gene regulation. From this altered viewpoint, we predict that future work will reveal broader roles for STRs in neuronal function and as risk alleles for more common human neurological diseases.
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Affiliation(s)
- Shannon E Wright
- Department of Neurology, University of Michigan–Ann ArborAnn ArborUnited States
- Neuroscience Graduate Program, University of Michigan–Ann ArborAnn ArborUnited States
- Department of Neuroscience, Picower InstituteCambridgeUnited States
| | - Peter K Todd
- Department of Neurology, University of Michigan–Ann ArborAnn ArborUnited States
- VA Ann Arbor Healthcare SystemAnn ArborUnited States
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2
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Pande A, Patiyal S, Lathwal A, Arora C, Kaur D, Dhall A, Mishra G, Kaur H, Sharma N, Jain S, Usmani SS, Agrawal P, Kumar R, Kumar V, Raghava GPS. Pfeature: A Tool for Computing Wide Range of Protein Features and Building Prediction Models. J Comput Biol 2023; 30:204-222. [PMID: 36251780 DOI: 10.1089/cmb.2022.0241] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
In the last three decades, a wide range of protein features have been discovered to annotate a protein. Numerous attempts have been made to integrate these features in a software package/platform so that the user may compute a wide range of features from a single source. To complement the existing methods, we developed a method, Pfeature, for computing a wide range of protein features. Pfeature allows to compute more than 200,000 features required for predicting the overall function of a protein, residue-level annotation of a protein, and function of chemically modified peptides. It has six major modules, namely, composition, binary profiles, evolutionary information, structural features, patterns, and model building. Composition module facilitates to compute most of the existing compositional features, plus novel features. The binary profile of amino acid sequences allows to compute the fraction of each type of residue as well as its position. The evolutionary information module allows to compute evolutionary information of a protein in the form of a position-specific scoring matrix profile generated using Position-Specific Iterative Basic Local Alignment Search Tool (PSI-BLAST); fit for annotation of a protein and its residues. A structural module was developed for computing of structural features/descriptors from a tertiary structure of a protein. These features are suitable to predict the therapeutic potential of a protein containing non-natural or chemically modified residues. The model-building module allows to implement various machine learning techniques for developing classification and regression models as well as feature selection. Pfeature also allows the generation of overlapping patterns and features from a protein. A user-friendly Pfeature is available as a web server python library and stand-alone package.
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Affiliation(s)
- Akshara Pande
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India
| | - Sumeet Patiyal
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India
| | - Anjali Lathwal
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India
| | - Chakit Arora
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India
| | - Dilraj Kaur
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India
| | - Anjali Dhall
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India
| | - Gaurav Mishra
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India.,Department of Electrical Engineering, Shiv Nadar University, Greater Noida, India
| | - Harpreet Kaur
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India.,Bioinformatics Centre, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Neelam Sharma
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India
| | - Shipra Jain
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India
| | - Salman Sadullah Usmani
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India.,Bioinformatics Centre, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Piyush Agrawal
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India.,Bioinformatics Centre, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Rajesh Kumar
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India.,Bioinformatics Centre, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Vinod Kumar
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India.,Bioinformatics Centre, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Gajendra P S Raghava
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India
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3
