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Nyberg KG, Navales FG, Keles E, Nguyen JQ, Hertz LM, Carthew RW. Robust and heritable knockdown of gene expression using a self-cleaving ribozyme in Drosophila. Genetics 2024; 227:iyae067. [PMID: 38701221 PMCID: PMC11304983 DOI: 10.1093/genetics/iyae067] [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: 01/19/2024] [Revised: 04/11/2024] [Accepted: 04/20/2024] [Indexed: 05/05/2024] Open
Abstract
The current toolkit for genetic manipulation in the model animal Drosophila melanogaster is extensive and versatile but not without its limitations. Here, we report a powerful and heritable method to knockdown gene expression in D. melanogaster using the self-cleaving N79 hammerhead ribozyme, a modification of a naturally occurring ribozyme found in the parasite Schistosoma mansoni. A 111-bp ribozyme cassette, consisting of the N79 ribozyme surrounded by insulating spacer sequences, was inserted into 4 independent long noncoding RNA genes as well as the male-specific splice variant of doublesex using scarless CRISPR/Cas9-mediated genome editing. Ribozyme-induced RNA cleavage resulted in robust destruction of 3' fragments typically exceeding 90%. Single molecule RNA fluorescence in situ hybridization results suggest that cleavage and destruction can even occur for nascent transcribing RNAs. Knockdown was highly specific to the targeted RNA, with no adverse effects observed in neighboring genes or the other splice variants. To control for potential effects produced by the simple insertion of 111 nucleotides into genes, we tested multiple catalytically inactive ribozyme variants and found that a variant with scrambled N79 sequence best recapitulated natural RNA levels. Thus, self-cleaving ribozymes offer a novel approach for powerful gene knockdown in Drosophila, with potential applications for the study of noncoding RNAs, nuclear-localized RNAs, and specific splice variants of protein-coding genes.
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Affiliation(s)
- Kevin G Nyberg
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Fritz Gerald Navales
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Eren Keles
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Joseph Q Nguyen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Laura M Hertz
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Richard W Carthew
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
- NSF-Simons National Institute for Theory and Mathematics in Biology, Evanston, IL 60208, USA
- NSF-Simons Center for Quantitative Biology, Evanston, IL 60208, USA
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2
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Biswas S, Gurdziel K, Meller VH. siRNA that participates in Drosophila dosage compensation is produced by many 1.688X and 359 bp repeats. Genetics 2024; 227:iyae074. [PMID: 38718207 PMCID: PMC11228850 DOI: 10.1093/genetics/iyae074] [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: 12/19/2023] [Accepted: 04/29/2024] [Indexed: 07/09/2024] Open
Abstract
Organisms with differentiated sex chromosomes must accommodate unequal gene dosage in males and females. Male fruit flies increase X-linked gene expression to compensate for hemizygosity of their single X chromosome. Full compensation requires localization of the Male-Specific Lethal (MSL) complex to active genes on the male X, where it modulates chromatin to elevate expression. The mechanisms that identify X chromatin are poorly understood. The euchromatic X is enriched for AT-rich, ∼359 bp satellites termed the 1.688X repeats. Autosomal insertions of 1.688X DNA enable MSL recruitment to nearby genes. Ectopic expression of dsRNA from one of these repeats produces siRNA and partially restores X-localization of MSLs in males with defective X recognition. Surprisingly, expression of double-stranded RNA from three other 1.688X repeats failed to rescue males. We reconstructed dsRNA-expressing transgenes with sequence from two of these repeats and identified phasing of repeat DNA, rather than sequence or orientation, as the factor that determines rescue of males with defective X recognition. Small RNA sequencing revealed that siRNA was produced in flies with a transgene that rescues, but not in those carrying a transgene with the same repeat but different phasing. We demonstrate that pericentromeric X heterochromatin promotes X recognition through a maternal effect, potentially mediated by small RNA from closely related heterochromatic repeats. This suggests that the sources of siRNAs promoting X recognition are highly redundant. We propose that enrichment of satellite repeats on Drosophilid X chromosomes facilitates the rapid evolution of differentiated sex chromosomes by marking the X for compensation.
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Affiliation(s)
- Sudeshna Biswas
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA
| | - Katherine Gurdziel
- Department of Pharmacology, Wayne State University, Integrative Bioscience Center (iBio), 6135 Woodward, Detroit, MI 48202, USA
- Institute of Environmental Health Sciences, Wayne State University, Integrative Bioscience Center (iBio), 6135 Woodward, Detroit, MI 48202, USA
| | - Victoria H Meller
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA
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3
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Makki R, Meller VH. Identification of X chromatin is modulated by complementary pathways in Drosophila melanogaster. G3 (BETHESDA, MD.) 2024; 14:jkae057. [PMID: 38491905 PMCID: PMC11152068 DOI: 10.1093/g3journal/jkae057] [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: 08/04/2023] [Revised: 08/04/2023] [Accepted: 03/01/2024] [Indexed: 03/18/2024]
Abstract
Drosophila melanogaster males have one X chromosome while females have two. This creates an imbalance in X:A gene dosage between the sexes. This imbalance is corrected by increasing transcription from male X-linked genes approximately 2-fold. This process involves the Male-Specific Lethal (MSL) complex, which is recruited to Chromatin Entry Sites (CES) and transcribed X-linked genes, where it modifies chromatin to increase expression. Repetitive sequences strikingly enriched in X euchromatin, the 1.688X satellite repeats, also promote recruitment of the MSL complex to nearby genes. Unlike CES, the 1.688X repeats do not recruit the MSL complex directly. The genetic architecture of recruitment by these DNA elements remains speculative. To facilitate dissection of the mechanism of recruitment, we developed a luciferase reporter system for recruitment of compensation to an autosome. The system was validated by knock down of genes known to participate in compensation. Knock down of factors genetically linked to X recognition reveals that 1.688X repeats recruit through a different mechanism than the CES. Our findings suggest that 1.688X repeats play a larger role during embryogenesis, whereas the contribution of 1.688X repeats and CES is equivalent later in development. Our studies also reveal unexpected complexity and potential interdependence of recruiting elements.
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Affiliation(s)
- Reem Makki
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA
| | - Victoria H Meller
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA
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4
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Santinello B, Sun R, Amjad A, Hoyt SJ, Ouyang L, Courret C, Drennan R, Leo L, Larracuente AM, Core L, O'Neill RJ, Mellone BG. Transcription of a centromere-enriched retroelement and local retention of its RNA are significant features of the CENP-A chromatin landscape. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.14.574223. [PMID: 38293134 PMCID: PMC10827089 DOI: 10.1101/2024.01.14.574223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Centromeres depend on chromatin containing the conserved histone H3 variant CENP-A for function and inheritance, while the role of centromeric DNA repeats remains unclear. Retroelements are prevalent at centromeres across taxa and represent a potential mechanism for promoting transcription to aid in CENP-A incorporation or for generating RNA transcripts to maintain centromere integrity. Here, we probe into the transcription and RNA localization of the centromere-enriched retroelement G2/Jockey-3 (hereafter referred to as Jockey-3 ) in Drosophila melanogaster , currently the only in vivo model with assembled centromeres. We find that Jockey-3 is a major component of the centromeric transcriptome and produces RNAs that localize to centromeres in metaphase. Leveraging the polymorphism of Jockey-3 and a de novo centromere system, we show that these RNAs remain associated with their cognate DNA sequences in cis , suggesting they are unlikely to perform a sequence-specific function at all centromeres. We show that Jockey-3 transcription is positively correlated with the presence of CENP-A, and that recent Jockey-3 transposition events have occurred preferentially at CENP-A-containing chromatin. We propose that Jockey-3 contributes to the epigenetic maintenance of centromeres by promoting chromatin transcription, while inserting preferentially within these regions, selfishly ensuring its continued expression and transmission. Given the conservation of retroelements as centromere components through evolution, our findings have broad implications in understanding this association in other species.
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5
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Salzler HR, Vandadi V, Matera AG. Set2 and H3K36 regulate the Drosophila male X chromosome in a context-specific manner, independent from MSL complex spreading. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.03.592390. [PMID: 38766267 PMCID: PMC11100620 DOI: 10.1101/2024.05.03.592390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Dosage compensation in Drosophila involves upregulating male X-genes two-fold. This process is carried out by the MSL (male-specific lethal) complex, which binds high-affinity sites and spreads to surrounding genes. Current models of MSL spreading focus on interactions of MSL3 (male-specific lethal 3) with histone marks; in particular, Set2-dependent H3 lysine-36 trimethylation (H3K36me3). However, Set2 might affect DC via another target, or there could be redundancy between canonical H3.2 and variant H3.3 histones. Further, it is difficult to parse male-specific effects from those that are simply X-specific. To discriminate among these possibilities, we employed genomic approaches in H3K36 (residue) and Set2 (writer) mutants. The results confirm a role for Set2 in X-gene regulation, but show that expression trends in males are often mirrored in females. Instead of global male-specific reduction of X-genes in Set2/H3K36 mutants, the effects were heterogeneous. We identified cohorts of genes whose expression was significantly altered following loss of H3K36 or Set2, but the changes were in opposite directions, suggesting that H3K36me states have reciprocal functions. In contrast to H4K16R controls, analysis of combined H3.2K36R/H3.3K36R mutants neither showed consistent reduction in X-gene expression, nor any correlation with MSL3 binding. Examination of other developmental stages/tissues revealed additional layers of context-dependence. Our studies implicate BEAF-32 and other insulator proteins in Set2/H3K36-dependent regulation. Overall, the data are inconsistent with the prevailing model wherein H3K36me3 directly recruits the MSL complex. We propose that Set2 and H3K36 support DC indirectly, via processes that are utilized by MSL but common to both sexes.
