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Jiao Y, Sengodan K, Chen J, Palli SR. Role of histone methylation in insect development: KMT5A regulates ecdysteroid biosynthesis during metamorphosis of Tribolium castaneum. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2025; 180:104316. [PMID: 40287070 PMCID: PMC12066215 DOI: 10.1016/j.ibmb.2025.104316] [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: 01/29/2025] [Revised: 04/09/2025] [Accepted: 04/23/2025] [Indexed: 04/29/2025]
Abstract
Methylation levels of core histones play important roles in the regulation of gene expression and impact animal development. However, the methyltransferases and demethylases that determine histone methylation levels remain largely unexplored in insects. Most of our current understanding of histone methylation comes from mammalian studies. In this study, we first identified potential histone methyltransferases and demethylases encoded in the genome of the red flour beetle Tribolium castaneum. The function of these histone methylation enzymes in the metamorphosis was investigated by knocking down genes coding for these enzymes using RNA interference (RNAi). Our results showed that a lysine methyltransferase, KMT5A, plays a critical role in T. castaneum metamorphosis by regulating the biosynthesis of ecdysteroids. Treating KMT5A-knockdown larvae with 20 hydroxyecdysone can partially rescue T. castaneum pupation. Western blot analysis showed that KMT5A catalyzes H4K20 mono-methylation. However, further studies suggest that KMT5A may regulate T. castaneum pupation through mechanisms independent of H4K20 methylation. These data uncovered the roles of histone methylation enzymes in T. castaneum metamorphosis and KMT5A as a critical regulator of ecdysteroid biosynthesis.
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Affiliation(s)
- Yaoyu Jiao
- Department of Entomology, Martin-Gatton College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY, 40546, USA.
| | - Karthi Sengodan
- Department of Entomology, Martin-Gatton College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY, 40546, USA
| | - Jiasheng Chen
- Department of Entomology, Martin-Gatton College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY, 40546, USA
| | - Subba Reddy Palli
- Department of Entomology, Martin-Gatton College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY, 40546, USA.
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Hill V, Williams L, Salter A, Brameld J, Parr T. Octopamine alters yellow mealworm body composition. Animal 2025; 19:101490. [PMID: 40222199 DOI: 10.1016/j.animal.2025.101490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2024] [Revised: 03/04/2025] [Accepted: 03/10/2025] [Indexed: 04/15/2025] Open
Abstract
There is the potential to increase the production yield within the emerging insect industry in order to produce high-quality, sustainable protein. In invertebrates, the monoamine, octopamine (OA), has a similar role to that of noradrenaline in mammals. Beta-2 adrenergic agonists increase protein and decrease fat deposition in mammals, thereby inducing favourable changes in body composition. We hypothesised that OA would have similar effects in insects. Tenebrio molitor larvae, commonly called yellow mealworms, were fed for 35 days on either control wheat bran or wheat bran containing OA at 5 μg OA/g. There were trends for treatment × time interactions for mealworm group weight (P = 0.075) and individual mealworm weight (P = 0.069), with the OA group becoming heavier/bigger after 18 days. In addition, there was a trend for a treatment × time interaction on cumulative pupation (P = 0.099), with OA-treated mealworms having delayed pupation. After 35 days of OA treatment, there were significant effects on mealworm final body proximate nutrient composition on a DM basis, with fat content being significantly decreased (by 8%, P = 0.006), whilst CP was significantly increased (by 6%, P = 0.019) in OA-treated mealworms compared to control. There was little effect of OA on the fatty acid composition of the mealworms, with small reductions in palmitoleic acid (P < 0.001) and oleic acid (P = 0.082). Despite a significant increase in protein content with OA treatment, SDS-PAGE did not reveal any changes in the proteins being expressed. Hence, OA treatment of mealworms resulted in an increase in the proportion of protein and a decrease in fat, demonstrating that mealworm nutrient composition can potentially be manipulated to provide a higher-value feed ingredient.
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Affiliation(s)
- V Hill
- School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | - L Williams
- School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | - A Salter
- School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | - J Brameld
- School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK; Food Systems Institute, University of Nottingham, Nottingham NG7 2RD, UK
| | - T Parr
- School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK; Food Systems Institute, University of Nottingham, Nottingham NG7 2RD, UK.
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Liu C, Wu MZ, Zheng ZJ, Fan ST, Tan JF, Jiao Y, Palli SR, Zhu GH. Knockout BR-C induces premature expression of E93 thus triggering adult differentiation under larval morphology. PEST MANAGEMENT SCIENCE 2025; 81:1923-1933. [PMID: 39641237 DOI: 10.1002/ps.8592] [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: 10/07/2024] [Revised: 11/21/2024] [Accepted: 11/22/2024] [Indexed: 12/07/2024]
Abstract
BACKGROUND Holometabolan pupal-specifier broad-complex (BR-C) and adult specifier ecdysone-induced protein 93F (E93) are essential for metamorphosis; however, their interaction and effects on programmed cell death and cell differentiation during pupation remain unclear. RESULTS Here, multiple single-guide RNA (sgRNA)-mediated mosaic knockout of BR-C induced a deformed larva/pupa intermediate phenotype in Spodoptera frugiperda. Quantitative real-time polymerase chain reaction (qPCR) analysis showed that the adult specifier E93 was prematurely expressed in the BR-C mutants during the penultimate and last instar larval stages. Additionally, histological observation and TUNEL assay showed that apoptosis in the fat body and midgut was activated in the larval tissues; astonishingly, the adult midgut appeared in the pupae of BR-C mutants. CONCLUSION Overall, the results demonstrated that the premature expression of E93 induced by lack of BR-C triggers adult differentiation during the larval stages, which revealed the inhibitory effect of BR-C on E93 during metamorphosis in S. frugiperda. © 2024 Society of Chemical Industry.
