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Wang B, Mao Z, Chen Y, Ying J, Wang H, Sun Z, Li J, Zhang C, Zhuo J. Identification and Functional Analysis of the fruitless Gene in a Hemimetabolous Insect, Nilaparvata lugens. INSECTS 2024; 15:262. [PMID: 38667392 PMCID: PMC11050625 DOI: 10.3390/insects15040262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/01/2024] [Accepted: 04/10/2024] [Indexed: 04/28/2024]
Abstract
The fruitless (fru) gene functions as a crucial "tuner" in male insect courtship behavior through distinct expression patterns. In Nilaparvata lugens, our previous research showed doublesex (dsx) influencing male courtship songs, causing mating failures with virgin females. However, the impact of fru on N. lugens mating remains unexplored. In this study, the fru homolog (Nlfru) in N. lugens yielded four spliceosomes: Nlfru-374-a/b, Nlfru-377, and Nlfru-433, encoding proteins of 374aa, 377aa, and 433aa, respectively. Notably, only Nlfru-374b exhibited male bias, while the others were non-sex-specific. All NlFRU proteins featured the BTB conserved domain, with NlFRU-374 and NlFRU-377 possessing the ZnF domain with different sequences. RNAi-mediated Nlfru or its isoforms' knockdown in nymph stages blocked wing-flapping behavior in mating males, while embryonic knockdown via maternal RNAi resulted in over 80% of males losing wing-flapping ability, and female receptivity was reduced. Nlfru expression was Nldsx-regulated, and yet courtship signals and mating success were unaffected. Remarkably, RNAi-mediated Nlfru knockdown up-regulated the expression of flightin in macropterous males, which regulated muscle stiffness and delayed force response, suggesting Nlfru's involvement in muscle development regulation. Collectively, our results indicate that Nlfru functions in N. lugens exhibit a combination of conservation and species specificity, contributing insights into fru evolution, particularly in Hemiptera species.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Jichong Zhuo
- State Key Laboratory for ManagingBiotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Biotechnology in Plant Protection of MARA and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China; (B.W.); (Z.M.); (Y.C.); (J.Y.); (H.W.); (Z.S.); (J.L.); (C.Z.)
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2
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Lin D, Guo Y, Chen X, Yang H, Li Q, Liu Q, Luo F, Meng K, Yang S, Cheng X, Ma W, Chen X, Wang M, Zhao Y. Identification and expression pattern of the sex determination gene fruitless-like in Cherax quadricarinatus. Comp Biochem Physiol B Biochem Mol Biol 2021; 259:110704. [PMID: 34920111 DOI: 10.1016/j.cbpb.2021.110704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 11/24/2021] [Accepted: 12/09/2021] [Indexed: 11/30/2022]
Abstract
The fruitless (fru) gene has an important function in the courtship behavior and sex determination pathway of Drosophila melanogaster; however, the fru gene has never been reported in shrimps. In this study, the fruitless-like gene was identified in Cherax quadricarinatus (Cqfru) and is reported here for the first time. A sequence analysis revealed a conserved BTB domain in Cqfru which is the same as fru in D. melanogaster. An analysis of the expression level of Cqfru showed that it was highly expressed in the gastrula stage during embryonic development. Furthermore, in situ hybridization and expression distribution in tissues showed that its sexually dimorphic expression may be focused on the hepatopancreas, brains, and gonads. The gonads, brains, and hepatopancreas of males had a higher expression level of Cqfru than those of females; however, the expression level of the abdominal ganglion was found to be higher in females than in males in this study. The results of an RNA interference treatment showed that a knockdown of Cqfru reduced the expression of the insulin-like androgenic gland hormone (IAG) and tumor necrosis factor (TNF). The characteristic fru gene in shrimps is reported here for the first time, with the results providing basic information for research into the sex-determination mechanism in C. quadricarinatus.