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Pelassa I, Cibelli M, Villeri V, Lilliu E, Vaglietti S, Olocco F, Ghirardi M, Montarolo PG, Corà D, Fiumara F. Compound Dynamics and Combinatorial Patterns of Amino Acid Repeats Encode a System of Evolutionary and Developmental Markers. Genome Biol Evol 2020; 11:3159-3178. [PMID: 31589292 PMCID: PMC6839033 DOI: 10.1093/gbe/evz216] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2019] [Indexed: 01/05/2023] Open
Abstract
Homopolymeric amino acid repeats (AARs) like polyalanine (polyA) and polyglutamine (polyQ) in some developmental proteins (DPs) regulate certain aspects of organismal morphology and behavior, suggesting an evolutionary role for AARs as developmental "tuning knobs." It is still unclear, however, whether these are occasional protein-specific phenomena or hints at the existence of a whole AAR-based regulatory system in DPs. Using novel approaches to trace their functional and evolutionary history, we find quantitative evidence supporting a generalized, combinatorial role of AARs in developmental processes with evolutionary implications. We observe nonrandom AAR distributions and combinations in HOX and other DPs, as well as in their interactomes, defining elements of a proteome-wide combinatorial functional code whereby different AARs and their combinations appear preferentially in proteins involved in the development of specific organs/systems. Such functional associations can be either static or display detectable evolutionary dynamics. These findings suggest that progressive changes in AAR occurrence/combination, by altering embryonic development, may have contributed to taxonomic divergence, leaving detectable traces in the evolutionary history of proteomes. Consistent with this hypothesis, we find that the evolutionary trajectories of the 20 AARs in eukaryotic proteomes are highly interrelated and their individual or compound dynamics can sharply mark taxonomic boundaries, or display clock-like trends, carrying overall a strong phylogenetic signal. These findings provide quantitative evidence and an interpretive framework outlining a combinatorial system of AARs whose compound dynamics mark at the same time DP functions and evolutionary transitions.
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Affiliation(s)
- Ilaria Pelassa
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy
| | - Marica Cibelli
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy
| | - Veronica Villeri
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy
| | - Elena Lilliu
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy
| | - Serena Vaglietti
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy
| | - Federica Olocco
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy
| | - Mirella Ghirardi
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy.,National Institute of Neuroscience (INN), Torino, Italy
| | - Pier Giorgio Montarolo
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy.,National Institute of Neuroscience (INN), Torino, Italy
| | - Davide Corà
- Department of Translational Medicine, Piemonte Orientale University, Novara, Italy.,Center for Translational Research on Autoimmune and Allergic Disease (CAAD), Novara, Italy
| | - Ferdinando Fiumara
- Department of Neuroscience Rita Levi Montalcini, University of Torino, Italy.,National Institute of Neuroscience (INN), Torino, Italy
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4
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Kavouras M, Malandrakis EE, Danis T, Blom E, Anastassiadis K, Panagiotaki P, Exadactylos A. Hox Genes Polymorphism Depicts Developmental Disruption of Common Sole Eggs. Open Life Sci 2019; 14:549-563. [PMID: 33817191 PMCID: PMC7874752 DOI: 10.1515/biol-2019-0061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 11/22/2019] [Indexed: 12/31/2022] Open
Abstract
In sole aquaculture production, consistency in the quality of produced eggs throughout the year is unpredictable. Hox genes have a crucial role in controlling embryonic development and their genetic variation could alter the phenotype dramatically. In teleosts genome duplication led paralog hox genes to become diverged. Direct association of polymorphism in hoxa1a, hoxa2a & hoxa2b of Solea solea with egg viability indicates hoxa2b as a potential genetic marker. High Resolution Melt (HRM) analysis was carried out in 52 viable and 61 non-viable eggs collected at 54±6 hours post fertilization (hpf). Allelic and genotypic frequencies of polymorphism were analyzed and results illustrated a significantly increased risk for non-viability for minor alleles and their homozygous genotypes. Haplotype analysis demonstrated a significant recessive effect on the risk of non-viability, by increasing the odds of disrupting embryonic development up to three-fold. Phylogenetic analysis showed that the paralog genes hoxa2a and hoxa2b, are separated distinctly in two clades and presented a significant ω variation, revealing their diverged evolutionary rate.