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Affiliation(s)
- Chang Liu
- School of Agriculture and Biotechnology, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
- State Key Laboratory of Biocontrol, School of Agriculture and Biotechnology, Sun Yat-sen University, Shenzhen, China
| | - Mian-Zhi Wu
- School of Agriculture and Biotechnology, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
- State Key Laboratory of Biocontrol, School of Agriculture and Biotechnology, Sun Yat-sen University, Shenzhen, China
| | - Zi-Jing Zheng
- School of Agriculture and Biotechnology, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
- State Key Laboratory of Biocontrol, School of Agriculture and Biotechnology, Sun Yat-sen University, Shenzhen, China
| | - Shu-Ting Fan
- School of Agriculture and Biotechnology, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
- State Key Laboratory of Biocontrol, School of Agriculture and Biotechnology, Sun Yat-sen University, Shenzhen, China
| | - Jin-Fang Tan
- School of Agriculture and Biotechnology, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
- State Key Laboratory of Biocontrol, School of Agriculture and Biotechnology, Sun Yat-sen University, Shenzhen, China
| | - Yaoyu Jiao
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
| | - Subba Reddy Palli
- Department of Entomology, College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY, USA
| | - Guan-Heng Zhu
- School of Agriculture and Biotechnology, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
- State Key Laboratory of Biocontrol, School of Agriculture and Biotechnology, Sun Yat-sen University, Shenzhen, China
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Kawamoto K, Ishimaru Y, Tomonari S, Watanabe T, Noji S, Mito T. Myoglianin is a crucial factor for the transition to the juvenile hormone-dependent phase during hemimetabolous nymphal development. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2025; 178:104274. [PMID: 39947524 DOI: 10.1016/j.ibmb.2025.104274] [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: 10/08/2024] [Revised: 02/07/2025] [Accepted: 02/07/2025] [Indexed: 02/18/2025]
Abstract
In hemimetabolous insects, the developmental process of nymphs is divided into three growth phases, i.e., juvenile hormone (JH)-independent, JH-dependent, and JH-free phases. The wing primordium in hemimetabolous insects is formed latently in the JH-independent phase and manifests and grows in the JH-dependent phase. Myoglianin (Myo) is known to be a key factor of metamorphosis in the JH-free phase of nymphs, regulating negatively JH synthesis. Here we find the role of Myo in earlier phases in the cricket Gryllus bimaculatus via gene knockout analysis using CRISPR/Cas9. In the myo knockout (KO) mutants, developmental delay during embryogenesis was observed, and nymphal body size and the timing of molting were affected. The KO nymphs underwent multiple molts, typically around seven, but remained significantly smaller in body size compared to wild-type individuals. The KO nymphs also did not exhibit the expected growth of wing primordia, implying that transition to JH-dependent phase was failed. This failure in phase transition could have been caused by excessive JH because titers of JH I and JH II were remarkably increased in the KO mutants. Our results suggest that Myo plays a crucial role not only in regulating timing of molting but also in the transition to the nymphal growth phases associated with growth of wing primordia and nymphal body size.
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Affiliation(s)
- Kohei Kawamoto
- Graduate School of Advanced Technology and Science, Tokushima University, Tokushima, Japan
| | - Yoshiyasu Ishimaru
- Graduate School of Sciences and Technology for Innovation, Tokushima University, Tokushima, Japan
| | - Sayuri Tomonari
- Technical Support Department, Tokushima University, Tokushima, Japan
| | - Takahito Watanabe
- Bio-Innovation Research Center, Tokushima University, Tokushima, Japan
| | - Sumihare Noji
- Bio-Innovation Research Center, Tokushima University, Tokushima, Japan
| | - Taro Mito
- Bio-Innovation Research Center, Tokushima University, Tokushima, Japan.
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Konopová B. Evolution of insect metamorphosis - an update. CURRENT OPINION IN INSECT SCIENCE 2025; 67:101289. [PMID: 39490982 DOI: 10.1016/j.cois.2024.101289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2024] [Revised: 10/18/2024] [Accepted: 10/22/2024] [Indexed: 11/05/2024]
Abstract
Metamorphosis endowed the insects with properties that enabled them to conquer the Earth. It is a hormonally controlled morphogenetic process that transforms the larva into the adult. Metamorphosis appeared with the origin of wings and flight. The sesquiterpenoid juvenile hormone (JH) suppresses wing morphogenesis and ensures that metamorphosis takes place at the right ontogenetic time. This review explores the origin of insect metamorphosis and the ancestral function of JH. Fossil record shows that the first Paleozoic winged insects had (hemimetabolous) metamorphosis, and their larvae were likely aquatic. In the primitive wingless silverfish that lacks metamorphosis, JH is essential for late embryogenesis and reproduction. JH production after the embryo dorsal closure promotes hatching and terminal tissue maturation.
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Affiliation(s)
- Barbora Konopová
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic.
