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Asad S, Mehdi AM, Pujhari S, Rückert C, Ebel GD, Rasgon JL. Identification of MicroRNAs in the West Nile Virus Vector Culex tarsalis (Diptera: Culicidae). JOURNAL OF MEDICAL ENTOMOLOGY 2023; 60:182-293. [PMID: 36477983 PMCID: PMC10216877 DOI: 10.1093/jme/tjac182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Indexed: 05/28/2023]
Abstract
MicroRNAs (miRNAs) are a group of small noncoding RNAs that regulate gene expression during important biological processes including development and pathogen defense in most living organisms. Presently, no miRNAs have been identified in the mosquito Culex tarsalis (Diptera: Culicidae), one of the most important vectors of West Nile virus (WNV) in North America. We used small RNA sequencing data and in vitro and in vivo experiments to identify and validate a repertoire of miRNAs in Cx. tarsalis mosquitoes. Using bioinformatic approaches we analyzed small RNA sequences from the Cx. tarsalis CT embryonic cell line to discover orthologs for 86 miRNAs. Consistent with other mosquitoes such as Aedes albopictus and Culex quinquefasciatus, miR-184 was found to be the most abundant miRNA in Cx. tarsalis. We also identified 20 novel miRNAs from the recently sequenced Cx. tarsalis genome, for a total of 106 miRNAs identified in this study. The presence of selected miRNAs was biologically validated in both the CT cell line and in adult Cx. tarsalis mosquitoes using RT-qPCR and sequencing. These results will open new avenues of research into the role of miRNAs in Cx. tarsalis biology, including development, metabolism, immunity, and pathogen infection.
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Affiliation(s)
- Sultan Asad
- Department of Entomology, The Center for Infectious Disease Dynamics, and the Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Ahmed M Mehdi
- The University of Queensland, Brisbane, Australia Diamantina Institute, Faculty of Medicine, The University of Queensland, Translational Research Institute, Brisbane, QLD, Australia
| | - Sujit Pujhari
- Department of Entomology, The Center for Infectious Disease Dynamics, and the Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
- Department of Pharmacology Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Claudia Rückert
- Department of Biochemistry and Molecular Biology, University of Nevada Reno, Reno, NV, 89557, USA
- Department of Microbiology, Immunology and Pathology, Center for Vector-borne Infectious Diseases, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, 80523, USAand
| | - Gregory D Ebel
- Department of Microbiology, Immunology and Pathology, Center for Vector-borne Infectious Diseases, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, 80523, USAand
| | - Jason L Rasgon
- Department of Entomology, The Center for Infectious Disease Dynamics, and the Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
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Main BJ, Marcantonio M, Johnston JS, Rasgon JL, Brown CT, Barker CM. Whole-genome assembly of Culex tarsalis. G3 (BETHESDA, MD.) 2021; 11:jkaa063. [PMID: 33585869 PMCID: PMC8022977 DOI: 10.1093/g3journal/jkaa063] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/09/2020] [Indexed: 12/12/2022]
Abstract
The mosquito, Culex tarsalis, is a key vector in the western United States due to its role in transmission of zoonotic arboviruses that affect human health. Extensive research has been conducted on Cx. tarsalis ecology, feeding behavior, vector competence, autogeny, diapause, genetics, and insecticide resistance. Population genetic analyses in the western U.S. have identified at least three genetic clusters that are geographically distinct. However, in-depth genetic studies have been hindered by the lack of a reference genome. In this study, we present the first whole-genome assembly of this mosquito species (CtarK1) based on PacBio HiFi reads from high-molecular-weight DNA extracted from a single male. The CtarK1 assembly is 790 Mb with an N50 of 58 kb, which is 27% larger than Culex quinquefasciatus (578 Mb). This difference appears to be mostly composed of transposable elements. To annotate CtarK1, we used a previously assembled Cx. tarsalis transcriptome and approximately 17,456 protein genes from Cx. quinquefasciatus (N = 17,456). Genome completeness was assessed using the Benchmarking Universal Single-Copy Orthologs (BUSCO) tool, which identified 84.8% of the 2799 Dipteran BUSCO genes. Using a Bayesian phylogeny based on mitochondrial genomes, we place Cx. tarsalis in the context of other mosquito species and estimate the divergence between Cx. tarsalis and Cx. quinquefasciatus to be between 15.8 and 22.2 million years ago (MYA). Important next steps from this work include characterizing the genetic basis of diapause and sex determination in Culex mosquitoes.