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Affiliation(s)
- Dawei Lin
- Tianjin Key Lab of Aqua-Ecology and Aquaculture, College of Fisheries, Tianjin Agricultural University, Tianjin 300384, China
| | - Yongjun Guo
- Tianjin Key Lab of Aqua-Ecology and Aquaculture, College of Fisheries, Tianjin Agricultural University, Tianjin 300384, China
| | - Xiuli Chen
- Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi Academy of Fisheries Sciences, Nanning, China
| | - Huizan Yang
- Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi Academy of Fisheries Sciences, Nanning, China
| | - Qiangyong Li
- Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi Academy of Fisheries Sciences, Nanning, China
| | - Qingyun Liu
- Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi Academy of Fisheries Sciences, Nanning, China
| | - Fuli Luo
- Tianjin Key Lab of Aqua-Ecology and Aquaculture, College of Fisheries, Tianjin Agricultural University, Tianjin 300384, China
| | - Kui Meng
- Tianjin Key Lab of Aqua-Ecology and Aquaculture, College of Fisheries, Tianjin Agricultural University, Tianjin 300384, China
| | - Songting Yang
- Tianjin Key Lab of Aqua-Ecology and Aquaculture, College of Fisheries, Tianjin Agricultural University, Tianjin 300384, China
| | - Xinquan Cheng
- Tianjin Key Lab of Aqua-Ecology and Aquaculture, College of Fisheries, Tianjin Agricultural University, Tianjin 300384, China
| | - Wenming Ma
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, Zhejiang 315100, People's Republic of China
| | - Xiaohan Chen
- Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi Academy of Fisheries Sciences, Nanning, China
| | - Moran Wang
- Tianjin Key Lab of Aqua-Ecology and Aquaculture, College of Fisheries, Tianjin Agricultural University, Tianjin 300384, China.
| | - Yongzhen Zhao
- Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi Academy of Fisheries Sciences, Nanning, China.
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Zhou H, Whitworth C, Pozmanter C, Neville MC, Van Doren M. Doublesex regulates fruitless expression to promote sexual dimorphism of the gonad stem cell niche. PLoS Genet 2021; 17:e1009468. [PMID: 33788836 PMCID: PMC8041189 DOI: 10.1371/journal.pgen.1009468] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 04/12/2021] [Accepted: 03/04/2021] [Indexed: 11/25/2022] Open
Abstract
Doublesex (Dsx) and Fruitless (Fru) are the two downstream transcription factors that actuate Drosophila sex determination. While Dsx assists Fru to regulate sex-specific behavior, whether Fru collaborates with Dsx in regulating other aspects of sexual dimorphism remains unknown. One important aspect of sexual dimorphism is found in the gonad stem cell (GSC) niches, where male and female GSCs are regulated to create large numbers of sperm and eggs. Here we report that Fru is expressed male-specifically in the GSC niche and plays important roles in the development and maintenance of these cells. Unlike previously-studied aspects of sex-specific Fru expression, which are regulated by Transformer (Tra)-mediated alternative splicing, we show that male-specific expression of fru in the gonad is regulated downstream of dsx, and is independent of tra. fru genetically interacts with dsx to support maintenance of the niche throughout development. Ectopic expression of fru inhibited female niche formation and partially masculinized the ovary. fru is also required autonomously for cyst stem cell maintenance and cyst cell survival. Finally, we identified a conserved Dsx binding site upstream of fru promoter P4 that regulates fru expression in the niche, indicating that fru is likely a direct target for transcriptional regulation by Dsx. These findings demonstrate that fru acts outside the nervous system to influence sexual dimorphism and reveal a new mechanism for regulating sex-specific expression of fru that is regulated at the transcriptional level by Dsx, rather than by alternative splicing by Tra. In animals, the process of sex determination controls the development of sexual dimorphism—the differences in appearance, physiology and behavior observed between males and females of a species. These differences are important for key functions such as sexual reproduction, and also influence other characteristics such as sex-specific disease progression. An important family of transcription factors, the Doublesex, mab-3 Related Transcription factors (DMRTs) control sex-specific development, particularly in the gonads, in most or all animals where they have been studied. Thus, an essential question in biology is how do the DMRTs control sex-specific development? In Drosophila, another set of transcription factors, encoded by the fruitless (fru) gene, controls sex-specific development of the nervous system and is thought to be regulated independently of the Drosophila DMRT Doublesex (Dsx). Here we present two important changes to our thinking about sexual development: 1) fru also acts to control sex-specific development outside the nervous system (in the gonad) and 2) sex-specific fru expression can be regulated by Dsx, in addition to its Dsx-independent regulation, providing a new mechanism for fru regulation that may be broadly utilized.