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Affiliation(s)
- Harmony R. Salzler
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
| | - Vasudha Vandadi
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
| | - A. Gregory Matera
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA
- RNA Discovery and Lineberger Comprehensive Cancer Centers, University of North Carolina, Chapel Hill, NC, USA
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6
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Tikhonova EA, Georgiev PG, Maksimenko OG. Functional Role of C-terminal Domains in the MSL2 Protein of Drosophila melanogaster. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:663-673. [PMID: 38831503 DOI: 10.1134/s0006297924040060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 12/11/2023] [Accepted: 12/12/2023] [Indexed: 06/05/2024]
Abstract
Dosage compensation complex (DCC), which consists of five proteins and two non-coding RNAs roX, specifically binds to the X chromosome in males, providing a higher level of gene expression necessary to compensate for the monosomy of the sex chromosome in male Drosophila compared to the two X chromosomes in females. The MSL2 protein contains the N-terminal RING domain, which acts as an E3 ligase in ubiquitination of proteins and is the only subunit of the complex expressed only in males. Functional role of the two C-terminal domains of the MSL2 protein, enriched with proline (P-domain) and basic amino acids (B-domain), was investigated. As a result, it was shown that the B-domain destabilizes the MSL2 protein, which is associated with the presence of two lysines ubiquitination of which is under control of the RING domain of MSL2. The unstructured proline-rich domain stimulates transcription of the roX2 gene, which is necessary for effective formation of the dosage compensation complex.
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Affiliation(s)
| | - Pavel G Georgiev
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Oksana G Maksimenko
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
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7
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Hopkins BR, Angus-Henry A, Kim BY, Carlisle JA, Thompson A, Kopp A. Decoupled evolution of the Sex Peptide gene family and Sex Peptide Receptor in Drosophilidae. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.29.547128. [PMID: 37425821 PMCID: PMC10327216 DOI: 10.1101/2023.06.29.547128] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Across internally fertilising species, males transfer ejaculate proteins that trigger wide-ranging changes in female behaviour and physiology. Much theory has been developed to explore the drivers of ejaculate protein evolution. The accelerating availability of high-quality genomes now allows us to test how these proteins are evolving at fine taxonomic scales. Here, we use genomes from 264 species to chart the evolutionary history of Sex Peptide (SP), a potent regulator of female post-mating responses in Drosophila melanogaster. We infer that SP first evolved in the Drosophilinae subfamily and has followed markedly different evolutionary trajectories in different lineages. Outside of the Sophophora-Lordiphosa, SP exists largely as a single-copy gene with independent losses in several lineages. Within the Sophophora-Lordiphosa, the SP gene family has repeatedly and independently expanded. Up to seven copies, collectively displaying extensive sequence variation, are present in some species. Despite these changes, SP expression remains restricted to the male reproductive tract. Alongside, we document considerable interspecific variation in the presence and morphology of seminal microcarriers that, despite the critical role SP plays in microcarrier assembly in D. melanogaster, appear to be independent of changes in the presence/absence or sequence of SP. We end by providing evidence that SP's evolution is decoupled from that of its receptor, SPR, in which we detect no evidence of correlated diversifying selection. Collectively, our work describes the divergent evolutionary trajectories that a novel gene has taken following its origin and finds a surprisingly weak coevolutionary signal between a supposedly sexually antagonistic protein and its receptor.
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Affiliation(s)
- Ben R. Hopkins
- Department of Evolution and Ecology, University of California – Davis, CA, USA
| | - Aidan Angus-Henry
- Department of Evolution and Ecology, University of California – Davis, CA, USA
| | | | - Jolie A. Carlisle
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Ammon Thompson
- Department of Evolution and Ecology, University of California – Davis, CA, USA
| | - Artyom Kopp
- Department of Evolution and Ecology, University of California – Davis, CA, USA
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8
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Ahmed OM, Crocker A, Murthy M. Transcriptional profiling of Drosophila male-specific P1 (pC1) neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.07.566045. [PMID: 37986870 PMCID: PMC10659367 DOI: 10.1101/2023.11.07.566045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
In Drosophila melanogaster, the P1 (pC1) cluster of male-specific neurons both integrates sensory cues and drives or modulates behavioral programs such as courtship, in addition to contributing to a social arousal state. The behavioral function of these neurons is linked to the genes they express, which underpin their capacity for synaptic signaling, neuromodulation, and physiology. Yet, P1 (pC1) neurons have not been fully characterized at the transcriptome level. Moreover, it is unknown how the molecular landscape of P1 (pC1) neurons acutely changes after flies engage in social behaviors, where baseline P1 (pC1) neural activity is expected to increase. To address these two gaps, we use single cell-type RNA sequencing to profile and compare the transcriptomes of P1 (pC1) neurons harvested from socially paired versus solitary male flies. Compared to control transcriptome datasets, we find that P1 (pC1) neurons are enriched in 2,665 genes, including those encoding receptors, neuropeptides, and cell-adhesion molecules (dprs/DIPs). Furthermore, courtship is characterized by changes in ~300 genes, including those previously implicated in regulating behavior (e.g. DopEcR, Octβ3R, Fife, kairos, rad). Finally, we identify a suite of genes that link conspecific courtship with the innate immune system. Together, these data serve as a molecular map for future studies of an important set of higher-order and sexually-dimorphic neurons.
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Affiliation(s)
- Osama M Ahmed
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08540, USA
- Department of Psychology, University of Washington, Seattle, WA 98105, USA
| | - Amanda Crocker
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08540, USA
- Program in Neuroscience, Middlebury College, Middlebury, VT 05753, USA
| | - Mala Murthy
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08540, USA
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Jalloh B, Lancaster CL, Rounds JC, Brown BE, Leung SW, Banerjee A, Morton DJ, Bienkowski RS, Fasken MB, Kremsky IJ, Tegowski M, Meyer K, Corbett A, Moberg K. The Drosophila Nab2 RNA binding protein inhibits m 6A methylation and male-specific splicing of Sex lethal transcript in female neuronal tissue. eLife 2023; 12:e64904. [PMID: 37458420 PMCID: PMC10351920 DOI: 10.7554/elife.64904] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Accepted: 06/23/2023] [Indexed: 07/20/2023] Open
Abstract
The Drosophila polyadenosine RNA binding protein Nab2, which is orthologous to a human protein lost in a form of inherited intellectual disability, controls adult locomotion, axon projection, dendritic arborization, and memory through a largely undefined set of target RNAs. Here, we show a specific role for Nab2 in regulating splicing of ~150 exons/introns in the head transcriptome and focus on retention of a male-specific exon in the sex determination factor Sex-lethal (Sxl) that is enriched in female neurons. Previous studies have revealed that this splicing event is regulated in females by N6-methyladenosine (m6A) modification by the Mettl3 complex. At a molecular level, Nab2 associates with Sxl pre-mRNA in neurons and limits Sxl m6A methylation at specific sites. In parallel, reducing expression of the Mettl3, Mettl3 complex components, or the m6A reader Ythdc1 rescues mutant phenotypes in Nab2 flies. Overall, these data identify Nab2 as an inhibitor of m6A methylation and imply significant overlap between Nab2 and Mettl3 regulated RNAs in neuronal tissue.
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Affiliation(s)
- Binta Jalloh
- Department of Biology, Emory UniversityAtlantaUnited States
- Department of Cell Biology Emory University School of MedicineAtlantaUnited States
- Graduate Program in Genetics and Molecular Biology, Emory UniversityAtlantaUnited States
| | - Carly L Lancaster
- Department of Biology, Emory UniversityAtlantaUnited States
- Department of Cell Biology Emory University School of MedicineAtlantaUnited States
- Graduate Program in Biochemistry, Cell and Developmental Biology, Emory UniversityAtlantaUnited States
| | - J Christopher Rounds
- Department of Biology, Emory UniversityAtlantaUnited States
- Department of Cell Biology Emory University School of MedicineAtlantaUnited States
- Graduate Program in Genetics and Molecular Biology, Emory UniversityAtlantaUnited States
| | - Brianna E Brown
- Department of Biology, Emory UniversityAtlantaUnited States
- Department of Cell Biology Emory University School of MedicineAtlantaUnited States
| | - Sara W Leung
- Department of Biology, Emory UniversityAtlantaUnited States
| | - Ayan Banerjee
- Department of Biology, Emory UniversityAtlantaUnited States
| | - Derrick J Morton
- Department of Biology, Emory UniversityAtlantaUnited States
- Emory Institutional Research and Academic Career Development Award (IRACDA), Fellowships in Research and Science Teaching (FIRST) Postdoctoral FellowshipAtlantaUnited States
| | - Rick S Bienkowski
- Department of Biology, Emory UniversityAtlantaUnited States
- Department of Cell Biology Emory University School of MedicineAtlantaUnited States
- Graduate Program in Genetics and Molecular Biology, Emory UniversityAtlantaUnited States
| | - Milo B Fasken
- Department of Biology, Emory UniversityAtlantaUnited States
| | | | - Matthew Tegowski
- Department of Biochemistry, Duke University School of MedicineDurhamUnited States
| | - Kate Meyer
- Department of Biochemistry, Duke University School of MedicineDurhamUnited States
- Department of Neurobiology, Duke University School of MedicineDurhamUnited States
| | - Anita Corbett
- Department of Biology, Emory UniversityAtlantaUnited States
| | - Ken Moberg
- Department of Cell Biology Emory University School of MedicineAtlantaUnited States
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10
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Thompson MK, Ceccarelli A, Ish-Horowicz D, Davis I. Dynamically regulated transcription factors are encoded by highly unstable mRNAs in the Drosophila larval brain. RNA (NEW YORK, N.Y.) 2023; 29:1020-1032. [PMID: 37041032 DOI: 10.1261/rna.079552.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 03/14/2023] [Indexed: 06/18/2023]
Abstract
The level of each RNA species depends on the balance between its rates of production and decay. Although previous studies have measured RNA decay across the genome in tissue culture and single-celled organisms, few experiments have been performed in intact complex tissues and organs. It is therefore unclear whether the determinants of RNA decay found in cultured cells are preserved in an intact tissue, and whether they differ between neighboring cell types and are regulated during development. To address these questions, we measured RNA synthesis and decay rates genome wide via metabolic labeling of whole cultured Drosophila larval brains using 4-thiouridine. Our analysis revealed that decay rates span a range of more than 100-fold, and that RNA stability is linked to gene function, with mRNAs encoding transcription factors being much less stable than mRNAs involved in core metabolic functions. Surprisingly, among transcription factor mRNAs there was a clear demarcation between more widely used transcription factors and those that are expressed only transiently during development. mRNAs encoding transient transcription factors are among the least stable in the brain. These mRNAs are characterized by epigenetic silencing in most cell types, as shown by their enrichment with the histone modification H3K27me3. Our data suggest the presence of an mRNA destabilizing mechanism targeted to these transiently expressed transcription factors to allow their levels to be regulated rapidly with high precision. Our study also demonstrates a general method for measuring mRNA transcription and decay rates in intact organs or tissues, offering insights into the role of mRNA stability in the regulation of complex developmental programs.