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Affiliation(s)
- Bradley J Main
- Department of Pathology, Microbiology and Immunology, University of California, Davis, CA 95616, USA
| | - Matteo Marcantonio
- Department of Pathology, Microbiology and Immunology, University of California, Davis, CA 95616, USA
| | - J Spencer Johnston
- Department of Entomology, Texas A&M University, College Station, TX 77843, USA
| | - Jason L Rasgon
- Department of Entomology, The Center for Infectious Disease Dynamics, and the Huck Institutes of the Life Sciences, University Park, PA 16802, USA
| | - C Titus Brown
- Department of Population Health and Reproduction, University of California, Davis, CA 95616, USA
| | - Christopher M Barker
- Department of Pathology, Microbiology and Immunology, University of California, Davis, CA 95616, USA
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Zou F, Chen C, Zhong D, Shen B, Zhang D, Guo Q, Wang W, Yu J, Lv Y, Lei Z, Ma K, Ma L, Zhu C, Yan G. Identification of QTLs Conferring Resistance to Deltamethrin in Culex pipiens pallens. PLoS One 2015; 10:e0140923. [PMID: 26484540 PMCID: PMC4617896 DOI: 10.1371/journal.pone.0140923] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 10/01/2015] [Indexed: 11/18/2022] Open
Abstract
Culex pipiens pallens is the most abundant Culex mosquito species in northern China and is an important vector of bancroftian filariasis and West Nile virus. Deltamethrin is an insecticide that is widely used for mosquito control, however resistance to this and other insecticides has become a major challenge in the control of vector-borne diseases that appear to be inherited quantitatively. Furthermore, the genetic basis of insecticide resistance remains poorly understood. In this study, quantitative trait loci (QTL) mapping of resistance to deltamethrin was conducted in F2 intercross segregation populations using bulked segregation analysis (BSA) and amplified fragment length polymorphism markers (AFLP) in Culex pipiens pallens. A genetic linkage map covering 381 cM was constructed and a total of seven QTL responsible for resistance to deltamethrin were detected by composite interval mapping (CIM), which explained 95% of the phenotypic variance. The major QTL in linkage group 2 accounted for 62% of the variance and is worthy of further study. 12 AFLP markers in the map were cloned and the genomic locations of these marker sequences were determined by applying the Basic Local Alignment Search Tool (BLAST) tool to the genome sequence of the closely related Culex quinquefasciatus. Our results suggest that resistance to deltamethrin is a quantitative trait under the control of a major QTL in Culex pipiens pallens. Cloning of related AFLP markers confirm the potential utility for anchoring the genetic map to the physical map. The results provide insight into the genetic architecture of the trait.
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Affiliation(s)
- Feifei Zou
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Chen Chen
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Daibin Zhong
- Program in Public Health, University of California Irvine, Irvine, California, United States of America
| | - Bo Shen
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Donghui Zhang
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Qin Guo
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Weijie Wang
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Jing Yu
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Yuan Lv
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Zhentao Lei
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Kai Ma
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Lei Ma
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, PR China
| | - Changliang Zhu
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, PR China
- * E-mail:
| | - Guiyun Yan
- Program in Public Health, University of California Irvine, Irvine, California, United States of America
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Hall AB, Timoshevskiy VA, Sharakhova MV, Jiang X, Basu S, Anderson MAE, Hu W, Sharakhov IV, Adelman ZN, Tu Z. Insights into the preservation of the homomorphic sex-determining chromosome of Aedes aegypti from the discovery of a male-biased gene tightly linked to the M-locus. Genome Biol Evol 2014; 6:179-91. [PMID: 24398378 PMCID: PMC3914700 DOI: 10.1093/gbe/evu002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The preservation of a homomorphic sex-determining chromosome in some organisms without transformation into a heteromorphic sex chromosome is a long-standing enigma in evolutionary biology. A dominant sex-determining locus (or M-locus) in an undifferentiated homomorphic chromosome confers the male phenotype in the yellow fever mosquito Aedes aegypti. Genetic evidence suggests that the M-locus is in a nonrecombining region. However, the molecular nature of the M-locus has not been characterized. Using a recently developed approach based on Illumina sequencing of male and female genomic DNA, we identified a novel gene, myo-sex, that is present almost exclusively in the male genome but can sporadically be found in the female genome due to recombination. For simplicity, we define sequences that are primarily found in the male genome as male-biased. Fluorescence in situ hybridization (FISH) on A. aegypti chromosomes demonstrated that the myo-sex probe localized to region 1q21, the established location of the M-locus. Myo-sex is a duplicated myosin heavy chain gene that is highly expressed in the pupa and adult male. Myo-sex shares 83% nucleotide identity and 97% amino acid identity with its closest autosomal paralog, consistent with ancient duplication followed by strong purifying selection. Compared with males, myo-sex is expressed at very low levels in the females that acquired it, indicating that myo-sex may be sexually antagonistic. This study establishes a framework to discover male-biased sequences within a homomorphic sex-determining chromosome and offers new insights into the evolutionary forces that have impeded the expansion of the nonrecombining M-locus in A. aegypti.