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Wu MZ, Fan ST, Zhang YC, Tan JF, Zhu GH. Disrupting shadow in the prothoracic gland induced larval development arrest in the fall armyworm Spodoptera frugiperda. Front Physiol 2024; 15:1502753. [PMID: 39722728 PMCID: PMC11668756 DOI: 10.3389/fphys.2024.1502753] [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: 09/27/2024] [Accepted: 10/30/2024] [Indexed: 12/28/2024] Open
Abstract
Introduction The juvenile hormone (JH) and 20-hydroxyecdysone (20E) are the central regulating hormones of insect development. The timing of their secretion usually leads to developmental transitions. Methods The developmental transitions were evaluated via the starvation treatment and the expressions of two key metamorphosis inducing factor in Spodoptera frugiperda. Then, the main endocrine organs, including the brain-corpora cardiacum-corpora allatum and prothoracic gland, were sampled from L4-24 h and L6-24 h larvae for the RNA-seq analysis. Additionally, the critical rate-limiting enzyme of 20E synthesis, shadow, was knocked down to mimic the downregulation of 20E synthesis in the late larval instar. Results The critical weight (CW), when JH titer declines for metamorphosis, was determined be approximately L6-24 h in S. frugiperda. However, the expression of the pupal specifier Broad-Complex and the potential "metamorphosis initiation factor" Myoglianin showed a stepwise increase between L4-24 h and L6-24 h, suggesting that the developmental transitions may occur earlier. The RNA-seq analysis revealed that both 20E and JH synthesis enzymes were downregulated at the CW. In addition, strong tendencies in the expression pattern were detected among the lists of transcripts. Further knockdown of shadow induced larval development arrest and subsequent mortality, indicating that disrupting 20E synthesis before the CW is lethal. Besides, JH synthesis enzyme was down-regulated. Conclusion The downregulation of 20E synthesis enzymes at the CW may represent a carefully regulated event, suggesting a deceleration of larval growth and the initiation of some underlying physiological changes to set the stage for metamorphosis.
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Affiliation(s)
- Mian-Zhi Wu
- School of Agriculture and Biotechnology, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
- State Key Laboratory of Biocontrol, School of Agriculture and Biotechnology, Sun Yat-sen University, Shenzhen, China
| | - Shu-Ting Fan
- School of Agriculture and Biotechnology, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
- State Key Laboratory of Biocontrol, School of Agriculture and Biotechnology, Sun Yat-sen University, Shenzhen, China
| | - Yuan-Chen Zhang
- College of Biology and Food Engineering, Anyang Institute of Technology, Anyang, China
| | - Jin-Fang Tan
- School of Agriculture and Biotechnology, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
- State Key Laboratory of Biocontrol, School of Agriculture and Biotechnology, Sun Yat-sen University, Shenzhen, China
| | - Guan-Heng Zhu
- School of Agriculture and Biotechnology, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
- State Key Laboratory of Biocontrol, School of Agriculture and Biotechnology, Sun Yat-sen University, Shenzhen, China
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7
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Anjum AA, Lin MJ, Jin L, Li GQ. A critical role for the nuclear protein Akirin in larval development in Henosepilachna vigintioctopunctata. INSECT MOLECULAR BIOLOGY 2024; 33:650-661. [PMID: 38783592 DOI: 10.1111/imb.12929] [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: 10/11/2023] [Accepted: 05/04/2024] [Indexed: 05/25/2024]
Abstract
Akirin is a nuclear protein that controls development in vertebrates and invertebrates. The function of Akirin has not been assessed in any Coleopteran insects. We found that high levels of akirin transcripts in Henosepilachna vigintioctopunctata, a serious Coleopteran potato defoliator (hereafter Hvakirin), were present at prepupal, pupal and adult stages, especially in larval foregut and fat body. RNA interference (RNAi) targeting Hvakirin impaired larval development. The Hvakirin RNAi larvae arrested development at the final larval instar stage. They remained as stunted larvae, gradually blackened and finally died. Moreover, the remodelling of gut and fat body was inhibited in the Hvakirin depleted larvae. Two layers of cuticles, old and newly formed, were noted in the dsegfp-injected animals. In contrast, only a layer of cuticle was found in the dsakirin-injected beetles, indicating the arrest of larval development. Furthermore, the expression of three transforming growth factor-β cascade genes (Hvsmox, Hvmyo and Hvbabo), a 20-hydroxyecdysone (20E) receptor gene (HvEcR) and six 20E response genes (HvHR3, HvHR4, HvE75, HvBrC, HvE93 and Hvftz-f1) was significantly repressed, consistent with decreased 20E signalling. Conversely, the transcription of a juvenile hormone (JH) biosynthesis gene (Hvjhamt), a JH receptor gene (HvMet) and two JH response genes (HvKr-h1 and HvHairy) was greatly enhanced. Our findings suggest a critical role of Akirin in larval development in H. vigintioctopunctata.
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Affiliation(s)
- Ahmad Ali Anjum
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests/State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Meng-Jiao Lin
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests/State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Lin Jin
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests/State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Guo-Qing Li
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests/State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
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8
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Truman JW, Riddiford LM, Konopova B, Nouzova M, Noriega FG, Herko M. The embryonic role of juvenile hormone in the firebrat, Thermobia domestica, reveals its function before its involvement in metamorphosis. eLife 2024; 12:RP92643. [PMID: 38568859 PMCID: PMC10994664 DOI: 10.7554/elife.92643] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024] Open
Abstract
To gain insights into how juvenile hormone (JH) came to regulate insect metamorphosis, we studied its function in the ametabolous firebrat, Thermobia domestica. Highest levels of JH occur during late embryogenesis, with only low levels thereafter. Loss-of-function and gain-of-function experiments show that JH acts on embryonic tissues to suppress morphogenesis and cell determination and to promote their terminal differentiation. Similar embryonic actions of JH on hemimetabolous insects with short germ band embryos indicate that JH's embryonic role preceded its derived function as the postembryonic regulator of metamorphosis. The postembryonic expansion of JH function likely followed the evolution of flight. Archaic flying insects were considered to lack metamorphosis because tiny, movable wings were evident on the thoraces of young juveniles and their positive allometric growth eventually allowed them to support flight in late juveniles. Like in Thermobia, we assume that these juveniles lacked JH. However, a postembryonic reappearance of JH during wing morphogenesis in the young juvenile likely redirected wing development to make a wing pad rather than a wing. Maintenance of JH then allowed wing pad growth and its disappearance in the mature juvenile then allowed wing differentiation. Subsequent modification of JH action for hemi- and holometabolous lifestyles are discussed.