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Affiliation(s)
- Mary Kay Thompson
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Arianna Ceccarelli
- Mathematical Institute, University of Oxford, Oxford OX1 3LB, United Kingdom
| | - David Ish-Horowicz
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
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11
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Noncoding RNA Regulation of Hormonal and Metabolic Systems in the Fruit Fly Drosophila. Metabolites 2023; 13:metabo13020152. [PMID: 36837772 PMCID: PMC9967906 DOI: 10.3390/metabo13020152] [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: 12/16/2022] [Revised: 01/12/2023] [Accepted: 01/16/2023] [Indexed: 01/22/2023] Open
Abstract
The importance of RNAs is commonly recognised thanks to protein-coding RNAs, whereas non-coding RNAs (ncRNAs) were conventionally regarded as 'junk'. In the last decade, ncRNAs' significance and roles are becoming noticeable in various biological activities, including those in hormonal and metabolic regulation. Among the ncRNAs: microRNA (miRNA) is a small RNA transcript with ~20 nucleotides in length; long non-coding RNA (lncRNA) is an RNA transcript with >200 nucleotides; and circular RNA (circRNA) is derived from back-splicing of pre-mRNA. These ncRNAs can regulate gene expression levels at epigenetic, transcriptional, and post-transcriptional levels through various mechanisms in insects. A better understanding of these crucial regulators is essential to both basic and applied entomology. In this review, we intend to summarise and discuss the current understanding and knowledge of miRNA, lncRNA, and circRNA in the best-studied insect model, the fruit fly Drosophila.
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12
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Nanni AV, Martinez N, Graze R, Morse A, Newman JRB, Jain V, Vlaho S, Signor S, Nuzhdin SV, Renne R, McIntyre LM. Sex-biased expression is associated with chromatin state in D. melanogaster and D. simulans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.13.523946. [PMID: 36711631 PMCID: PMC9882225 DOI: 10.1101/2023.01.13.523946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We propose a new model for the association of chromatin state and sex-bias in expression. We hypothesize enrichment of open chromatin in the sex where we see expression bias (OS) and closed chromatin in the opposite sex (CO). In this study of D. melanogaster and D. simulans head tissue, sex-bias in expression is associated with H3K4me3 (open mark) in males for male-biased genes and in females for female-biased genes in both species. Sex-bias in expression is also largely conserved in direction and magnitude between the two species on the X and autosomes. In male-biased orthologs, the sex-bias ratio is more divergent between species if both species have H3K27me2me3 marks in females compared to when either or neither species has H3K27me2me3 in females. H3K27me2me3 marks in females are associated with male-bias in expression on the autosomes in both species, but on the X only in D. melanogaster . In female-biased orthologs the relationship between the species for the sex-bias ratio is similar regardless of the H3K27me2me3 marks in males. Female-biased orthologs are more similar in the ratio of sex-bias than male-biased orthologs and there is an excess of male-bias in expression in orthologs that gain/lose sex-bias. There is an excess of male-bias in sex-limited expression in both species suggesting excess male-bias is due to rapid evolution between the species. The X chromosome has an enrichment in male-limited H3K4me3 in both species and an enrichment of sex-bias in expression compared to the autosomes.
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Affiliation(s)
- Adalena V Nanni
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Natalie Martinez
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
| | - Rita Graze
- Department of Biological Sciences, Auburn University, Auburn, AL, USA
| | - Alison Morse
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Jeremy R B Newman
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Vaibhav Jain
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
| | - Srna Vlaho
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Sarah Signor
- Department of Biological Sciences, North Dakota State University, Fargo, ND, USA
| | - Sergey V Nuzhdin
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Rolf Renne
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Lauren M McIntyre
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
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13
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Zhang X, Wu X, Peng J, Sun A, Guo Y, Fu P, Gao G. Cis- and trans-regulation by histone H4 basic patch R17/R19 in metazoan development. Open Biol 2022; 12:220066. [PMID: 36382370 PMCID: PMC9667139 DOI: 10.1098/rsob.220066] [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] [Indexed: 11/18/2022] Open
Abstract
The histone H4 basic patch is critical for chromatin structure and regulation of the chromatin machinery. However, the biological roles of these positively charged residues and the mechanisms by which they regulate gene expression remain unclear. In this study, we used histone mutagenesis to investigate the physiological function and downstream regulatory genes of H4 residues R17 and R19 in Drosophila. We found all histone mutations including R17A/E/H and R19A/E/H (R17 and R19 of H4 are substituted by A, E and H respectively) result in a range of growth defects and abnormalities in chromosomal high-order structures, whereas R17E mutation is embryonic lethal. RNA-seq demonstrates that downregulated genes in both R17A and R19A show significant overlap and are enriched in development-related pathways. In addition, Western and cytological analyses showed that the R17A mutation resulted in a significant reduction in H4K16 acetylation and male offspring, implying that the R17 may be involved in male dosage compensation mechanisms. R19 mutation on the other hand strongly affect Gpp (Dot1 homologue in flies)-mediated H3K79 methylation, possibly through histone crosstalk. Together these results provide insights into the differential impacts of positive charges of H4 basic patch R17/R19 on regulation of gene transcription during developmental processes.
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Affiliation(s)
- Xuedi Zhang
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai 201210, People's Republic of China
| | - Xiangyu Wu
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai 201210, People's Republic of China
| | - Ju Peng
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai 201210, People's Republic of China
| | - Angyang Sun
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai 201210, People's Republic of China
| | - Yan Guo
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai 201210, People's Republic of China
| | - Pengchong Fu
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai 201210, People's Republic of China
| | - Guanjun Gao
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai 201210, People's Republic of China
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14
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Dosage Compensation in Drosophila: Its Canonical and Non-Canonical Mechanisms. Int J Mol Sci 2022; 23:ijms231810976. [PMID: 36142884 PMCID: PMC9506574 DOI: 10.3390/ijms231810976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/16/2022] [Accepted: 09/17/2022] [Indexed: 11/17/2022] Open
Abstract
Dosage compensation equalizes gene expression in a single male X chromosome with that in the pairs of autosomes and female X chromosomes. In the fruit fly Drosophila, canonical dosage compensation is implemented by the male-specific lethal (MSL) complex functioning in all male somatic cells. This complex contains acetyl transferase males absent on the first (MOF), which performs H4K16 hyperacetylation specifically in the male X chromosome, thus facilitating transcription of the X-linked genes. However, accumulating evidence points to an existence of additional, non-canonical dosage compensation mechanisms operating in somatic and germline cells. In this review, we discuss current advances in the understanding of both canonical and non-canonical mechanisms of dosage compensation in Drosophila.
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15
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Meisel RP, Asgari D, Schlamp F, Unckless RL. Induction and inhibition of Drosophila X chromosome gene expression are both impeded by the dosage compensation complex. G3 (BETHESDA, MD.) 2022; 12:6632659. [PMID: 35792851 PMCID: PMC9434221 DOI: 10.1093/g3journal/jkac165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 06/16/2022] [Indexed: 12/24/2022]
Abstract
Sex chromosomes frequently differ from the autosomes in the frequencies of genes with sexually dimorphic or tissue-specific expression. Multiple hypotheses have been put forth to explain the unique gene content of the X chromosome, including selection against male-beneficial X-linked alleles, expression limits imposed by the haploid dosage of the X in males, and interference by the dosage compensation complex on expression in males. Here, we investigate these hypotheses by examining differential gene expression in Drosophila melanogaster following several treatments that have widespread transcriptomic effects: bacterial infection, viral infection, and abiotic stress. We found that genes that are induced (upregulated) by these biotic and abiotic treatments are frequently under-represented on the X chromosome, but so are those that are repressed (downregulated) following treatment. We further show that whether a gene is bound by the dosage compensation complex in males can largely explain the paucity of both up- and downregulated genes on the X chromosome. Specifically, genes that are bound by the dosage compensation complex, or close to a dosage compensation complex high-affinity site, are unlikely to be up- or downregulated after treatment. This relationship, however, could partially be explained by a correlation between differential expression and breadth of expression across tissues. Nonetheless, our results suggest that dosage compensation complex binding, or the associated chromatin modifications, inhibit both up- and downregulation of X chromosome gene expression within specific contexts, including tissue-specific expression. We propose multiple possible mechanisms of action for the effect, including a role of Males absent on the first, a component of the dosage compensation complex, as a dampener of gene expression variance in both males and females. This effect could explain why the Drosophila X chromosome is depauperate in genes with tissue-specific or induced expression, while the mammalian X has an excess of genes with tissue-specific expression.