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Affiliation(s)
| | - Emmanouil E. Malandrakis
- Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fytokou str, Volos, Greece
| | - Theodoros Danis
- Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fytokou str, Volos, Greece
| | - Ewout Blom
- Wageningen Marine Research, Wageningen University & Research, IJmuiden, The Netherlands
| | | | - Panagiota Panagiotaki
- Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fytokou str, Volos, Greece
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5
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Gao B, Wang J, Huang J, Huang X, Sha W, Qin L. The dynamic region of the peptidoglycan synthase gene, Rv0050, induces the growth rate and morphologic heterogeneity in Mycobacteria. INFECTION GENETICS AND EVOLUTION 2019; 72:86-92. [DOI: 10.1016/j.meegid.2018.12.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 11/30/2018] [Accepted: 12/07/2018] [Indexed: 12/16/2022]
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6
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Polyserine repeats promote coiled coil-mediated fibril formation and length-dependent protein aggregation. J Struct Biol 2018; 204:572-584. [PMID: 30194983 DOI: 10.1016/j.jsb.2018.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 08/06/2018] [Accepted: 09/01/2018] [Indexed: 12/13/2022]
Abstract
Short polyserine (polyS) repeats are frequently found in proteins and longer ones are produced in neurological disorders such as Huntington disease (HD) owing to translational frameshifting or non-ATG-dependent translation, together with polyglutamine (polyQ) and polyalanine (polyA) repeats, forming intracellular aggregates. However, the physiological and pathological structures of polyS repeats are not clearly understood. Early studies highlighted their structural versatility, similar to other homopolymers whose conformation is influenced by the surrounding protein context. As polyS stretches are frequently near polyQ and polyA repeats, which can be part of coiled coil (CC) structures, and the frameshift-derived polyS repeats in HD directly flank CC heptads important for aggregation, we investigate here the structural and aggregation properties of polyS in the context of CC structures. We have taken advantage of peptide models, previously used to study polyQ and polyA in CCs, in which we inserted polyS repeats of variable length and studied them in comparison with polyQ and polyA peptides. We found that polyS repeats promote CC-mediated polymerization and fibrillization as revealed by circular dichroism, chemical crosslinking, and atomic force microscopy. Furthermore, they promote CC-based, length-dependent intracellular aggregation, which is negligible with 7 and widespread with 49 serines. These findings show that polyS repeats can participate in the formation of CCs, as previously found for polyQ and polyA, conferring to peptides distinctive structural properties with aggregation kinetics that are intermediate between those of polyA and polyQ CCs, and contribute to an overall structural definition of the pathophysiogical roles of homopolymeric repeats in CC structures.
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7
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Abstract
Accumulating evidence suggests that many classes of DNA repeats exhibit attributes that distinguish them from other genetic variants, including the fact that they are more liable to mutation; this enables them to mediate genetic plasticity. The expansion of tandem repeats, particularly of short tandem repeats, can cause a range of disorders (including Huntington disease, various ataxias, motor neuron disease, frontotemporal dementia, fragile X syndrome and other neurological disorders), and emerging data suggest that tandem repeat polymorphisms (TRPs) can also regulate gene expression in healthy individuals. TRPs in human genomes may also contribute to the missing heritability of polygenic disorders. A better understanding of tandem repeats and their associated repeatome, as well as their capacity for genetic plasticity via both germline and somatic mutations, is needed to transform our understanding of the role of TRPs in health and disease.
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Affiliation(s)
- Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria, Australia
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8
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Barik S. Amino acid repeats avert mRNA folding through conservative substitutions and synonymous codons, regardless of codon bias. Heliyon 2017; 3:e00492. [PMID: 29387823 PMCID: PMC5772840 DOI: 10.1016/j.heliyon.2017.e00492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 12/06/2017] [Accepted: 12/13/2017] [Indexed: 11/18/2022] Open
Abstract
A significant number of proteins in all living species contains amino acid repeats (AARs) of various lengths and compositions, many of which play important roles in protein structure and function. Here, I have surveyed select homopolymeric single [(A)n] and double [(AB)n] AARs in the human proteome. A close examination of their codon pattern and analysis of RNA structure propensity led to the following set of empirical rules: (1) One class of amino acid repeats (Class I) uses a mixture of synonymous codons, some of which approximate the codon bias ratio in the overall human proteome; (2) The second class (Class II) disregards the codon bias ratio, and appears to have originated by simple repetition of the same codon (or just a few codons); and finally, (3) In all AARs (including Class I, Class II, and the in-betweens), the codons are chosen in a manner that precludes the formation of RNA secondary structure. It appears that the AAR genes have evolved by orchestrating a balance between codon usage and mRNA secondary structure. The insights gained here should provide a better understanding of AAR evolution and may assist in designing synthetic genes.