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Affiliation(s)
- James W Truman
- Friday Harbor Laboratories, University of WashingtonFriday HarborUnited States
- Department of Biology, University of WashingtonSeattleUnited States
| | - Lynn M Riddiford
- Friday Harbor Laboratories, University of WashingtonFriday HarborUnited States
- Department of Biology, University of WashingtonSeattleUnited States
| | - Barbora Konopova
- Department of Zoology, Faculty of Science, University of South BohemiaCeske BudejoviceCzech Republic
- Institute of Entomology, Biology Centre of the Czech Academy of SciencesCeske BudejoviceCzech Republic
| | - Marcela Nouzova
- Institute of Parasitology, Biology Centre of the Czech Academy of SciencesCeske BudejoviceCzech Republic
| | - Fernando G Noriega
- Department of Biological Sciences and BSI, Florida International UniversityMiamiUnited States
- Department of Parasitology, Faculty of Science, University of South BohemiaCeské BudejoviceCzech Republic
| | - Michelle Herko
- Friday Harbor Laboratories, University of WashingtonFriday HarborUnited States
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9
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Truman JW, Riddiford LM, Konopová B, Nouzova M, Noriega FG, Herko M. The embryonic role of juvenile hormone in the firebrat, Thermobia domestica, reveals its function before its involvement in metamorphosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.06.561279. [PMID: 37873170 PMCID: PMC10592639 DOI: 10.1101/2023.10.06.561279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
To gain insights into how juvenile hormone (JH) came to regulate insect metamorphosis, we studied its function in the ametabolous firebrat, Thermobia domestica. Highest levels of JH occur during late embryogenesis, with only low levels thereafter. Loss-of-function and gain-of-function experiments show that JH acts on embryonic tissues to suppress morphogenesis and cell determination and to promote their terminal differentiation. Similar embryonic actions of JH on hemimetabolous insects with short germ band embryos indicate that JH's embryonic role preceded its derived function as the postembryonic regulator of metamorphosis. The postembryonic expansion of JH function likely followed the evolution of flight. Archaic flying insects were considered to lack metamorphosis because tiny, movable wings were evident on the thoraces of young juveniles and their positive allometric growth eventually allowed them to support flight in late juveniles. Like in Thermobia, we assume that these juveniles lacked JH. However, a postembryonic reappearance of JH during wing morphogenesis in the young juvenile likely redirected wing development to make a wing pad rather than a wing. Maintenance of JH then allowed wing pad growth and its disappearance in the mature juvenile then allowed wing differentiation. Subsequent modification of JH action for hemi- and holometabolous lifestyles are discussed.
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Affiliation(s)
- James W. Truman
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA, USA
- Department of Biology, University of Washington, Seattle, WA USA
| | - Lynn M. Riddiford
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA, USA
- Department of Biology, University of Washington, Seattle, WA USA
| | - Barbora Konopová
- Department of Zoology, Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Marcela Nouzova
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Fernando G. Noriega
- Department of Biological Sciences and BSI, Florida International University, FL ,USA
- Department of Parasitology, Faculty of Science, University of South Bohemia, Ceské Budejovice, Czech Republic
| | - Michelle Herko
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA, USA
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10
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Tyson JJ, Monshizadeh A, Shvartsman SY, Shingleton AW. A dynamical model of growth and maturation in Drosophila. Proc Natl Acad Sci U S A 2023; 120:e2313224120. [PMID: 38015844 PMCID: PMC10710029 DOI: 10.1073/pnas.2313224120] [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: 08/28/2023] [Accepted: 10/12/2023] [Indexed: 11/30/2023] Open
Abstract
The decision to stop growing and mature into an adult is a critical point in development that determines adult body size, impacting multiple aspects of an adult's biology. In many animals, growth cessation is a consequence of hormone release that appears to be tied to the attainment of a particular body size or condition. Nevertheless, the size-sensing mechanism animals use to initiate hormone synthesis is poorly understood. Here, we develop a simple mathematical model of growth cessation in Drosophila melanogaster, which is ostensibly triggered by the attainment of a critical weight (CW) early in the last instar. Attainment of CW is correlated with the synthesis of the steroid hormone ecdysone, which causes a larva to stop growing, pupate, and metamorphose into the adult form. Our model suggests that, contrary to expectation, the size-sensing mechanism that initiates metamorphosis occurs before the larva reaches CW; that is, the critical-weight phenomenon is a downstream consequence of an earlier size-dependent developmental decision, not a decision point itself. Further, this size-sensing mechanism does not require a direct assessment of body size but emerges from the interactions between body size, ecdysone, and nutritional signaling. Because many aspects of our model are evolutionarily conserved among all animals, the model may provide a general framework for understanding how animals commit to maturing from their juvenile to adult form.