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Affiliation(s)
- Richard P Meisel
- Department of Biology and Biochemistry, University of Houston, 3455 Cullen Blvd, Houston, TX 77204-5001, USA
| | - Danial Asgari
- Department of Biology and Biochemistry, University of Houston, 3455 Cullen Blvd, Houston, TX 77204-5001, USA
| | - Florencia Schlamp
- Department of Medicine, NYU Grossman School of Medicine, 435 E 30th St, New York, NY 10016, USA
| | - Robert L Unckless
- Department of Molecular Biosciences, University of Kansas, 4055 Haworth Hall, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA
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16
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Cao H, Kapranov P. Methods to Analyze the Non-Coding RNA Interactome—Recent Advances and Challenges. Front Genet 2022; 13:857759. [PMID: 35368711 PMCID: PMC8969105 DOI: 10.3389/fgene.2022.857759] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 02/15/2022] [Indexed: 12/03/2022] Open
Abstract
Most of the human genome is transcribed to generate a multitude of non-coding RNAs. However, while these transcripts have generated an immense amount of scientific interest, their biological function remains a subject of an intense debate. Understanding mechanisms of action of non-coding RNAs is a key to addressing the issue of biological relevance of these transcripts. Based on some well-understood non-coding RNAs that function inside the cell by interacting with other molecules, it is generally believed many other non-coding transcripts could also function in a similar fashion. Therefore, development of methods that can map RNA interactome is the key to understanding functionality of the extensive cellular non-coding transcriptome. Here, we review the vast progress that has been made in the past decade in technologies that can map RNA interactions with different sites in DNA, proteins or other RNA molecules; the general approaches used to validate the existence of novel interactions; and the challenges posed by interpreting the data obtained using the interactome mapping methods.
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17
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McCarthy A, Sarkar K, Martin ET, Upadhyay M, Jang S, Williams ND, Forni PE, Buszczak M, Rangan P. Msl3 promotes germline stem cell differentiation in female Drosophila. Development 2022; 149:dev199625. [PMID: 34878097 PMCID: PMC8783043 DOI: 10.1242/dev.199625] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 11/19/2021] [Indexed: 01/07/2023]
Abstract
Gamete formation from germline stem cells (GSCs) is essential for sexual reproduction. However, the regulation of GSC differentiation is incompletely understood. Set2, which deposits H3K36me3 modifications, is required for GSC differentiation during Drosophila oogenesis. We discovered that the H3K36me3 reader Male-specific lethal 3 (Msl3) and histone acetyltransferase complex Ada2a-containing (ATAC) cooperate with Set2 to regulate GSC differentiation in female Drosophila. Msl3, acting independently of the rest of the male-specific lethal complex, promotes transcription of genes, including a germline-enriched ribosomal protein S19 paralog RpS19b. RpS19b upregulation is required for translation of RNA-binding Fox protein 1 (Rbfox1), a known meiotic cell cycle entry factor. Thus, Msl3 regulates GSC differentiation by modulating translation of a key factor that promotes transition to an oocyte fate.
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Affiliation(s)
- Alicia McCarthy
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12202, USA
| | - Kahini Sarkar
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12202, USA
| | - Elliot T. Martin
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12202, USA
| | - Maitreyi Upadhyay
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12202, USA
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
| | - Seoyeon Jang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Nathan D. Williams
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Paolo E. Forni
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12202, USA
| | - Michael Buszczak
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Prashanth Rangan
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12202, USA
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18
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Majane AC, Cridland JM, Begun DJ. Single-nucleus transcriptomes reveal evolutionary and functional properties of cell types in the Drosophila accessory gland. Genetics 2021; 220:6440054. [PMID: 34849871 DOI: 10.1093/genetics/iyab213] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/10/2021] [Indexed: 11/14/2022] Open
Abstract
Many traits responsible for male reproduction evolve quickly, including gene expression phenotypes in germline and somatic male reproductive tissues. Rapid male evolution in polyandrous species is thought to be driven by competition among males for fertilizations and conflicts between male and female fitness interests that manifest in post-copulatory phenotypes. In Drosophila, seminal fluid proteins secreted by three major cell types of the male accessory gland and ejaculatory duct are required for female sperm storage and use, and influence female post-copulatory traits. Recent work has shown that these cell types have overlapping but distinct effects on female post-copulatory biology, yet relatively little is known about their evolutionary properties. Here we use single-nucleus RNA-Seq of the accessory gland and ejaculatory duct from Drosophila melanogaster and two closely related species to comprehensively describe the cell diversity of these tissues and their transcriptome evolution for the first time. We find that seminal fluid transcripts are strongly partitioned across the major cell types, and expression of many other genes additionally define each cell type. We also report previously undocumented diversity in main cells. Transcriptome divergence was found to be heterogeneous across cell types and lineages, revealing a complex evolutionary process. Furthermore, protein adaptation varied across cell types, with potential consequences for our understanding of selection on male post-copulatory traits.
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Affiliation(s)
- Alex C Majane
- Department of Evolution and Ecology, University of California - Davis, Davis, CA 95616, USA
| | - Julie M Cridland
- Department of Evolution and Ecology, University of California - Davis, Davis, CA 95616, USA
| | - David J Begun
- Department of Evolution and Ecology, University of California - Davis, Davis, CA 95616, USA
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19
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Lakhotia SC. Dosage compensation in Drosophila in the 1960s: a personal historical perspective. J Genet 2021. [DOI: 10.1007/s12041-021-01322-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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20
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Villa R, Jagtap PKA, Thomae AW, Campos Sparr A, Forné I, Hennig J, Straub T, Becker PB. Divergent evolution toward sex chromosome-specific gene regulation in Drosophila. Genes Dev 2021; 35:1055-1070. [PMID: 34140353 PMCID: PMC8247607 DOI: 10.1101/gad.348411.121] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 05/04/2021] [Indexed: 02/07/2023]
Abstract
The dosage compensation complex (DCC) of Drosophila identifies its X-chromosomal binding sites with exquisite selectivity. The principles that assure this vital targeting are known from the D. melanogaster model: DCC-intrinsic specificity of DNA binding, cooperativity with the CLAMP protein, and noncoding roX2 RNA transcribed from the X chromosome. We found that in D. virilis, a species separated from melanogaster by 40 million years of evolution, all principles are active but contribute differently to X specificity. In melanogaster, the DCC subunit MSL2 evolved intrinsic DNA-binding selectivity for rare PionX sites, which mark the X chromosome. In virilis, PionX motifs are abundant and not X-enriched. Accordingly, MSL2 lacks specific recognition. Here, roX2 RNA plays a more instructive role, counteracting a nonproductive interaction of CLAMP and modulating DCC binding selectivity. Remarkably, roX2 triggers a stable chromatin binding mode characteristic of DCC. Evidently, X-specific regulation is achieved by divergent evolution of protein, DNA, and RNA components.
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Affiliation(s)
- Raffaella Villa
- Molecular Biology Division, Biomedical Center, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Pravin Kumar Ankush Jagtap
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Andreas W Thomae
- Molecular Biology Division, Biomedical Center, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany.,Core Facility Bioimaging, Biomedical Center, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Aline Campos Sparr
- Molecular Biology Division, Biomedical Center, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Ignasi Forné
- Protein Analysis Unit, Biomedical Center, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Janosch Hennig
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Tobias Straub
- Bioinformatics Unit, Biomedical Center, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Peter B Becker
- Molecular Biology Division, Biomedical Center, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
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21
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Senmatsu S, Hirota K. Roles of lncRNA transcription as a novel regulator of chromosomal function. Genes Genet Syst 2020; 95:213-223. [PMID: 33028747 DOI: 10.1266/ggs.20-00024] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In recent years, many transcriptome analyses have revealed that numerous noncoding RNAs are transcribed in eukaryotic cells. Long noncoding RNAs (lncRNAs), which consist of over 200 nucleotides, are considered to be key players in a variety of biological processes and structures including gene expression, differentiation and nuclear architecture. Many studies on individual lncRNAs have identified their molecular functions as decoys, recruiters and scaffolds, which arise through interactions with proteins and the construction of ribonucleoproteins. In addition to the roles played by transcribed lncRNA molecules, several studies have indicated the important functions of nascent lncRNA transcription processes. In this review, we discuss recent findings on the important roles of lncRNA transcription processes in the regulation of chromosome function.
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Affiliation(s)
- Satoshi Senmatsu
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University
| | - Kouji Hirota
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University
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22
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Tikhonova E, Fedotova A, Bonchuk A, Mogila V, Larschan EN, Georgiev P, Maksimenko O. The simultaneous interaction of MSL2 with CLAMP and DNA provides redundancy in the initiation of dosage compensation in Drosophila males. Development 2019; 146:dev.179663. [PMID: 31320325 DOI: 10.1242/dev.179663] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/05/2019] [Indexed: 12/16/2022]
Abstract
The binding of the Drosophila male-specific lethal dosage compensation complex (DCC) exclusively to the male X chromosome provides an excellent model system to understand mechanisms of selective recruitment of protein complexes to chromatin. Previous studies showed that the male-specific organizer of the complex, MSL2, and the ubiquitous DNA-binding protein CLAMP are key players in the specificity of X chromosome binding. The CXC domain of MSL2 binds to genomic sites of DCC recruitment in vitro Another conserved domain of MSL2, named Clamp-binding domain (CBD) directly interacts with the N-terminal zinc-finger domain of CLAMP. Here, we found that inactivation of CBD or CXC individually only modestly affected recruitment of the DCC to the X chromosome in males. However, combination of these two genetic lesions within the same MSL2 mutant resulted in an increased loss of DCC recruitment to the X chromosome. Thus, proper MSL2 positioning requires an interaction with either CLAMP or DNA to initiate dosage compensation in Drosophila males.
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Affiliation(s)
- Evgeniya Tikhonova
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Anna Fedotova
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Artem Bonchuk
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Vladic Mogila
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Erica N Larschan
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Oksana Maksimenko
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
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23
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Prayitno K, Schauer T, Regnard C, Becker PB. Progressive dosage compensation during Drosophila embryogenesis is reflected by gene arrangement. EMBO Rep 2019; 20:e48138. [PMID: 31286660 PMCID: PMC6680166 DOI: 10.15252/embr.201948138] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 06/07/2019] [Accepted: 06/18/2019] [Indexed: 12/24/2022] Open
Abstract
In Drosophila melanogaster males, X-chromosome monosomy is compensated by chromosome-wide transcription activation. We found that complete dosage compensation during embryogenesis takes surprisingly long and is incomplete even after 10 h of development. Although the activating dosage compensation complex (DCC) associates with the X-chromosome and MOF acetylates histone H4 early, many genes are not compensated. Acetylation levels on gene bodies continue to increase for several hours after gastrulation in parallel with progressive compensation. Constitutive genes are compensated earlier than developmental genes. Remarkably, later compensation correlates with longer distances to DCC binding sites. This time-space relationship suggests that DCC action on target genes requires maturation of the active chromosome compartment.