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Affiliation(s)
- Hong Zhou
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD, United States of America
| | - Cale Whitworth
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD, United States of America
| | - Caitlin Pozmanter
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD, United States of America
| | - Megan C. Neville
- Centre for Neural Circuits and Behaviour, University of Oxford, Tinsley Building, Mansfield Road, Oxford, United Kingdom
| | - Mark Van Doren
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD, United States of America
- * E-mail:
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Nguantad S, Chumnanpuen P, Thancharoen A, Vongsangnak W, Sriboonlert A. Identification of potential candidate genes involved in the sex determination cascade in an aquatic firefly, Sclerotia aquatilis (Coleoptera, Lampyridae). Genomics 2020; 112:2590-2602. [PMID: 32061895 DOI: 10.1016/j.ygeno.2020.01.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 01/13/2020] [Accepted: 01/23/2020] [Indexed: 12/27/2022]
Abstract
Sexual differentiation, dimorphism, and courtship behavior are the downstream developmental programs of the sex determination cascade. The sex determination cascade in arthropods often involves key genes, transformer (tra), doublesex (dsx), transformer-2 (tra2), and fruitless (fru). These genes are conserved among insect taxa; however, they have never been reported in fireflies. In this study, the candidate genes for these key genes were identified for the first time in an aquatic firefly, Sclerotia aquatilis using transcriptome analysis. A comparative protein-protein interaction (PPI) network of sex determination cascade was reconstructed for S. aquatilis based on a network of a model insect, Drosophila melanogaster. Subsequently, a sex determination cascade in S. aquatilis was proposed based on the amino acid sequence structures and expression profiles of these candidates. This study describes the first efforts toward understanding the molecular control of sex determination cascade in fireflies.
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Affiliation(s)
- Sarintip Nguantad
- Department of Zoology, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Pramote Chumnanpuen
- Department of Zoology, Faculty of Science, Kasetsart University, Bangkok, Thailand; Omics Center for Agriculture, Bioresources, Food, and Health, Kasetsart University (OmiKU), Bangkok 10900, Thailand
| | - Anchana Thancharoen
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - Wanwipa Vongsangnak
- Department of Zoology, Faculty of Science, Kasetsart University, Bangkok, Thailand; Omics Center for Agriculture, Bioresources, Food, and Health, Kasetsart University (OmiKU), Bangkok 10900, Thailand.
| | - Ajaraporn Sriboonlert
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand.
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5
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Watanabe T. Evolution of the neural sex-determination system in insects: does fruitless homologue regulate neural sexual dimorphism in basal insects? INSECT MOLECULAR BIOLOGY 2019; 28:807-827. [PMID: 31066110 DOI: 10.1111/imb.12590] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In the brain of holometabolous insects such as the fruit fly Drosophila melanogaster, the fruitless gene produces sex-specific gene products under the control of the sex-specific splicing cascade and contributes to the formation of the sexually dimorphic circuits. Similar sex-specific gene products of fruitless homologues have been identified in other holometabolous insects such as mosquitoes and a parasitic wasp, suggesting the fruitless-dependent neural sex-determination system is widely conserved amongst holometabolous insects. However, it remains obscure whether the fruitless-dependent neural sex-determination system is present in basal hemimetabolous insects. To address this issue, identification, characterization, and expression analyses of the fruitless homologue were conducted in the two-spotted cricket, Gryllus bimaculatus, as a model hemimetabolous insect. The Gryllus fruitless gene encodes multiple isoforms with a unique zinc finger domain, and does not encode a sex-specific gene product. The Gryllus Fruitless protein is broadly expressed in the neurones and glial cells in the brain, and there was no prominent sex-related difference in the expression levels of Gryllus fruitless isoforms. The results suggest that the Gryllus fruitless gene is not involved in the neural sex-determination in the cricket brain.