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9
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Lee JK, Ding Y, Conrad AL, Cattaneo E, Epping E, Mathews K, Gonzalez-Alegre P, Cahill L, Magnotta V, Schlaggar BL, Perlmutter JS, Kim REY, Dawson JD, Nopoulos P. Sex-specific effects of the Huntington gene on normal neurodevelopment. J Neurosci Res 2017; 95:398-408. [PMID: 27870408 DOI: 10.1002/jnr.23980] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 10/04/2016] [Accepted: 10/06/2016] [Indexed: 01/03/2023]
Abstract
Huntington disease is a neurodegenerative disorder caused by a gene (HTT) with a unique feature of trinucleotide repeats ranging from 10 to 35 in healthy people; when expanded beyond 39 repeats, Huntington disease develops. Animal models demonstrate that HTT is vital to brain development; however, this has not been studied in humans. Moreover, evidence suggests that triplet repeat genes may have been vital in evolution of the human brain. Here we evaluate brain structure using magnetic resonance imaging and brain function using cognitive tests in a sample of school-aged children ages 6 to 18 years old. DNA samples were processed to quantify the number of CAG repeats within HTT. We find that the number of repeats in HTT, below disease threshold, confers advantageous changes in brain structure and general intelligence (IQ): the higher the number of repeats, the greater the change in brain structure, and the higher the IQ. The pattern of structural brain changes associated with HTT is strikingly different between males and females. HTT may confer an advantage or a disadvantage depending on the repeat length, playing a key role in either the evolution of a superior human brain or development of a uniquely human brain disease. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Jessica K Lee
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Yue Ding
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Amy L Conrad
- Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Elena Cattaneo
- Department of Biosciences, University of Milan, Milan, Italy
| | - Eric Epping
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Kathy Mathews
- Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, Iowa.,Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Pedro Gonzalez-Alegre
- Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Larry Cahill
- Department of Neurobiology and Behavior, University of California, Irvine, California
| | - Vincent Magnotta
- Department of Radiology, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Bradley L Schlaggar
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri.,Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri.,Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri.,Department of Neurology, Washington University School of Medicine, St. Louis, Missouri.,Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri
| | - Joel S Perlmutter
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri.,Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri.,Department of Neurology, Washington University School of Medicine, St. Louis, Missouri
| | - Regina E Y Kim
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Jeffrey D Dawson
- Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, Iowa
| | - Peg Nopoulos
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, Iowa.,Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, Iowa.,Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, Iowa
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10
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Luo X, Tue PT, Sugiyama K, Takamura Y. High yield matrix-free ionization of biomolecules by pulse-heating ion source. Sci Rep 2017; 7:15170. [PMID: 29123135 PMCID: PMC5680173 DOI: 10.1038/s41598-017-15259-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 10/23/2017] [Indexed: 11/18/2022] Open
Abstract
Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry has been widely used for biomolecular analysis. However, with conventional MALDI, it is difficult to analyse low-molecular-weight compounds because of the interference of matrix ion signals. Here, we report a matrix-free on-chip pulse-heating desorption/ionization (PHDI) method for a wide range of biomolecules ranging from low molecular-weight substances such as glycine (75.7 Da) to large species such as α-lactalbumin (14.2 kDa). Compared with the conventional MALDI, the matrix-free PHDI method affords high yields of singly charged ions with very less fragmentation and background using only one-pulse without light (laser). We believe that this new technique for matrix-free biomolecules analysis would overcome the limitations of the conventional MALDI.