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Affiliation(s)
- Khairunnadiya Prayitno
- Molecular Biology DivisionBiomedical CenterLudwig‐Maximilians‐UniversityMunichGermany
- Graduate School of Quantitative Biosciences MunichLudwig‐Maximilians‐UniversityMunichGermany
| | - Tamás Schauer
- Molecular Biology DivisionBiomedical CenterLudwig‐Maximilians‐UniversityMunichGermany
- Bioinformatics UnitBiomedical CenterLudwig‐Maximilians‐UniversityMunichGermany
| | - Catherine Regnard
- Molecular Biology DivisionBiomedical CenterLudwig‐Maximilians‐UniversityMunichGermany
| | - Peter B Becker
- Molecular Biology DivisionBiomedical CenterLudwig‐Maximilians‐UniversityMunichGermany
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24
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Bhardwaj V, Semplicio G, Erdogdu NU, Manke T, Akhtar A. MAPCap allows high-resolution detection and differential expression analysis of transcription start sites. Nat Commun 2019; 10:3219. [PMID: 31363093 PMCID: PMC6667505 DOI: 10.1038/s41467-019-11115-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 06/20/2019] [Indexed: 01/06/2023] Open
Abstract
The position, shape and number of transcription start sites (TSS) are critical determinants of gene regulation. Most methods developed to detect TSSs and study promoter usage are, however, of limited use in studies that demand quantification of expression changes between two or more groups. In this study, we combine high-resolution detection of transcription start sites and differential expression analysis using a simplified TSS quantification protocol, MAPCap (Multiplexed Affinity Purification of Capped RNA) along with the software icetea. Applying MAPCap on developing Drosophila melanogaster embryos and larvae, we detected stage and sex-specific promoter and enhancer activity and quantify the effect of mutants of maleless (MLE) helicase at X-chromosomal promoters. We observe that MLE mutation leads to a median 1.9 fold drop in expression of X-chromosome promoters and affects the expression of several TSSs with a sexually dimorphic expression on autosomes. Our results provide quantitative insights into promoter activity during dosage compensation. The position, shape and number of transcription start sites (TSS) regulate gene expression. Here authors present MAPCap, a method for high-resolution detection and differential expression analysis of TSS, and apply MAPCap to early fly development, detecting stage and sex-specific promoter and enhancer activity.
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Affiliation(s)
- Vivek Bhardwaj
- Max Planck Institute for Immunobiology and Epigenetics, 79108, Freiburg, Germany.,Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Giuseppe Semplicio
- Max Planck Institute for Immunobiology and Epigenetics, 79108, Freiburg, Germany
| | - Niyazi Umut Erdogdu
- Max Planck Institute for Immunobiology and Epigenetics, 79108, Freiburg, Germany.,Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Thomas Manke
- Max Planck Institute for Immunobiology and Epigenetics, 79108, Freiburg, Germany
| | - Asifa Akhtar
- Max Planck Institute for Immunobiology and Epigenetics, 79108, Freiburg, Germany.
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25
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Andrew DJ, Chen EH, Manoli DS, Ryner LC, Arbeitman MN. Sex and the Single Fly: A Perspective on the Career of Bruce S. Baker. Genetics 2019; 212:365-376. [PMID: 31167898 PMCID: PMC6553822 DOI: 10.1534/genetics.119.301928] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 04/01/2019] [Indexed: 11/18/2022] Open
Abstract
Bruce Baker, a preeminent Drosophila geneticist who made fundamental contributions to our understanding of the molecular genetic basis of sex differences, passed away July 1, 2018 at the age of 72. Members of Bruce's laboratory remember him as an intensely dedicated, rigorous, creative, deep-thinking, and fearless scientist. His trainees also remember his strong commitment to teaching students at every level. Bruce's career studying sex differences had three major epochs, where the laboratory was focused on: (1) sex determination and dosage compensation, (2) the development of sex-specific structures, and (3) the molecular genetic basis for sex differences in behavior. Several members of the Baker laboratory have come together to honor Bruce by highlighting some of the laboratory's major scientific contributions in these areas.
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Affiliation(s)
- Deborah J Andrew
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Elizabeth H Chen
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Devanand S Manoli
- Department of Psychiatry, University of California, San Francisco, California 94158
- Weill Institute for Neuroscience, Center for Integrative Neuroscience, University of California, San Francisco, California 94158
| | - Lisa C Ryner
- Development Sciences Division, Roche Genentech, South San Francisco, California 94080
| | - Michelle N Arbeitman
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306
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26
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Machyna M, Simon MD. Catching RNAs on chromatin using hybridization capture methods. Brief Funct Genomics 2019; 17:96-103. [PMID: 29126220 DOI: 10.1093/bfgp/elx038] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The growing appreciation of the importance of long noncoding RNAs (lncRNAs), together with the awareness that some of these RNAs are associated with chromatin, has inspired the development of methods to detect their sites of interaction on a genome-wide scale at high resolution. Hybridization capture methods combine antisense oligonucleotide hybridization with enrichment of RNA from cross-linked chromatin extracts. These techniques have provided insight into lncRNA localization and the interactions of lncRNAs with protein to better understand biological roles of lncRNAs. Here, we review the core principles of hybridization capture methods, focusing on the three most commonly used protocols: capture hybridization analysis of RNA targets (CHART), chromatin isolation by RNA purification (ChIRP) and RNA affinity purification (RAP). We highlight the general principles of these techniques and discuss how differences in experimental procedures present distinct challenges to help researchers using these protocols or, more generally, interpreting the results of hybridization capture experiments.
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27
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Kim M, Faucillion ML, Larsson J. RNA-on-X 1 and 2 in Drosophila melanogaster fulfill separate functions in dosage compensation. PLoS Genet 2018; 14:e1007842. [PMID: 30532158 PMCID: PMC6301720 DOI: 10.1371/journal.pgen.1007842] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 12/20/2018] [Accepted: 11/20/2018] [Indexed: 02/03/2023] Open
Abstract
In Drosophila melanogaster, the male-specific lethal (MSL) complex plays a key role in dosage compensation by stimulating expression of male X-chromosome genes. It consists of MSL proteins and two long noncoding RNAs, roX1 and roX2, that are required for spreading of the complex on the chromosome and are redundant in the sense that loss of either does not affect male viability. However, despite rapid evolution, both roX species are present in diverse Drosophilidae species, raising doubts about their full functional redundancy. Thus, we have investigated consequences of deleting roX1 and/or roX2 to probe their specific roles and redundancies in D. melanogaster. We have created a new mutant allele of roX2 and show that roX1 and roX2 have partly separable functions in dosage compensation. In larvae, roX1 is the most abundant variant and the only variant present in the MSL complex when the complex is transmitted (physically associated with the X-chromosome) in mitosis. Loss of roX1 results in reduced expression of the genes on the X-chromosome, while loss of roX2 leads to MSL-independent upregulation of genes with male-biased testis-specific transcription. In roX1 roX2 mutant, gene expression is strongly reduced in a manner that is not related to proximity to high-affinity sites. Our results suggest that high tolerance of mis-expression of the X-chromosome has evolved. We propose that this may be a common property of sex-chromosomes, that dosage compensation is a stochastic process and its precision for each individual gene is regulated by the density of high-affinity sites in the locus.
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Affiliation(s)
- Maria Kim
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | | | - Jan Larsson
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- * E-mail:
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Facultative dosage compensation of developmental genes on autosomes in Drosophila and mouse embryonic stem cells. Nat Commun 2018; 9:3626. [PMID: 30194291 PMCID: PMC6128902 DOI: 10.1038/s41467-018-05642-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 07/04/2018] [Indexed: 12/25/2022] Open
Abstract
Haploinsufficiency and aneuploidy are two phenomena, where gene dosage alterations cause severe defects ultimately resulting in developmental failures and disease. One remarkable exception is the X chromosome, where copy number differences between sexes are buffered by dosage compensation systems. In Drosophila, the Male-Specific Lethal complex (MSLc) mediates upregulation of the single male X chromosome. The evolutionary origin and conservation of this process orchestrated by MSL2, the only male-specific protein within the fly MSLc, have remained unclear. Here, we report that MSL2, in addition to regulating the X chromosome, targets autosomal genes involved in patterning and morphogenesis. Precise regulation of these genes by MSL2 is required for proper development. This set of dosage-sensitive genes maintains such regulation during evolution, as MSL2 binds and similarly regulates mouse orthologues via Histone H4 lysine 16 acetylation. We propose that this gene-by-gene dosage compensation mechanism was co-opted during evolution for chromosome-wide regulation of the Drosophila male X. In Drosophila the Male-Specific Lethal complex (MSLc) mediates upregulation of the single male X chromosome. Here the authors provide evidence that MSL2 also targets autosomal genes required for proper development and that MSL2 binds and similarly regulates mouse orthologues.
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29
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Overexpressing lncRNA LAIR increases grain yield and regulates neighbouring gene cluster expression in rice. Nat Commun 2018; 9:3516. [PMID: 30158538 PMCID: PMC6115402 DOI: 10.1038/s41467-018-05829-7] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 07/26/2018] [Indexed: 12/21/2022] Open
Abstract
Long noncoding RNAs (lncRNAs) are essential regulators of gene expression in eukaryotes. Despite increasing knowledge on the function of lncRNAs, little is known about their effects on crop yield. Here, we identify a lncRNA transcribed from the antisense strand of neighbouring gene LRK (leucine-rich repeat receptor kinase) cluster named LAIR (LRK Antisense Intergenic RNA). LAIR overexpression increases rice grain yield and upregulates the expression of several LRK genes. Additionally, chromatin immunoprecipitation assay results indicate H3K4me3 and H4K16ac are significantly enriched at the activated LRK1 genomic region. LAIR binds histone modification proteins OsMOF and OsWDR5 in rice cells, which are enriched in LRK1 gene region. Moreover, LAIR is demonstrated to bind 5' and 3' untranslated regions of LRK1 gene. Overall, this study reveals the role of lncRNA LAIR in regulating rice grain yield and lncRNAs may be useful targets for crop breeding.