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Affiliation(s)
- T Watanabe
- Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Japan
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6
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Sex Determination Cascade in Insects: A Great Treasure House of Alternative Splicing. DIVERSITY AND COMMONALITY IN ANIMALS 2018. [DOI: 10.1007/978-4-431-56609-0_13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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7
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Pomerantz AF, Hoy MA, Kawahara AY. Molecular characterization and evolutionary insights into potential sex-determination genes in the western orchard predatory miteMetaseiulus occidentalis(Chelicerata: Arachnida: Acari: Phytoseiidae). J Biomol Struct Dyn 2014; 33:1239-53. [DOI: 10.1080/07391102.2014.941402] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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8
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The evolution of novelty in conserved genes; evidence of positive selection in the Drosophila fruitless gene is localised to alternatively spliced exons. Heredity (Edinb) 2013; 112:300-6. [PMID: 24149653 DOI: 10.1038/hdy.2013.106] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Revised: 08/30/2013] [Accepted: 09/24/2013] [Indexed: 11/08/2022] Open
Abstract
There has been much debate concerning whether cis-regulatory or coding changes are more likely to produce evolutionary innovation or adaptation in gene function, but an additional complication is that some genes can dramatically diverge through alternative splicing, increasing the diversity of gene function within a locus. The fruitless gene is a major transcription factor with a wide range of pleiotropic functions, including a fundamental conserved role in sexual differentiation, species-specific morphology and an important influence on male sexual behaviour. Here, we examine the structure of fruitless in multiple species of Drosophila, and determine the patterns of selective constraint acting across the coding region. We found that the pattern of selection, estimated from the ratio of non-synonymous to synonymous substitutions, varied considerably across the gene, with most regions of the gene evolutionarily conserved but with several regions showing evidence of divergence as a result of positive selection. The regions that showed evidence of positive selection were found to be localised to relatively consistent regions across multiple speciation events, and are associated with alternative splicing. Alternative splicing may thus provide a route to gene diversification in key regulatory loci.
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9
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Yamamoto D, Ishikawa Y. Genetic and Neural Bases for Species-Specific Behavior inDrosophilaSpecies. J Neurogenet 2013; 27:130-42. [DOI: 10.3109/01677063.2013.800060] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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10
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Salvemini M, D'Amato R, Petrella V, Aceto S, Nimmo D, Neira M, Alphey L, Polito LC, Saccone G. The orthologue of the fruitfly sex behaviour gene fruitless in the mosquito Aedes aegypti: evolution of genomic organisation and alternative splicing. PLoS One 2013; 8:e48554. [PMID: 23418412 PMCID: PMC3572092 DOI: 10.1371/journal.pone.0048554] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Accepted: 09/26/2012] [Indexed: 12/23/2022] Open
Abstract
In Drosophila melanogaster the doublesex (dsx) and fruitless (fru) regulatory genes act at the bottom of the somatic sex determination pathway. Both are regulated via alternative splicing by an upstream female-specific TRA/TRA-2 complex, recognizing a common cis element. dsx controls somatic sexual differentiation of non-neural as well as of neural tissues. fru, on the other hand, expresses male-specific functions only in neural system where it is required to built the neural circuits underlying proper courtship behaviour. In the mosquito Aedes aegypti sex determination is different from Drosophila. The key male determiner M, which is located on one of a pair of homomorphic sex chromosomes, controls sex-specific splicing of the mosquito dsx orthologue. In this study we report the genomic organization and expression of the fru homologue in Ae. aegypti (Aeafru). We found that it is sex-specifically spliced suggesting that it is also under the control of the sex determination pathway. Comparative analyses between the Aeafru and Anopheles gambiae fru (Angfru) genomic loci revealed partial conservation of exon organization and extensive divergence of intron lengths. We find that Aeadsx and Aeafru share novel cis splicing regulatory elements conserved in the alternatively spliced regions. We propose that in Aedes aegypti sex-specific splicing of dsx and fru is most likely under the control of splicing regulatory factors which are different from TRA and TRA-2 found in other dipteran insects and discuss the potential use of fru and dsx for developing new genetic strategies in vector control.