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Affiliation(s)
- Xi Luo
- School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa, 923-1211, Japan
| | - Phan-Trong Tue
- School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa, 923-1211, Japan
| | - Kiyotaka Sugiyama
- School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa, 923-1211, Japan
| | - Yuzuru Takamura
- School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa, 923-1211, Japan.
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11
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Abstract
In this review, we discuss how two evolutionarily conserved pathways at the interface of DNA replication and repair, template switching and break-induced replication, lead to the deleterious large-scale expansion of trinucleotide DNA repeats that cause numerous hereditary diseases. We highlight that these pathways, which originated in prokaryotes, may be subsequently hijacked to maintain long DNA microsatellites in eukaryotes. We suggest that the negative mutagenic outcomes of these pathways, exemplified by repeat expansion diseases, are likely outweighed by their positive role in maintaining functional repetitive regions of the genome such as telomeres and centromeres.
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Affiliation(s)
| | - Jane C Kim
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA, USA
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12
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Endow JK, Rocha AG, Baldwin AJ, Roston RL, Yamaguchi T, Kamikubo H, Inoue K. Polyglycine Acts as a Rejection Signal for Protein Transport at the Chloroplast Envelope. PLoS One 2016; 11:e0167802. [PMID: 27936133 PMCID: PMC5147994 DOI: 10.1371/journal.pone.0167802] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 11/21/2016] [Indexed: 11/19/2022] Open
Abstract
PolyGly is present in many proteins in various organisms. One example is found in a transmembrane β-barrel protein, translocon at the outer-envelope-membrane of chloroplasts 75 (Toc75). Toc75 requires its N-terminal extension (t75) for proper localization. t75 comprises signals for chloroplast import (n75) and envelope sorting (c75) in tandem. n75 and c75 are removed by stromal processing peptidase and plastidic type I signal peptidase 1, respectively. PolyGly is present within c75 and its deletion or substitution causes mistargeting of Toc75 to the stroma. Here we have examined the properties of polyGly-dependent protein targeting using two soluble passenger proteins, the mature portion of the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (mSS) and enhanced green fluorescent protein (EGFP). Both t75-mSS and t75-EGFP were imported into isolated chloroplasts and their n75 removed. Resultant c75-mSS was associated with the envelope at the intermembrane space, whereas c75-EGFP was partially exposed outside the envelope. Deletion of polyGly or substitution of tri-Ala for the critical tri-Gly segment within polyGly caused each passenger to be targeted to the stroma. Transient expression of t75-EGFP in Nicotiana benthamiana resulted in accumulation of c75-EGFP exposed at the surface of the chloroplast, but the majority of the EGFP passenger was found free in the cytosol with most of its c75 attachment removed. Results of circular dichroism analyses suggest that polyGly within c75 may form an extended conformation, which is disrupted by tri-Ala substitution. These data suggest that polyGly is distinct from a canonical stop-transfer sequence and acts as a rejection signal at the chloroplast inner envelope.