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Otto SP, Pannell JR, Peichel CL, Ashman TL, Charlesworth D, Chippindale AK, Delph LF, Guerrero RF, Scarpino SV, McAllister BF. About PAR: the distinct evolutionary dynamics of the pseudoautosomal region. Trends Genet 2012; 27:358-67. [PMID: 21962971 DOI: 10.1016/j.tig.2011.05.001] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 05/03/2011] [Accepted: 05/04/2011] [Indexed: 01/05/2023]
Abstract
Sex chromosomes differ from other chromosomes in the striking divergence they often show in size, structure, and gene content. Not only do they possess genes controlling sex determination that are restricted to either the X or Y (or Z or W) chromosomes, but in many taxa they also include recombining regions. In these 'pseudoautosomal regions' (PARs), sequence homology is maintained by meiotic pairing and exchange in the heterogametic sex. PARs are unique genomic regions, exhibiting some features of autosomes, but they are also influenced by their partial sex linkage. Here we review the distribution and structure of PARs among animals and plants, the theoretical predictions concerning their evolutionary dynamics, the reasons for their persistence, and the diversity and content of genes that reside within them. It is now clear that the evolution of the PAR differs in important ways from that of genes in either the non-recombining regions of sex chromosomes or the autosomes.
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Affiliation(s)
- Sarah P Otto
- Department of Zoology, 6270 University Boulevard, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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Sutherland IW, Mori A, Montgomery J, Fleming KL, Anderson JM, Valenzuela JG, Severson DW, Black WC. A linkage map of the Asian tiger mosquito (Aedes albopictus) based on cDNA markers. J Hered 2010; 102:102-12. [PMID: 21148282 DOI: 10.1093/jhered/esq105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The Asian tiger mosquito, Aedes (Stegomyia) albopictus (Skuse), is an important vector of a number of arboviruses, and populations exhibit extreme variation in adaptive traits such as egg diapause, cold hardiness, and autogeny (ability to mature a batch of eggs without blood feeding). The genetic basis of some of these traits has been established, but lack of a high-resolution linkage map has prevented in-depth genetic analyses of the genes underlying these complex traits. We report here on the breeding of 4 F(1) intercross mapping families and the use of these to locate 35 cDNA markers to the A. albopictus linkage map. The present study increases the number of markers on the A. albopictus cDNA linkage map from 38 to 73 and the density of markers from 1 marker/5.7 cM to 1 marker/2.9 cM and adds 9, 16, and 10 markers to the 3 linkage groups, respectively. The overall lengths of the 3 linkage groups are 64.5, 76.5, and 71.6 cM, respectively, for a combined length of 212.6 cM. Despite conservation in the order of most genes among the 4 families and a previous mapping family, we found substantial heterogeneity in the amount of recombination among markers. This was most marked in linkage group I, which varied between 16.7 and 69.3 cM. A map integrating the results from these 4 families with an earlier cDNA linkage map is presented.
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Affiliation(s)
- Ian W Sutherland
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
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Charlesworth D, Mank JE. The birds and the bees and the flowers and the trees: lessons from genetic mapping of sex determination in plants and animals. Genetics 2010; 186:9-31. [PMID: 20855574 PMCID: PMC2940314 DOI: 10.1534/genetics.110.117697] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The ability to identify genetic markers in nonmodel systems has allowed geneticists to construct linkage maps for a diversity of species, and the sex-determining locus is often among the first to be mapped. Sex determination is an important area of study in developmental and evolutionary biology, as well as ecology. Its importance for organisms might suggest that sex determination is highly conserved. However, genetic studies have shown that sex determination mechanisms, and the genes involved, are surprisingly labile. We review studies using genetic mapping and phylogenetic inferences, which can help reveal evolutionary pattern within this lability and potentially identify the changes that have occurred among different sex determination systems. We define some of the terminology, particularly where confusion arises in writing about such a diverse range of organisms, and highlight some major differences between plants and animals, and some important similarities. We stress the importance of studying taxa suitable for testing hypotheses, and the need for phylogenetic studies directed to taxa where the patterns of changes can be most reliably inferred, if the ultimate goal of testing hypotheses regarding the selective forces that have led to changes in such an essential trait is to become feasible.
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Affiliation(s)
- Deborah Charlesworth
- Department of Zoology, Edward Grey Institute, University of Oxford, Oxford OX1 3PS, United Kingdom.
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