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Affiliation(s)
- Marco Salvemini
- Department of Biological Sciences - Section of Genetics and Molecular Biology, University of Naples Federico II, Naples, Italy.
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11
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Boerjan B, Tobback J, Vandersmissen HP, Huybrechts R, Schoofs L. Fruitless RNAi knockdown in the desert locust, Schistocerca gregaria, influences male fertility. JOURNAL OF INSECT PHYSIOLOGY 2012; 58:265-269. [PMID: 22138053 DOI: 10.1016/j.jinsphys.2011.11.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 11/18/2011] [Accepted: 11/21/2011] [Indexed: 05/31/2023]
Abstract
In Drosophila melanogaster, the male-specific splice isoform of the fruitless gene (Fru(M)) encodes a set of transcription factors that are involved in the regulation of male courtship and copulation. Recent insights from non-drosophilid insects suggest a conserved evolutionary role for the transcription factor Fruitless. In the desert locust, Schistocerca gregaria and the German cockroach, Blatella germanica, both orthopteran insects, a conserved functional role for fruitless has been proposed. Fru specific RNAi knockdown in the third nymphal stage of male Schistocera gregaria delays copulation initiation and results in reduced progeny. In order to identify the origin of the observed phenotypic effects following a fruitless RNAi treatment in the male, we show that the fru knockdown has no detectable effect on spermio- or spermatogenesis and on the transfer of spermatozoa during copulation. Nevertheless, it is clear that the male seminal vesicles contain significantly less spermatozoa after fru RNAi as compared to gfp RNAi controls. We conclude that a lowered male fertility, caused by the fru knockdown in male desert locusts may be the direct cause for the reduction of the progeny numbers in their naïve female copulation partners.
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Affiliation(s)
- Bart Boerjan
- Research Group Functional Genomics and Proteomics, K.U. Leuven, Naamsestraat 59, 3000 Leuven, Belgium.
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12
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Boerjan B, Tobback J, De Loof A, Schoofs L, Huybrechts R. Fruitless RNAi knockdown in males interferes with copulation success in Schistocerca gregaria. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2011; 41:340-347. [PMID: 21296153 DOI: 10.1016/j.ibmb.2011.01.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/17/2011] [Accepted: 01/24/2011] [Indexed: 05/30/2023]
Abstract
In Drosophila melanogaster, the male-specific splice isoform of the fruitless gene (Fru(M)) codes for a set of transcription factors that are involved in the regulation of male courtship and copulation. Fru(M) is expressed in an interconnected neuronal circuit containing central and sensory neurons as well as motor neurons. A partial sequence from the Schistocerca gregaria fru-gene from an EST database allowed quantitative real time analysis of fru-expression in adult locusts, and revealed the highest expression in the testes, accessory glands as well as the brain (and optic lobes). Starting fru specific RNAi knockdown in the third and fourth nymphal stage resulted in a significantly lower cumulative copulation frequency of the RNAi-treated animals compared to controls after 3 h of observation. In addition, the testes of RNAi-treated males weigh less. Analysis of the egg pods resulting from a successful copulation event revealed that egg pods from females that mated with an RNAi-treated male were smaller and contained less fertilized eggs compared to egg pods from females who mated with control males. Starting injections in the fifth nymphal stage showed the complete opposite for the cumulative copulation frequency and testes weight. We conclude that already in the early nymphal phases of male desert locusts, fruitless starts to play an important role in the regulation of successful copulation in the adult. The RNAi treatment in the male has also its effects on fertility and fecundity. It remains unknown whether this effect is coming from aberrant courtship behaviour or from an altered composition of the sperm or seminal fluids.
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Affiliation(s)
- Bart Boerjan
- Research Group Functional Genomics and Proteomics, K.U. Leuven, Naamsestraat 59, Leuven, Belgium.