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Affiliation(s)
- Joshua K. Endow
- Department of Plant Sciences, University of California at Davis, One Shields Avenue, Davis, California, United States of America
| | - Agostinho Gomes Rocha
- Department of Plant Sciences, University of California at Davis, One Shields Avenue, Davis, California, United States of America
| | - Amy J. Baldwin
- Department of Plant Sciences, University of California at Davis, One Shields Avenue, Davis, California, United States of America
| | - Rebecca L. Roston
- Department of Plant Sciences, University of California at Davis, One Shields Avenue, Davis, California, United States of America
| | - Toshio Yamaguchi
- Department of Plant Sciences, University of California at Davis, One Shields Avenue, Davis, California, United States of America
| | - Hironari Kamikubo
- Graduate School of Materials Science, Nara Institute of Science and Technology, Takayama, Ikoma, Nara, Japan
| | - Kentaro Inoue
- Department of Plant Sciences, University of California at Davis, One Shields Avenue, Davis, California, United States of America
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13
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Estruch SB, Graham SA, Chinnappa SM, Deriziotis P, Fisher SE. Functional characterization of rare FOXP2 variants in neurodevelopmental disorder. J Neurodev Disord 2016; 8:44. [PMID: 27933109 PMCID: PMC5126810 DOI: 10.1186/s11689-016-9177-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 11/08/2016] [Indexed: 01/15/2023] Open
Abstract
Background Heterozygous disruption of FOXP2 causes a rare form of speech and language impairment. Screens of the FOXP2 sequence in individuals with speech/language-related disorders have identified several rare protein-altering variants, but their phenotypic relevance is often unclear. FOXP2 encodes a transcription factor with a forkhead box DNA-binding domain, but little is known about the functions of protein regions outside this domain. Methods We performed detailed functional analyses of seven rare FOXP2 variants found in affected cases, including three which have not been previously characterized, testing intracellular localization, transcriptional regulation, dimerization, and interaction with other proteins. To shed further light on molecular functions of FOXP2, we characterized the interaction between this transcription factor and co-repressor proteins of the C-terminal binding protein (CTBP) family. Finally, we analysed the functional significance of the polyglutamine tracts in FOXP2, since tract length variations have been reported in cases of neurodevelopmental disorder. Results We confirmed etiological roles of multiple FOXP2 variants. Of three variants that have been suggested to cause speech/language disorder, but never before been characterized, only one showed functional effects. For the other two, we found no effects on protein function in any assays, suggesting that they are incidental to the phenotype. We identified a CTBP-binding region within the N-terminal portion of FOXP2. This region includes two amino acid substitutions that occurred on the human lineage following the split from chimpanzees. However, we did not observe any effects of these amino acid changes on CTBP binding or other core aspects of FOXP2 function. Finally, we found that FOXP2 variants with reduced polyglutamine tracts did not exhibit altered behaviour in cellular assays, indicating that such tracts are non-essential for core aspects of FOXP2 function, and that tract variation is unlikely to be a highly penetrant cause of speech/language disorder. Conclusions Our findings highlight the importance of functional characterization of novel rare variants in FOXP2 in assessing the contribution of such variants to speech/language disorder and provide further insights into the molecular function of the FOXP2 protein. Electronic supplementary material The online version of this article (doi:10.1186/s11689-016-9177-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sara B Estruch
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Wundtlaan 1, 6525 XD Nijmegen, the Netherlands
| | - Sarah A Graham
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Wundtlaan 1, 6525 XD Nijmegen, the Netherlands
| | - Swathi M Chinnappa
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Wundtlaan 1, 6525 XD Nijmegen, the Netherlands
| | - Pelagia Deriziotis
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Wundtlaan 1, 6525 XD Nijmegen, the Netherlands
| | - Simon E Fisher
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Wundtlaan 1, 6525 XD Nijmegen, the Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 EN Nijmegen, the Netherlands
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Shimada MK, Sanbonmatsu R, Yamaguchi-Kabata Y, Yamasaki C, Suzuki Y, Chakraborty R, Gojobori T, Imanishi T. Selection pressure on human STR loci and its relevance in repeat expansion disease. Mol Genet Genomics 2016; 291:1851-69. [PMID: 27290643 DOI: 10.1007/s00438-016-1219-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Accepted: 05/21/2016] [Indexed: 12/30/2022]
Abstract
Short Tandem Repeats (STRs) comprise repeats of one to several base pairs. Because of the high mutability due to strand slippage during DNA synthesis, rapid evolutionary change in the number of repeating units directly shapes the range of repeat-number variation according to selection pressure. However, the remaining questions include: Why are STRs causing repeat expansion diseases maintained in the human population; and why are these limited to neurodegenerative diseases? By evaluating the genome-wide selection pressure on STRs using the database we constructed, we identified two different patterns of relationship in repeat-number polymorphisms between DNA and amino-acid sequences, although both patterns are evolutionary consequences of avoiding the formation of harmful long STRs. First, a mixture of degenerate codons is represented in poly-proline (poly-P) repeats. Second, long poly-glutamine (poly-Q) repeats are favored at the protein level; however, at the DNA level, STRs encoding long poly-Qs are frequently divided by synonymous SNPs. Furthermore, significant enrichments of apoptosis and neurodevelopment were biological processes found specifically in genes encoding poly-Qs with repeat polymorphism. This suggests the existence of a specific molecular function for polymorphic and/or long poly-Q stretches. Given that the poly-Qs causing expansion diseases were longer than other poly-Qs, even in healthy subjects, our results indicate that the evolutionary benefits of long and/or polymorphic poly-Q stretches outweigh the risks of long CAG repeats predisposing to pathological hyper-expansions. Molecular pathways in neurodevelopment requiring long and polymorphic poly-Q stretches may provide a clue to understanding why poly-Q expansion diseases are limited to neurodegenerative diseases.