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Affiliation(s)
- John J. Tyson
- Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, VA24061
| | - Amirali Monshizadeh
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL60607
| | - Stanislav Y. Shvartsman
- Department of Molecular Biology, Princeton University, Princeton, NJ08544
- Center for Computational Biology, Flatiron Institute, Simons Foundation, New York City, NY10010
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Chafino S, Salvia R, Cruz J, Martín D, Franch-Marro X. TGFß/activin-dependent activation of Torso controls the timing of the metamorphic transition in the red flour beetle Tribolium castaneum. PLoS Genet 2023; 19:e1010897. [PMID: 38011268 PMCID: PMC10703416 DOI: 10.1371/journal.pgen.1010897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 12/07/2023] [Accepted: 11/10/2023] [Indexed: 11/29/2023] Open
Abstract
Understanding the mechanisms governing body size attainment during animal development is of paramount importance in biology. In insects, a crucial phase in determining body size occurs at the larva-pupa transition, marking the end of the larval growth period. Central to this process is the attainment of the threshold size (TS), a critical developmental checkpoint that must be reached before the larva can undergo metamorphosis. However, the intricate molecular mechanisms by which the TS orchestrates this transition remain poor understood. In this study, we investigate the role of the interaction between the Torso and TGFß/activin signaling pathways in regulating metamorphic timing in the red flour beetle, Tribolium castaneum. Our results show that Torso signaling is required specifically during the last larval instar and that its activation is mediated not only by the prothoracicotropic hormone (Tc-Ptth) but also by Trunk (Tc-Trk), another ligand of the Tc-Torso receptor. Interestingly, we show that while Tc-Torso activation by Tc-Ptth determines the onset of metamorphosis, Tc-Trk promotes growth during the last larval stage. In addition, we found that the expression of Tc-torso correlates with the attainment of the TS and the decay of juvenile hormone (JH) levels, at the onset of the last larval instar. Notably, our data reveal that activation of TGFß/activin signaling pathway at the TS is responsible for repressing the JH synthesis and inducing Tc-torso expression, initiating metamorphosis. Altogether, these findings shed light on the pivotal involvement of the Ptth/Trunk/Torso and TGFß/activin signaling pathways as critical regulatory components orchestrating the TS-driven metamorphic initiation, offering valuable insights into the mechanisms underlying body size determination in insects.
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Affiliation(s)
- Sílvia Chafino
- Institute of Evolutionary Biology (IBE, CSIC-Universitat Pompeu Fabra), Barcelona, Catalonia, Spain
| | - Roser Salvia
- Institute of Evolutionary Biology (IBE, CSIC-Universitat Pompeu Fabra), Barcelona, Catalonia, Spain
| | - Josefa Cruz
- Institute of Evolutionary Biology (IBE, CSIC-Universitat Pompeu Fabra), Barcelona, Catalonia, Spain
| | - David Martín
- Institute of Evolutionary Biology (IBE, CSIC-Universitat Pompeu Fabra), Barcelona, Catalonia, Spain
| | - Xavier Franch-Marro
- Institute of Evolutionary Biology (IBE, CSIC-Universitat Pompeu Fabra), Barcelona, Catalonia, Spain
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Li J, Lyu B, Song Q. TGF-β Type II Receptor Punt Suppresses Antimicrobial Peptide Expression and Influences Development in Tribolium castaneum. INSECTS 2023; 14:515. [PMID: 37367331 DOI: 10.3390/insects14060515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 05/26/2023] [Accepted: 05/31/2023] [Indexed: 06/28/2023]
Abstract
The transforming growth factor-β (TGF-β) superfamily in insects regulated various physiological events, including immune response, growth and development, and metamorphosis. This complex network of signaling pathways involves conserved cell-surface receptors and signaling co-receptors that allow for precisely coordinated cellular events. However, the roles of TGF-β receptors, particularly the type II receptor Punt, in mediating the innate immunity in insects remains unclear. In this study, we used the red flour beetle, Tribolium castaneum, as a model species to investigate the role of TGF-β type II receptor Punt in mediating antimicrobial peptide (AMP) expression. Developmental and tissue-specific transcript profiles revealed Punt was constitutively expressed throughout development, with the highest transcript level in 1-day female pupae and the lowest transcript level in 18-day larvae. Tissue specific expression profiles showed the highest transcript level of Punt was observed in the Malpighian tubule and ovary in 18-day larvae and 1-day female adults, respectively, suggesting Punt might have distinct functions in larvae and adults. Further results indicated that Punt RNAi in the 18-day larvae led to increased transcript level of AMP genes through transcription factor Relish, leading to inhibition of Escherichia coli proliferation. Knockdown of Punt in larvae also led to splitting of adult elytra and abnormal compound eyes. Furthermore, knockdown of Punt during the female pupal stage resulted in increased transcript levels of AMP genes, as well as abnormal ovary, reduced fecundity, and failure of eggs to hatch. This study deepens our understanding of the biological significance of Punt in insect TGF-β signaling and lays the groundwork for further research of its role in insect immune response, development, and reproduction.
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Affiliation(s)
- Jingjing Li
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
| | - Bo Lyu
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
| | - Qisheng Song
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
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13
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Truman JW, Riddiford LM. Drosophila postembryonic nervous system development: a model for the endocrine control of development. Genetics 2023; 223:iyac184. [PMID: 36645270 PMCID: PMC9991519 DOI: 10.1093/genetics/iyac184] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 12/13/2022] [Indexed: 01/17/2023] Open
Abstract
During postembryonic life, hormones, including ecdysteroids, juvenile hormones, insulin-like peptides, and activin/TGFβ ligands act to transform the larval nervous system into an adult version, which is a fine-grained mosaic of recycled larval neurons and adult-specific neurons. Hormones provide both instructional signals that make cells competent to undergo developmental change and timing cues to evoke these changes across the nervous system. While touching on all the above hormones, our emphasis is on the ecdysteroids, ecdysone and 20-hydroxyecdysone (20E). These are the prime movers of insect molting and metamorphosis and are involved in all phases of nervous system development, including neurogenesis, pruning, arbor outgrowth, and cell death. Ecdysteroids appear as a series of steroid peaks that coordinate the larval molts and the different phases of metamorphosis. Each peak directs a stereotyped cascade of transcription factor expression. The cascade components then direct temporal programs of effector gene expression, but the latter vary markedly according to tissue and life stage. The neurons read the ecdysteroid titer through various isoforms of the ecdysone receptor, a nuclear hormone receptor. For example, at metamorphosis the pruning of larval neurons is mediated through the B isoforms, which have strong activation functions, whereas subsequent outgrowth is mediated through the A isoform through which ecdysteroids play a permissive role to allow local tissue interactions to direct outgrowth. The major circulating ecdysteroid can also change through development. During adult development ecdysone promotes early adult patterning and differentiation while its metabolite, 20E, later evokes terminal adult differentiation.