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Clynen E, Ciudad L, Bellés X, Piulachs MD. Conservation of fruitless' role as master regulator of male courtship behaviour from cockroaches to flies. Dev Genes Evol 2011; 221:43-8. [PMID: 21340608 DOI: 10.1007/s00427-011-0352-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Accepted: 01/31/2011] [Indexed: 11/29/2022]
Abstract
In Drosophila melanogaster, male courtship behaviour is regulated by the fruitless gene. In D. melanogaster, fruitless encodes a set of putative transcription factors that are sex-specifically spliced. Male-specific variants are necessary and sufficient to elicit male courtship behaviour. Fruitless sequences have been reported in other insect species, but there are no data available on their functional role. In the present work, we cloned and sequenced fruitless in males of the German cockroach, Blattella germanica, and we studied its expression in male brain and testes. B. germanica fruitless encodes a 350-amino acid protein with BTB and Zinc finger domains typical of fruitless sequences. Upon RNAi-mediated knockdown of fruitless in B. germanica, males no longer exhibit courtship behaviour, thus implying that fruitless is necessary for male sexual behaviour in our cockroach model. This suggests that the role of fruitless as master regulator of male sexual behaviour has been conserved along insect evolution, at least from cockroaches to flies.
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Affiliation(s)
- Elke Clynen
- Institute of Evolutionary Biology (CSIC-UPF), Passeig Marítim de la Barceloneta 37, 08003, Barcelona, Spain
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Salvemini M, Polito C, Saccone G. Fruitless alternative splicing and sex behaviour in insects: an ancient and unforgettable love story? J Genet 2011; 89:287-99. [PMID: 20876995 DOI: 10.1007/s12041-010-0040-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Courtship behaviours are common features of animal species that reproduce sexually. Typically, males are involved in courting females. Insects display an astonishing variety of courtship strategies primarily based on innate stereotyped responses to various external stimuli. In Drosophila melanogaster, male courtship requires proteins encoded by the fruitless (fru) gene that are produced in different sex-specific isoforms via alternative splicing. Drosophila mutant flies with loss-of-function alleles of the fru gene exhibit blocked male courtship behaviour. However, various individual steps in the courtship ritual are disrupted in fly strains carrying different fru alleles. These findings suggest that fru is required for specific steps in courtship. In distantly related insect species, various fru paralogues were isolated, which shows conservation of sex-specific alternative splicing and protein expression in neural tissues and suggests an evolutionary functional conservation of fru in the control of male-specific courtship behaviour. In this review, we report the seminal findings regarding the fru gene, its splicing regulation and evolution in insects.
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Affiliation(s)
- Marco Salvemini
- Department of Biological Sciences, University of Naples Federico II, 80134, Naples, Italy
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15
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Bertossa RC, van de Zande L, Beukeboom LW. The Fruitless gene in Nasonia displays complex sex-specific splicing and contains new zinc finger domains. Mol Biol Evol 2009; 26:1557-69. [PMID: 19349644 DOI: 10.1093/molbev/msp067] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The transcription factor Fruitless exerts a broad range of functions during Drosophila development, the most apparent of which is the determination of sexual behavior in males. Although fruitless sequences are found in other insect orders, little is known about fruitless structure and function outside Diptera. We have performed a thorough analysis of fruitless transcripts in the haplo-diploid wasp Nasonia vitripennis and found both sex-specific and non-sex-specific transcripts similar to those found in Drosophila. In Nasonia, however, a novel, large fruitless transcript is present in females only. Putative binding sites for sex-specific splicing factors found in Nasonia fruitless and doublesex as well as Apis mellifera doublesex transcripts were sufficient to identify a corresponding female-specific fruitless exon in A. mellifera, suggesting that similar factors in both hymenopteran species could be responsible for sex-specific splicing of both genes. Furthermore, new C(2)H(2) zinc finger domains found in Nasonia fruitless transcripts were also identified in the fruitless locus of major holometabolous insect species but not in drosophilids. Conservation of important domains and sex-specific splicing in Diptera and Hymenoptera support the hypothesis that fruitless is an ancient gene and has conserved functions in insects. Considerable divergences in other parts of the gene are expected to underlie species-specific differences and may help to explain diversity observed in insect sexual behaviors.
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Affiliation(s)
- Rinaldo C Bertossa
- Evolutionary Genetics, Centre for Ecological and Evolutionary Studies, The Netherlands.
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