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Zhou QZ, Fang SM, Zhang Q, Yu QY, Zhang Z. Identification and comparison of long non-coding RNAs in the silk gland between domestic and wild silkworms. INSECT SCIENCE 2018; 25:604-616. [PMID: 28111905 DOI: 10.1111/1744-7917.12443] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 12/03/2016] [Accepted: 12/29/2016] [Indexed: 06/06/2023]
Abstract
Under long-term artificial selection, the domestic silkworm (Bombyx mori) has increased its silk yield tremendously in comparison with its wild progenitor, Bombyx mandarina. However, the molecular mechanism of silk yield increase is still unknown. Comparative analysis of long non-coding RNAs (lncRNAs) may provide some insights into understanding this phenotypic variation. In this study, using RNA sequencing technology data of silk gland in domestic and wild silkworms, we identified 599 lncRNAs in the silk gland of the silkworm. Compared with protein-coding genes, the silk gland lncRNA genes tend to have fewer exon numbers, shorter transcript length and lower GC-content. Moreover, we found that three lncRNA genes are significantly and differentially expressed between domestic and wild silkworms. The potential targets of two differentially expressed lncRNAs (DELs) (dw4sg_0040 and dw4sg_0483) and the expression-correlated genes with the two DELs are mainly enriched in the related processes of silk protein translation. This implies that these DELs may affect the phenotypic variation in silk yield between the domestic and wild silkworms through the post-transcriptional regulation of silk protein.
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Affiliation(s)
- Qiu-Zhong Zhou
- Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing, China
| | - Shou-Min Fang
- College of Life Science, China West Normal University, Nanchong, Sichuan, China
| | - Qiang Zhang
- Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing, China
| | - Quan-You Yu
- Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing, China
| | - Ze Zhang
- Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing, China
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31
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Monfort A, Wutz A. Progress in understanding the molecular mechanism of Xist RNA function through genetics. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0368. [PMID: 28947663 DOI: 10.1098/rstb.2016.0368] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2017] [Indexed: 01/06/2023] Open
Abstract
The Xist gene produces a long noncoding RNA that initiates chromosome-wide gene repression on the inactive X chromosome in female mammals. Recent progress has advanced the understanding of Xist function at the molecular level. This review provides an overview of insights from genetic approaches and puts the new data in the context of an emerging mechanistic model as well as the existing literature. Some consideration is given on how independent biochemical studies on X inactivation help to advance on the wider question of chromatin regulation in the mammalian dosage compensation system.This article is part of the themed issue 'X-chromosome inactivation: a tribute to Mary Lyon'.
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Affiliation(s)
- Asun Monfort
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology, ETH Hönggerberg, Otto-Stern-Weg 7, 8049 Zurich, Switzerland
| | - Anton Wutz
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology, ETH Hönggerberg, Otto-Stern-Weg 7, 8049 Zurich, Switzerland
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32
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33
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Samata M, Akhtar A. Dosage Compensation of the X Chromosome: A Complex Epigenetic Assignment Involving Chromatin Regulators and Long Noncoding RNAs. Annu Rev Biochem 2018; 87:323-350. [PMID: 29668306 DOI: 10.1146/annurev-biochem-062917-011816] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
X chromosome regulation represents a prime example of an epigenetic phenomenon where coordinated regulation of a whole chromosome is required. In flies, this is achieved by transcriptional upregulation of X chromosomal genes in males to equalize the gene dosage differences in females. Chromatin-bound proteins and long noncoding RNAs (lncRNAs) constituting a ribonucleoprotein complex known as the male-specific lethal (MSL) complex or the dosage compensation complex mediate this process. MSL complex members decorate the male X chromosome, and their absence leads to male lethality. The male X chromosome is also enriched with histone H4 lysine 16 acetylation (H4K16ac), indicating that the chromatin compaction status of the X chromosome also plays an important role in transcriptional activation. How the X chromosome is specifically targeted and how dosage compensation is mechanistically achieved are central questions for the field. Here, we review recent advances, which reveal a complex interplay among lncRNAs, the chromatin landscape, transcription, and chromosome conformation that fine-tune X chromosome gene expression.
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Affiliation(s)
- Maria Samata
- Department of Chromatin Regulation, Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg im Breisgau, Germany; .,Faculty of Biology, University of Freiburg, 79104 Freiburg im Breisgau, Germany
| | - Asifa Akhtar
- Department of Chromatin Regulation, Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg im Breisgau, Germany;
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34
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Tang W, Seth M, Tu S, Shen EZ, Li Q, Shirayama M, Weng Z, Mello CC. A Sex Chromosome piRNA Promotes Robust Dosage Compensation and Sex Determination in C. elegans. Dev Cell 2018; 44:762-770.e3. [PMID: 29456136 DOI: 10.1016/j.devcel.2018.01.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 01/22/2018] [Accepted: 01/28/2018] [Indexed: 01/25/2023]
Abstract
In metazoans, Piwi-related Argonaute proteins engage piRNAs (Piwi-interacting small RNAs) to defend the genome against invasive nucleic acids, such as transposable elements. Yet many organisms-including worms and humans-express thousands of piRNAs that do not target transposons, suggesting that piRNA function extends beyond genome defense. Here, we show that the X chromosome-derived piRNA 21ux-1 downregulates XOL-1 (XO Lethal), a master regulator of X chromosome dosage compensation and sex determination in Caenorhabditis elegans. Mutations in 21ux-1 and several Piwi-pathway components sensitize hermaphrodites to dosage compensation and sex determination defects. We show that the piRNA pathway also targets xol-1 in C. briggsae, a nematode species related to C. elegans. Our findings reveal physiologically important piRNA-mRNA interactions, raising the possibility that piRNAs function broadly to ensure robust gene expression and germline development.
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Affiliation(s)
- Wen Tang
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Meetu Seth
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Shikui Tu
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - En-Zhi Shen
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Qian Li
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Masaki Shirayama
- RNA Therapeutics Institute, Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Zhiping Weng
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Craig C Mello
- RNA Therapeutics Institute, Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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35
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Lakhotia SC. From Heterochromatin to Long Noncoding RNAs in Drosophila: Expanding the Arena of Gene Function and Regulation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1008:75-118. [PMID: 28815537 DOI: 10.1007/978-981-10-5203-3_3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Recent years have witnessed a remarkable interest in exploring the significance of pervasive noncoding transcripts in diverse eukaryotes. Classical cytogenetic studies using the Drosophila model system unraveled the perplexing attributes and "functions" of the "gene"-poor heterochromatin. Recent molecular studies in the fly model are likewise revealing the very diverse and significant roles played by long noncoding RNAs (lncRNAs) in development, gene regulation, chromatin organization, cell and nuclear architecture, etc. There has been a rapid increase in the number of identified lncRNAs, although a much larger number still remains unknown. The diversity of modes of actions and functions of the limited number of Drosophila lncRNAs, which have been examined, already reflects the profound roles of such RNAs in generating and sustaining the biological complexities of eukaryotes. Several of the known Drosophila lncRNAs originate as independent sense or antisense transcripts from promoter or intergenic, intronic, or 5'/3'-UTR regions, while many of them are independent genes that produce only lncRNAs or coding as well as noncoding RNAs. The different lncRNAs affect chromatin organization (local or large-scale pan-chromosomal), transcription, RNA processing/stability, or translation either directly through interaction with their target DNA sequences or indirectly by acting as intermediary molecules for specific regulatory proteins or may act as decoys/sinks, or storage sites for specific proteins or groups of proteins, or may provide a structural framework for the assembly of substructures in nucleus/cytoplasm. It is interesting that many of the "functions" alluded to heterochromatin in earlier cytogenetic studies appear to find correlates with the known subtle as well as far-reaching actions of the different small and long noncoding RNAs. Further studies exploiting the very rich and powerful genetic and molecular resources available for the Drosophila model are expected to unravel the mystery underlying the long reach of ncRNAs.
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Affiliation(s)
- Subhash C Lakhotia
- Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, 221005, India.
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36
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Cheetham SW, Brand AH. RNA-DamID reveals cell-type-specific binding of roX RNAs at chromatin-entry sites. Nat Struct Mol Biol 2017; 25:109-114. [PMID: 29323275 PMCID: PMC5813796 DOI: 10.1038/s41594-017-0006-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 11/09/2017] [Indexed: 02/08/2023]
Abstract
Thousands of long noncoding RNAs (lncRNAs) have been identified in eukaryotic genomes, many of which are expressed in spatially and temporally restricted patterns. Nonetheless, the roles of the majority of these transcripts are still unknown. One of the mechanisms by which lncRNAs function is through the modulation of chromatin state. To assess the functions of lncRNAs we developed RNA-DamID, a novel approach that detects lncRNA-genome interactions in a cell-type specific manner in vivo with high sensitivity and accuracy. Identifying the cell-type-specific genome occupancy of lncRNAs is key to understanding their mechanisms of action in development and disease. We used RNA-DamID to investigate targeting of the lncRNAs in the Drosophila dosage compensation complex (DCC) and show that initial targeting is cell-type-specific.
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Affiliation(s)
- Seth W Cheetham
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.,Mater Research Institute, University of Queensland, Wooloongabba, Queensland, Australia
| | - Andrea H Brand
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
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37
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Li H, Horns F, Wu B, Xie Q, Li J, Li T, Luginbuhl DJ, Quake SR, Luo L. Classifying Drosophila Olfactory Projection Neuron Subtypes by Single-Cell RNA Sequencing. Cell 2017; 171:1206-1220.e22. [PMID: 29149607 DOI: 10.1016/j.cell.2017.10.019] [Citation(s) in RCA: 160] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Revised: 08/05/2017] [Accepted: 10/12/2017] [Indexed: 11/19/2022]
Abstract
The definition of neuronal type and how it relates to the transcriptome are open questions. Drosophila olfactory projection neurons (PNs) are among the best-characterized neuronal types: different PN classes target dendrites to distinct olfactory glomeruli, while PNs of the same class exhibit indistinguishable anatomical and physiological properties. Using single-cell RNA sequencing, we comprehensively characterized the transcriptomes of most PN classes and unequivocally mapped transcriptomes to specific olfactory function for six classes. Transcriptomes of closely related PN classes exhibit the largest differences during circuit assembly but become indistinguishable in adults, suggesting that neuronal subtype diversity peaks during development. Transcription factors and cell-surface molecules are the most differentially expressed genes between classes and are highly informative in encoding cell identity, enabling us to identify a new lineage-specific transcription factor that instructs PN dendrite targeting. These findings establish that neuronal transcriptomic identity corresponds with anatomical and physiological identity defined by connectivity and function.