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Affiliation(s)
- James W Truman
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA
- Department of Biology, University of Washington, Box 351800, Seattle, WA 98195, USA
| | - Lynn M Riddiford
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA
- Department of Biology, University of Washington, Box 351800, Seattle, WA 98195, USA
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14
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Chen F, Zhang XQ, Wu JJ, Jin L, Li GQ. Requirement of Myoglianin for metamorphosis in the beetle Henosepilachna vigintioctopunctata. INSECT MOLECULAR BIOLOGY 2022; 31:671-685. [PMID: 35661293 DOI: 10.1111/imb.12795] [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: 12/07/2021] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
Henosepilachna vigintioctopunctata is a serious defoliating beetle attacking Solanaceae and Cucurbitaceae plants in many Asian countries. In the present paper, we identified a putative myoglianin (myo) gene. Hvmyo was actively transcribed throughout development, from embryo to adult. RNA interference (RNAi)-aided knockdown of Hvmyo delayed larval development by more than 2 days, reduced larval body size, inhibited the growth of antennae, wings and legs and disturbed gut purge. Knockdown of Hvmyo impaired the larval-pupal transition. All the Hvmyo RNAi larvae arrested at the larval stage or formed misshapen pupae or adults. The deformed pupae and adults were partially wrapped with exuviae, bearing separated wings. Moreover, the expression levels of five ecdysteroidogenesis genes (Hvspo, Hvphm, Hvdib, Hvsad and Hvshd), a prothocicotropic hormone (PTTH)/Torso pathway gene (Hvtorso), two 20E receptor genes (HvEcR and HvUSP), and two 20E signalling genes (HvE93 and HvFTZ-F1) were as a result of HvMyo RNAi significantly lowered. Conversely, the expression of a JH biosynthesis gene (Hvjhamt), a JH receptor gene HvMet and a JH signalling gene HvKr-h1 was greatly enhanced. Although ingestion of 20E and Hal rescued the 20E signal, it could not alleviate larval performance and defective phenotypes. Our results suggest that Myo exerts four distinctive roles in ecdysteroidogenesis, JH production, organ growth and larva-pupa-adult transformation in H. vigintioctopunctata.
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Affiliation(s)
- Feng Chen
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests/State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Xiao-Qing Zhang
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests/State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Jian-Jian Wu
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests/State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Lin Jin
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests/State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Guo-Qing Li
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests/State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
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15
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Li J, Yin L, Bi J, Stanley D, Feng Q, Song Q. The TGF-β Receptor Gene Saxophone Influences Larval-Pupal-Adult Development in Tribolium castaneum. Molecules 2022; 27:molecules27186017. [PMID: 36144752 PMCID: PMC9505606 DOI: 10.3390/molecules27186017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/30/2022] [Accepted: 09/11/2022] [Indexed: 11/16/2022] Open
Abstract
The transforming growth factor-β (TGF-β) superfamily encodes a large group of proteins, including TGF-β isoforms, bone morphogenetic proteins and activins that act through conserved cell-surface receptors and signaling co-receptors. TGF-β signaling in insects controls physiological events, including growth, development, diapause, caste determination and metamorphosis. In this study, we used the red flour beetle, Tribolium castaneum, as a model species to investigate the role of the type I TGF-β receptor, saxophone (Sax), in mediating development. Developmental and tissue-specific expression profiles indicated Sax is constitutively expressed during development with lower expression in 19- and 20-day (6th instar) larvae. RNAi knockdown of Sax in 19-day larvae prolonged developmental duration from larvae to pupae and significantly decreased pupation and adult eclosion in a dose-dependent manner. At 50 ng dsSax/larva, Sax knockdown led to an 84.4% pupation rate and 46.3% adult emergence rate. At 100 ng and 200 ng dsSax/larva, pupation was down to 75.6% and 50%, respectively, with 0% adult emergence following treatments with both doses. These phenotypes were similar to those following knockdowns of 20-hydroxyecdysone (20E) receptor genes, ecdysone receptor (EcR) or ultraspiracle protein (USP). Expression of 20E biosynthesis genes disembodied and spookier, 20E receptor genes EcR and USP, and 20E downstream genes BrC and E75, were suppressed after the Sax knockdown. Topical application of 20E on larvae treated with dsSax partially rescued the dsSax-driven defects. We can infer that the TGF-β receptor gene Sax influences larval-pupal-adult development via 20E signaling in T. castaneum.