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Affiliation(s)
- Makoto K Shimada
- Institute for Comprehensive Medical Science, Fujita Health University, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi, 470-1192, Japan. .,National Institute of Advanced Industrial Science and Technology, 2-3-26 Aomi Koto-ku, Tokyo, 135-0064, Japan. .,Japan Biological Informatics Consortium, 10F TIME24 Building, 2-4-32 Aomi, Koto-ku, Tokyo, 135-8073, Japan.
| | - Ryoko Sanbonmatsu
- Japan Biological Informatics Consortium, 10F TIME24 Building, 2-4-32 Aomi, Koto-ku, Tokyo, 135-8073, Japan
| | - Yumi Yamaguchi-Kabata
- National Institute of Advanced Industrial Science and Technology, 2-3-26 Aomi Koto-ku, Tokyo, 135-0064, Japan.,Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
| | - Chisato Yamasaki
- National Institute of Advanced Industrial Science and Technology, 2-3-26 Aomi Koto-ku, Tokyo, 135-0064, Japan.,Japan Biological Informatics Consortium, 10F TIME24 Building, 2-4-32 Aomi, Koto-ku, Tokyo, 135-8073, Japan
| | - Yoshiyuki Suzuki
- Graduate School of Natural Sciences, Nagoya City University, 1 Yamanohata, Mizuho-cho, Mizuho-ku, Nagoya, Aichi, 467-8501, Japan
| | - Ranajit Chakraborty
- Health Science Center, University of North Texas, 3500 Camp Bowie Blvd., Fort Worth, TX, 76107, USA
| | - Takashi Gojobori
- National Institute of Advanced Industrial Science and Technology, 2-3-26 Aomi Koto-ku, Tokyo, 135-0064, Japan.,Computational Bioscience Research Center, King Abdullah University of Science and Technology, Ibn Al-Haytham Building (West), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Tadashi Imanishi
- National Institute of Advanced Industrial Science and Technology, 2-3-26 Aomi Koto-ku, Tokyo, 135-0064, Japan.,Department of Molecular Life Science, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan
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15
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Pelassa I, Fiumara F. Differential Occurrence of Interactions and Interaction Domains in Proteins Containing Homopolymeric Amino Acid Repeats. Front Genet 2015; 6:345. [PMID: 26734058 PMCID: PMC4683181 DOI: 10.3389/fgene.2015.00345] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 11/20/2015] [Indexed: 12/13/2022] Open
Abstract
Homopolymeric amino acids repeats (AARs), which are widespread in proteomes, have often been viewed simply as spacers between protein domains, or even as "junk" sequences with no obvious function but with a potential to cause harm upon expansion as in genetic diseases associated with polyglutamine or polyalanine expansions, including Huntington disease and cleidocranial dysplasia. A growing body of evidence indicates however that at least some AARs can form organized, functional protein structures, and can regulate protein function. In particular, certain AARs can mediate protein-protein interactions, either through homotypic AAR-AAR contacts or through heterotypic contacts with other protein domains. It is still unclear however, whether AARs may have a generalized, proteome-wide role in shaping protein-protein interaction networks. Therefore, we have undertaken here a bioinformatics screening of the human proteome and interactome in search of quantitative evidence of such a role. We first identified the sets of proteins that contain repeats of any one of the 20 amino acids, as well as control sets of proteins chosen at random in the proteome. We then analyzed the connectivity between the proteins of the AAR-containing protein sets and we compared it with that observed in the corresponding control networks. We find evidence for different degrees of connectivity in the different AAR-containing protein networks. Indeed, networks of proteins containing polyglutamine, polyglutamate, polyproline, and other AARs show significantly increased levels of connectivity, whereas networks containing polyleucine and other hydrophobic repeats show lower degrees of connectivity. Furthermore, we observed that numerous protein-protein, -nucleic acid, and -lipid interaction domains are significantly enriched in specific AAR protein groups. These findings support the notion of a generalized, combinatorial role of AARs, together with conventional protein interaction domains, in shaping the interaction networks of the human proteome, and define proteome-wide knowledge that may guide the informed biological exploration of the role of AARs in protein interactions.