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Affiliation(s)
- Hongjie Li
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Felix Horns
- Biophysics Graduate Program, Stanford University, Stanford, CA 94305, USA
| | - Bing Wu
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Qijing Xie
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Neurosciences Graduate Program, Stanford University, Stanford, CA 94305, USA
| | - Jiefu Li
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Tongchao Li
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - David J Luginbuhl
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Stephen R Quake
- Departments of Bioengineering and Applied Physics, Stanford University, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, Stanford, CA 94305, USA.
| | - Liqun Luo
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
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38
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Lakhotia SC. Non-coding RNAs demystify constitutive heterochromatin as essential modulator of epigenotype. THE NUCLEUS 2017. [DOI: 10.1007/s13237-017-0221-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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39
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Long Y, Wang X, Youmans DT, Cech TR. How do lncRNAs regulate transcription? SCIENCE ADVANCES 2017; 3:eaao2110. [PMID: 28959731 PMCID: PMC5617379 DOI: 10.1126/sciadv.aao2110] [Citation(s) in RCA: 466] [Impact Index Per Article: 66.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 09/12/2017] [Indexed: 05/11/2023]
Abstract
It has recently become apparent that RNA, itself the product of transcription, is a major regulator of the transcriptional process. In particular, long noncoding RNAs (lncRNAs), which are so numerous in eukaryotes, function in many cases as transcriptional regulators. These RNAs function through binding to histone-modifying complexes, to DNA binding proteins (including transcription factors), and even to RNA polymerase II. In other cases, it is the act of lncRNA transcription rather than the lncRNA product that appears to be regulatory. We review recent progress in elucidating the molecular mechanisms by which lncRNAs modulate gene expression and future opportunities in this research field.
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Affiliation(s)
- Yicheng Long
- Department of Chemistry and Biochemistry, University of Colorado BioFrontiers Institute, and Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80309, USA
| | - Xueyin Wang
- Department of Chemistry and Biochemistry, University of Colorado BioFrontiers Institute, and Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80309, USA
| | - Daniel T. Youmans
- Department of Chemistry and Biochemistry, University of Colorado BioFrontiers Institute, and Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80309, USA
- Anschutz Medical Campus, University of Colorado Denver, Aurora, CO 80045, USA
| | - Thomas R. Cech
- Department of Chemistry and Biochemistry, University of Colorado BioFrontiers Institute, and Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80309, USA
- Corresponding author.
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40
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Abstract
Several recent studies in a number of model systems including zebrafish, Arabidopsis, and mouse have revealed phenotypic differences between knockouts (i.e., mutants) and knockdowns (e.g., antisense-treated animals). These differences have been attributed to a number of reasons including off-target effects of the antisense reagents. An alternative explanation was recently proposed based on a zebrafish study reporting that genetic compensation was observed in egfl7 mutant but not knockdown animals. Dosage compensation was first reported in Drosophila in 1932, and genetic compensation in response to a gene knockout was first reported in yeast in 1969. Since then, genetic compensation has been documented many times in a number of model organisms; however, our understanding of the underlying molecular mechanisms remains limited. In this review, we revisit studies reporting genetic compensation in higher eukaryotes and outline possible molecular mechanisms, which may include both transcriptional and posttranscriptional processes.
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Affiliation(s)
- Mohamed A. El-Brolosy
- Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Didier Y. R. Stainier
- Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
- * E-mail:
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41
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Dosage Compensation in Drosophila-a Model for the Coordinate Regulation of Transcription. Genetics 2017; 204:435-450. [PMID: 27729494 DOI: 10.1534/genetics.115.185108] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 07/25/2016] [Indexed: 12/20/2022] Open
Abstract
The sex chromosomes have special significance in the history of genetics. The chromosomal basis of inheritance was firmly established when Calvin Bridges demonstrated that exceptions to Mendel's laws of segregation were accompanied at the cytological level by exceptional sex chromosome segregation. The morphological differences between X and Y exploited in Bridges' experiments arose as a consequence of the evolution of the sex chromosomes. Originally a homologous chromosome pair, the degeneration of the Y chromosome has been accompanied by a requirement for increased expression of the single X chromosome in males. Drosophila has been a model for the study of this dosage compensation and has brought key strengths, including classical genetics, the exceptional cytology of polytene chromosomes, and more recently, comprehensive genomics. The impact of these studies goes beyond sex chromosome regulation, providing valuable insights into mechanisms for the establishment and maintenance of chromatin domains, and for the coordinate regulation of transcription.
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42
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Abstract
Nucleus is the residence and place of work for a plethora of long noncoding RNAs. Here, we provide a summary of the functions and functional mechanisms of several relatively well studied examples of nuclear long noncoding RNAs (lncRNAs) in the nucleus, such as Xist, NEAT1, MALAT1 and TERRA. The recently identified novel EIciRNA is also highlighted. These nuclear lncRNAs play a variety of roles with diverse molecular mechanisms in animal cells. We also discuss insights and concerns about current and future studies of nuclear lnc RNAs.
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Affiliation(s)
- Bin Yu
- a The CAS Key Laboratory of Innate Immunity and Chronic Disease , CAS Center for Excellence in Molecular Cell Science , School of Life Sciences , University of Science and Technology of China , Hefei , Anhui Province , China
| | - Ge Shan
- a The CAS Key Laboratory of Innate Immunity and Chronic Disease , CAS Center for Excellence in Molecular Cell Science , School of Life Sciences , University of Science and Technology of China , Hefei , Anhui Province , China
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43
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Urban JA, Doherty CA, Jordan WT, Bliss JE, Feng J, Soruco MM, Rieder LE, Tsiarli MA, Larschan EN. The essential Drosophila CLAMP protein differentially regulates non-coding roX RNAs in male and females. Chromosome Res 2016; 25:101-113. [PMID: 27995349 DOI: 10.1007/s10577-016-9541-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 12/06/2016] [Accepted: 12/06/2016] [Indexed: 02/05/2023]
Abstract
Heterogametic species require chromosome-wide gene regulation to compensate for differences in sex chromosome gene dosage. In Drosophila melanogaster, transcriptional output from the single male X-chromosome is equalized to that of XX females by recruitment of the male-specific lethal (MSL) complex, which increases transcript levels of active genes 2-fold. The MSL complex contains several protein components and two non-coding RNA on the X ( roX) RNAs that are transcriptionally activated by the MSL complex. We previously discovered that targeting of the MSL complex to the X-chromosome is dependent on the chromatin-linked adapter for MSL proteins (CLAMP) zinc finger protein. To better understand CLAMP function, we used the CRISPR/Cas9 genome editing system to generate a frameshift mutation in the clamp gene that eliminates expression of the CLAMP protein. We found that clamp null females die at the third instar larval stage, while almost all clamp null males die at earlier developmental stages. Moreover, we found that in clamp null females roX gene expression is activated, whereas in clamp null males roX gene expression is reduced. Therefore, CLAMP regulates roX abundance in a sex-specific manner. Our results provide new insights into sex-specific gene regulation by an essential transcription factor.
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Affiliation(s)
- Jennifer A Urban
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02912, USA
| | - Caroline A Doherty
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02912, USA.,Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA
| | - William T Jordan
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02912, USA
| | - Jacob E Bliss
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02912, USA
| | - Jessica Feng
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02912, USA.,University of Massachusetts Medical School, Worcester, MA, 01655, USA
| | - Marcela M Soruco
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02912, USA.,LGC Biosearch Technologies, Petaluma, CA, 94954, USA
| | - Leila E Rieder
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02912, USA
| | - Maria A Tsiarli
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02912, USA
| | - Erica N Larschan
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02912, USA.
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44
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Abstract
How sex is determined has been one of the most intriguing puzzles in biology since antiquity. Although a fundamental process in most metazoans, there seems to be myriad of ways in which sex can be determined - from genetic to environmental sex determination. This variation is limited mainly to upstream triggers with the core of sex determination pathway being conserved. Zebrafish has gained prominence as a vertebrate model system to study development and disease. However, very little is known about its primary sex determination mechanism. Here we review our current understanding of the sex determination in zebrafish. Zebrafish lack identifiable heteromorphic sex chromosomes and sex is determined by multiple genes, with some influence from the environment. Recently, chromosome 4 has been identified as sex chromosome along with few sex-linked loci on chromosomes 5 and 16. The identities of candidate sex-linked genes, however, have remained elusive. Sex in zebrafish is also influenced by the number of meiotic oocytes in the juvenile ovary, which appear to instruct retention of the ovarian fate. The mechanism and identity of this instructive signal remain unknown. We hypothesize that sex in zebrafish is a culmination of combinatorial effects of the genome, germ cells and the environment with inputs from epigenetic factors translating the biological meaning of this interaction.
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Affiliation(s)
- A Nagabhushana
- Centre for Cellular and Molecular Biology, Council of Scientific and industrial Research, Uppal Road, Hyderabad 500007, India
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45
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Nainar S, Feng C, Spitale RC. Chemical Tools for Dissecting the Role of lncRNAs in Epigenetic Regulation. ACS Chem Biol 2016; 11:2091-100. [PMID: 27267401 PMCID: PMC5068361 DOI: 10.1021/acschembio.6b00366] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Proper control and maintenance of gene expression is critical for cellular identity and maintenance. Transcription of RNA from the genome is intimately controlled by post-translational chemical modification of histone tails and DNA. Recent studies have demonstrated that chromatin-remodeling complexes seek out their target genomic loci through the help of noncoding RNA molecules. Within this Review, we will outline how the use of biochemical techniques has shed light on the mechanisms employed by RNA to guide these complexes and therefore control gene expression.