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Affiliation(s)
- Jingjing Li
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
| | - Letong Yin
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
| | - Jingxiu Bi
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
- Institution of Quality Standard and Testing Technology for Agro-Product, Shandong Academy of Agricultural Science, Jinan 250100, China
| | - David Stanley
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
- Biological Control of Insect Research Laboratory, United States Department of Agriculture-Agricultural Research Station (USDA/ARS), Columbia, MO 65203, USA
| | - Qili Feng
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Qisheng Song
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
- Correspondence:
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16
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Gao X, Zhang J, Wu P, Shu R, Zhang H, Qin Q, Meng Q. Conceptual framework for the insect metamorphosis from larvae to pupae by transcriptomic profiling, a case study of Helicoverpa armigera (Lepidoptera: Noctuidae). BMC Genomics 2022; 23:591. [PMID: 35963998 PMCID: PMC9375380 DOI: 10.1186/s12864-022-08807-y] [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: 04/28/2022] [Accepted: 07/31/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Insect metamorphosis from larvae to pupae is one of the most important stages of insect life history. Relatively comprehensive information related to gene transcription profiles during lepidopteran metamorphosis is required to understand the molecular mechanism underlying this important stage. We conducted transcriptional profiling of the brain and fat body of the cotton bollworm Helicoverpa armigera (Lepidoptera: Noctuidae) during its transition from last instar larva into pupa to explore the physiological processes associated with different phases of metamorphosis. RESULTS During metamorphosis, the differences in gene expression patterns and the number of differentially expressed genes in the fat body were found to be greater than those in the brain. Each stage had a specific gene expression pattern, which contributed to different physiological changes. A decrease in juvenile hormone levels at the feeding stage is associated with increased expression levels of two genes (juvenile hormone esterase, juvenile hormone epoxide hydrolase). The expression levels of neuropeptides were highly expressed at the feeding stage and the initiation of the wandering stage and less expressed at the prepupal stage and the initiation of the pupal stage. The transcription levels of many hormone (or neuropeptide) receptors were specifically increased at the initiation of the wandering stage in comparison with other stages. The expression levels of many autophagy-related genes in the fat body were found to be gradually upregulated during metamorphosis. The activation of apoptosis was probably related to enhanced expression of many key genes (Apaf1, IAP-binding motif 1 like, cathepsins, caspases). Active proliferation might be associated with enhanced expression levels in several factors (JNK pathway: jun-D; TGF-β pathway: decapentaplegic, glass bottom boat; insulin pathway: insulin-like peptides from the fat body; Wnt pathway: wntless, TCF/Pangolin). CONCLUSIONS This study revealed several vital physiological processes and molecular events of metamorphosis and provided valuable information for illustrating the process of insect metamorphosis from larvae to pupae.
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Affiliation(s)
- Xinxin Gao
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jihong Zhang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Peipei Wu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Ruihao Shu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Shanghai, China
| | - Huan Zhang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Qilian Qin
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Qian Meng
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
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17
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Du JL, Chen F, Wu JJ, Jin L, Li GQ. Smad on X is vital for larval-pupal transition in a herbivorous ladybird beetle. JOURNAL OF INSECT PHYSIOLOGY 2022; 139:104387. [PMID: 35367434 DOI: 10.1016/j.jinsphys.2022.104387] [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: 01/07/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 06/14/2023]
Abstract
Insect development is regulated by a combination of juvenile hormone (JH) and 20-hydroxyecdysone (20E). Production of both JH and 20E is regulated by transforming growth factor-β (TGFβ) signaling. TGFβ can be classified into two branches, the Activin and Bone Morphogenetic Protein (BMP) pathways. In Drosophila melanogaster, BMP signaling is critical for JH synthesis, whereas Activin signal is required to generate the large pulse of 20E necessary for entering metamorphosis. However, to which extent the roles of these signals are conserved remains unknown. Here we studied the role of an Activin component Smad on X (Smox) in post-embryonic development in a defoliating ladybird Henosepilachna vigintioctopunctata. RNA interference (RNAi)-aided knockdown of Hvsmox inhibited larval growth, and impaired larval development. All Hvmyo RNAi larvae arrested at the fourth-instar larval stage. Moreover, knockdown of Hvsmox delayed gut and Malpighian tubules remodeling. Furthermore, the expression of a JH biosynthesis gene (Hvjhamt), a JH receptor gene HvMet and a JH response gene HvKr-h1 was greatly enhanced. Conversely, the expression levels of an ecdysteroidogenesis gene (Hvspo), a 20E receptor gene (HvEcR) and six 20E response genes (HvBrC, HvE74, HvE75, HvE93, HvHR3 and HvHR4) were significantly lowered. Knockdown of HvMet partially restored the negative phenotypes in the Hvsmox RNAi beetles. Our results suggest that Smox exerts regulative roles in JH production, ecdysteroidogenesis and organ remodeling, thus contributing to modulate the larva-pupa-adult transformation in H. vigintioctopunctata.
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Affiliation(s)
- Jun-Li Du
- College of Agriculture, Anhui Science and Technology University, Fengyang, Anhui 233100, China; Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests/ State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Feng Chen
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests/ State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Jian-Jian Wu
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests/ State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Lin Jin
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests/ State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Guo-Qing Li
- Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests/ State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
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18
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Chinmo is the larval member of the molecular trinity that directs Drosophila metamorphosis. Proc Natl Acad Sci U S A 2022; 119:e2201071119. [PMID: 35377802 PMCID: PMC9169713 DOI: 10.1073/pnas.2201071119] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The genome of insects with complete metamorphosis contains the instructions for making three distinct body forms, that of the larva, of the pupa, and of the adult. However, the molecular mechanisms by which each gene set is called forth and stably expressed are poorly understood. A half century ago, it was proposed that there was a set of three master genes that inhibited each other’s expression and enabled the expression of genes for each respective stage. We show that the transcription factor chinmo is essential for maintaining the larval stage in Drosophila, and with two other regulatory genes, broad and E93, makes up the trinity of mutually repressive master genes that underlie insect metamorphosis. The molecular control of insect metamorphosis from larva to pupa to adult has long been a mystery. The Broad and E93 transcription factors, which can modify chromatin domains, are known to direct the production of the pupa and the adult, respectively. We now show that chinmo, a gene related to broad, is essential for the repression of these metamorphic genes. Chinmo is strongly expressed during the formation and growth of the larva and its removal results in the precocious expression of broad and E93 in the first stage larva, causing a shift from larval to premetamorphic functions. This trinity of Chinmo, Broad, and E93 regulatory factors is mutually inhibitory. The interaction of this network with regulatory hormones likely ensures the orderly progression through insect metamorphosis.