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Affiliation(s)
- Ilaria Pelassa
- Department of Neuroscience, University of Torino Torino, Italy
| | - Ferdinando Fiumara
- Department of Neuroscience, University of TorinoTorino, Italy; National Institute of Neuroscience (INN)Torino, Italy
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16
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Pelassa I, Corà D, Cesano F, Monje FJ, Montarolo PG, Fiumara F. Association of polyalanine and polyglutamine coiled coils mediates expansion disease-related protein aggregation and dysfunction. Hum Mol Genet 2014; 23:3402-20. [PMID: 24497578 PMCID: PMC4049302 DOI: 10.1093/hmg/ddu049] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The expansion of homopolymeric glutamine (polyQ) or alanine (polyA) repeats in certain proteins owing to genetic mutations induces protein aggregation and toxicity, causing at least 18 human diseases. PolyQ and polyA repeats can also associate in the same proteins, but the general extent of their association in proteomes is unknown. Furthermore, the structural mechanisms by which their expansion causes disease are not well understood, and these repeats are generally thought to misfold upon expansion into aggregation-prone β-sheet structures like amyloids. However, recent evidence indicates a critical role for coiled-coil (CC) structures in triggering aggregation and toxicity of polyQ-expanded proteins, raising the possibility that polyA repeats may as well form these structures, by themselves or in association with polyQ. We found through bioinformatics screenings that polyA, polyQ and polyQA repeats have a phylogenetically graded association in human and non-human proteomes and associate/overlap with CC domains. Circular dichroism and cross-linking experiments revealed that polyA repeats can form—alone or with polyQ and polyQA—CC structures that increase in stability with polyA length, forming higher-order multimers and polymers in vitro. Using structure-guided mutagenesis, we studied the relevance of polyA CCs to the in vivo aggregation and toxicity of RUNX2—a polyQ/polyA protein associated with cleidocranial dysplasia upon polyA expansion—and found that the stability of its polyQ/polyA CC controls its aggregation, localization and toxicity. These findings indicate that, like polyQ, polyA repeats form CC structures that can trigger protein aggregation and toxicity upon expansion in human genetic diseases.
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Affiliation(s)
| | - Davide Corà
- Center for Molecular Systems Biology, University of Torino, Torino 10123, Italy
| | - Federico Cesano
- Department of Chemistry, University of Torino, Torino 10125, Italy
| | - Francisco J. Monje
- Department of Neurophysiology and Neuropharmacology,Medical University of Vienna, Vienna 1090, Austria
| | - Pier Giorgio Montarolo
- Department of Neuroscience and
- National Institute of Neuroscience (INN), Torino 10125, Italy
| | - Ferdinando Fiumara
- Department of Neuroscience and
- To whom correspondence should be addressed at: Department of Neuroscience, University of Torino, Corso Raffaello 30, Torino 10125, Italy. Tel: +39-0116708486;
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