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Affiliation(s)
- Sarah Nainar
- Department of Pharmaceutical Sciences, University of California, Irvine. Irvine, California 92697, United States
| | - Chao Feng
- Department of Pharmaceutical Sciences, University of California, Irvine. Irvine, California 92697, United States
| | - Robert C. Spitale
- Department of Pharmaceutical Sciences, University of California, Irvine. Irvine, California 92697, United States
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46
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Bhadra U, Gandhi SG, Palaparthi R, Balyan MK, Pal-Bhadra M. Drosophila maleless gene counteracts X global aneuploid effects in males. FEBS J 2016; 283:3457-70. [PMID: 27456781 DOI: 10.1111/febs.13818] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 06/27/2016] [Accepted: 07/22/2016] [Indexed: 11/30/2022]
Abstract
UNLABELLED The loss of the entire X chromosome in Drosophila males generates a genome-wide aneuploid effect. We have employed a systems biology approach (microarray) to investigate the global aneuploid effect of the maleless (mle) mutation that disrupts the binding of male specific lethal (MSL) proteins that function in dosage compensation. A large number of the genes (144) that encode a broad spectrum of cellular transport proteins and transcription factors are located mainly in the autosomes of Drosophila melanogaster. We found several such targets to be sensitive to the aneuploid effect and conserved with the X chromosome in primitive Drosophila species and Anopheles gambiae. During evolution, they shifted gradually from their X-chromosomal positions to the autosomes in the species D. melanogaster, suggesting that the counteraction of trans-acting regulatory modifiers and their targets in two separate chromosomes is evolutionarily advantageous. These findings suggest a remarkable and previously unexpected level of complexity favoring natural compensation for the aneuploid effect. We propose that the MSL complex functions in dosage compensation in two separate steps. Initially, X-linked genes including X-linked trans-acting modifiers are hyperactivated in dosage compensated males. Later, these compensated modifiers eventually mitigate inverse aneuploid effects for the equality in expression of their autosomal targets in males and females. DATABASE Microarray data are available at the Gene Expression Omnibus (GEO) web deposit of National Centre for Biotechnology Information (NCBI) with the accession number GSE78227.
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Affiliation(s)
- Utpal Bhadra
- Functional Genomics and Gene Silencing Group, Centre for Cellular and Molecular Biology, Hyderabad, India.
| | - Sumit G Gandhi
- Functional Genomics and Gene Silencing Group, Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Ramesh Palaparthi
- Functional Genomics and Gene Silencing Group, Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Manoj K Balyan
- Functional Genomics and Gene Silencing Group, Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Manika Pal-Bhadra
- Centre for Chemical Biology, Indian Institute of Chemical Technology, Hyderabad, India.
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47
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Quinn JJ, Zhang QC, Georgiev P, Ilik IA, Akhtar A, Chang HY. Rapid evolutionary turnover underlies conserved lncRNA-genome interactions. Genes Dev 2016; 30:191-207. [PMID: 26773003 PMCID: PMC4719309 DOI: 10.1101/gad.272187.115] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Many long noncoding RNAs (lncRNAs) can regulate chromatin states, but the evolutionary origin and dynamics driving lncRNA-genome interactions are unclear. We adapted an integrative strategy that identifies lncRNA orthologs in different species despite limited sequence similarity, which is applicable to mammalian and insect lncRNAs. Analysis of the roX lncRNAs, which are essential for dosage compensation of the single X chromosome in Drosophila males, revealed 47 new roX orthologs in diverse Drosophilid species across ∼40 million years of evolution. Genetic rescue by roX orthologs and engineered synthetic lncRNAs showed that altering the number of focal, repetitive RNA structures determines roX ortholog function. Genomic occupancy maps of roX RNAs in four species revealed conserved targeting of X chromosome neighborhoods but rapid turnover of individual binding sites. Many new roX-binding sites evolved from DNA encoding a pre-existing RNA splicing signal, effectively linking dosage compensation to transcribed genes. Thus, dynamic change in lncRNAs and their genomic targets underlies conserved and essential lncRNA-genome interactions.
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Affiliation(s)
- Jeffrey J Quinn
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, California 94305, USA; Department of Bioengineering, Stanford University School of Medicine and School of Engineering, Stanford, California 94305, USA
| | - Qiangfeng C Zhang
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Plamen Georgiev
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg im Breisgau, Germany
| | - Ibrahim A Ilik
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg im Breisgau, Germany
| | - Asifa Akhtar
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg im Breisgau, Germany
| | - Howard Y Chang
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, California 94305, USA
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48
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Birchler JA. Parallel Universes for Models of X Chromosome Dosage Compensation in Drosophila: A Review. Cytogenet Genome Res 2016; 148:52-67. [PMID: 27166165 DOI: 10.1159/000445924] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2016] [Indexed: 11/19/2022] Open
Abstract
Dosage compensation in Drosophila involves an approximately 2-fold increase in expression of the single X chromosome in males compared to the per gene expression in females with 2 X chromosomes. Two models have been considered for an explanation. One proposes that the male-specific lethal (MSL) complex that is associated with the male X chromosome brings histone modifiers to the sex chromosome to increase its expression. The other proposes that the inverse effect which results from genomic imbalance would tend to upregulate the genome approximately 2-fold, but the MSL complex sequesters histone modifiers from the autosomes to the X to mute this autosomal male-biased expression. On the X, the MSL complex must override the high level of resulting histone modifications to prevent overcompensation of the X chromosome. Each model is evaluated in terms of fitting classical genetic and recent molecular data. Potential paths toward resolving the models are suggested.
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Affiliation(s)
- James A Birchler
- Division of Biological Sciences, University of Missouri, Columbia, Mo., USA
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49
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Cheng B, Kuppanda N, Aldrich JC, Akbari OS, Ferree PM. Male-Killing Spiroplasma Alters Behavior of the Dosage Compensation Complex during Drosophila melanogaster Embryogenesis. Curr Biol 2016; 26:1339-45. [PMID: 27161498 DOI: 10.1016/j.cub.2016.03.050] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 03/16/2016] [Accepted: 03/21/2016] [Indexed: 01/11/2023]
Abstract
Numerous arthropods harbor maternally transmitted bacteria that induce the preferential death of males [1-7]. This sex-specific lethality benefits the bacteria because males are "dead ends" regarding bacterial transmission, and their absence may result in additional resources for their viable female siblings who can thereby more successfully transmit the bacteria [5]. Although these symbionts disrupt a range of developmental processes [8-10], the underlying cellular mechanisms are largely unknown. It was previously shown that mutations in genes of the dosage compensation pathway of Drosophila melanogaster suppressed male killing caused by the bacterium, Spiroplasma [10]. This result suggested that dosage compensation is a target of Spiroplasma. However, it remains unclear how this pathway is affected, and whether the underlying interactions require the male-specific cellular environment. Here, we investigated the cellular basis of male embryonic lethality in D. melanogaster induced by Spiroplasma. We found that the dosage compensation complex (DCC), which acetylates X chromatin in males [11], becomes mis-localized to ectopic regions of the nucleus immediately prior to the killing phase. This effect was accompanied by inappropriate histone acetylation and genome-wide mis-regulation of gene expression. Artificially induced formation of the DCC in infected females, through transgenic expression of the DCC-specific gene msl-2, resulted in mis-localization of this complex to non-X regions and early Spiroplasma-induced death, mirroring the killing effects in males. These findings strongly suggest that Spiroplasma initiates male killing by targeting the dosage compensation machinery directly and independently of other cellular features characteristic of the male sex.
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Affiliation(s)
- Becky Cheng
- W.M. Keck Science Department, Claremont McKenna, Pitzer and Scripps Colleges, 925 N. Mills Avenue, Claremont, CA 91711, USA
| | - Nitin Kuppanda
- W.M. Keck Science Department, Claremont McKenna, Pitzer and Scripps Colleges, 925 N. Mills Avenue, Claremont, CA 91711, USA
| | - John C Aldrich
- W.M. Keck Science Department, Claremont McKenna, Pitzer and Scripps Colleges, 925 N. Mills Avenue, Claremont, CA 91711, USA
| | - Omar S Akbari
- Department of Entomology and Riverside Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA 92521, USA.
| | - Patrick M Ferree
- W.M. Keck Science Department, Claremont McKenna, Pitzer and Scripps Colleges, 925 N. Mills Avenue, Claremont, CA 91711, USA.
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50
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Rutenberg-Schoenberg M, Sexton AN, Simon MD. The Properties of Long Noncoding RNAs That Regulate Chromatin. Annu Rev Genomics Hum Genet 2016; 17:69-94. [PMID: 27147088 DOI: 10.1146/annurev-genom-090314-024939] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Beyond coding for proteins, RNA molecules have well-established functions in the posttranscriptional regulation of gene expression. Less clear are the upstream roles of RNA in regulating transcription and chromatin-based processes in the nucleus. RNA is transcribed in the nucleus, so it is logical that RNA could play diverse and broad roles that would impact human physiology. Indeed, this idea is supported by well-established examples of noncoding RNAs that affect chromatin structure and function. There has been dramatic growth in studies focused on the nuclear roles of long noncoding RNAs (lncRNAs). Although little is known about the biochemical mechanisms of these lncRNAs, there is a developing consensus regarding the challenges of defining lncRNA function and mechanism. In this review, we examine the definition, discovery, functions, and mechanisms of lncRNAs. We emphasize areas where challenges remain and where consensus among laboratories has underscored the exciting ways in which human lncRNAs may affect chromatin biology.
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Affiliation(s)
- Michael Rutenberg-Schoenberg
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511; , , .,Chemical Biology Institute, Yale University, West Haven, Connecticut 06516
| | - Alec N Sexton
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511; , , .,Chemical Biology Institute, Yale University, West Haven, Connecticut 06516
| | - Matthew D Simon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511; , , .,Chemical Biology Institute, Yale University, West Haven, Connecticut 06516
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