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19
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Suzuki Y, Toh L. Constraints and Opportunities for the Evolution of Metamorphic Organisms in a Changing Climate. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.734031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We argue that developmental hormones facilitate the evolution of novel phenotypic innovations and timing of life history events by genetic accommodation. Within an individual’s life cycle, metamorphic hormones respond readily to environmental conditions and alter adult phenotypes. Across generations, the many effects of hormones can bias and at times constrain the evolution of traits during metamorphosis; yet, hormonal systems can overcome constraints through shifts in timing of, and acquisition of tissue specific responses to, endocrine regulation. Because of these actions of hormones, metamorphic hormones can shape the evolution of metamorphic organisms. We present a model called a developmental goblet, which provides a visual representation of how metamorphic organisms might evolve. In addition, because developmental hormones often respond to environmental changes, we discuss how endocrine regulation of postembryonic development may impact how organisms evolve in response to climate change. Thus, we propose that developmental hormones may provide a mechanistic link between climate change and organismal adaptation.
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20
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Chafino S, Martín D, Franch-Marro X. Activation of EGFR signaling by Tc-Vein and Tc-Spitz regulates the metamorphic transition in the red flour beetle Tribolium castaneum. Sci Rep 2021; 11:18807. [PMID: 34552169 PMCID: PMC8458297 DOI: 10.1038/s41598-021-98334-9] [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: 05/12/2021] [Accepted: 08/25/2021] [Indexed: 02/08/2023] Open
Abstract
Animal development relies on a sequence of specific stages that allow the formation of adult structures with a determined size. In general, juvenile stages are dedicated mainly to growth, whereas last stages are devoted predominantly to the maturation of adult structures. In holometabolous insects, metamorphosis marks the end of the growth period as the animals stops feeding and initiate the final differentiation of the tissues. This transition is controlled by the steroid hormone ecdysone produced in the prothoracic gland. In Drosophila melanogaster different signals have been shown to regulate the production of ecdysone, such as PTTH/Torso, TGFß and Egfr signaling. However, to which extent the roles of these signals are conserved remains unknown. Here, we study the role of Egfr signaling in post-embryonic development of the basal holometabolous beetle Tribolium castaneum. We show that Tc-Egfr and Tc-pointed are required to induced a proper larval-pupal transition through the control of the expression of ecdysone biosynthetic genes. Furthermore, we identified an additional Tc-Egfr ligand in the Tribolium genome, the neuregulin-like protein Tc-Vein (Tc-Vn), which contributes to induce larval-pupal transition together with Tc-Spitz (Tc-Spi). Interestingly, we found that in addition to the redundant role in the control of pupa formation, each ligand possesses different functions in organ morphogenesis. Whereas Tc-Spi acts as the main ligand in urogomphi and gin traps, Tc-Vn is required in wings and elytra. Altogether, our findings show that in Tribolium, post-embryonic Tc-Egfr signaling activation depends on the presence of two ligands and that its role in metamorphic transition is conserved in holometabolous insects.
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Affiliation(s)
- Sílvia Chafino
- grid.507636.10000 0004 0424 5398Institute of Evolutionary Biology (IBE, CSIC-Universitat Pompeu Fabra), Passeig de la Barceloneta 37, 08003 Barcelona, Catalonia Spain
| | - David Martín
- grid.507636.10000 0004 0424 5398Institute of Evolutionary Biology (IBE, CSIC-Universitat Pompeu Fabra), Passeig de la Barceloneta 37, 08003 Barcelona, Catalonia Spain
| | - Xavier Franch-Marro
- grid.507636.10000 0004 0424 5398Institute of Evolutionary Biology (IBE, CSIC-Universitat Pompeu Fabra), Passeig de la Barceloneta 37, 08003 Barcelona, Catalonia Spain
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21
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Martín D, Chafino S, Franch-Marro X. How stage identity is established in insects: the role of the Metamorphic Gene Network. CURRENT OPINION IN INSECT SCIENCE 2021; 43:29-38. [PMID: 33075581 DOI: 10.1016/j.cois.2020.10.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/07/2020] [Accepted: 10/07/2020] [Indexed: 06/11/2023]
Abstract
Proper formation of adult insects requires the integration of spatial and temporal regulatory axes. Whereas spatial information confers identity to each tissue, organ and appendage, temporal information specifies at which stage of development the animal is. Regardless of the type of post-embryonic development, either hemimetabolous or holometabolous, temporal specificity is achieved through interactions between the temporal identity genes Kr-h1, E93 and Br-C, whose sequential expression is controlled by the two major developmental hormones, 20-hydroxyecdysone and Juvenile hormone. Given the intimate regulatory connection between these three factors to specify life stage identity, we dubbed the regulatory axis that comprises these genes as the Metamorphic Gene Network (MGN). In this review, we survey the molecular mechanisms underlying the control by the MGN of stage identity and progression in hemimetabolous and holometabolous insects.
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Affiliation(s)
- David Martín
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
| | - Silvia Chafino
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Xavier Franch-Marro
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
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22
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Malita A, Rewitz K. Interorgan communication in the control of metamorphosis. CURRENT OPINION IN INSECT SCIENCE 2021; 43:54-62. [PMID: 33214126 DOI: 10.1016/j.cois.2020.10.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/12/2020] [Accepted: 10/14/2020] [Indexed: 06/11/2023]
Abstract
Steroid hormones control major developmental transitions such as metamorphosis in insects and puberty in mammals. The juvenile must attain a sufficient size before it begins maturation in order to give rise to a properly sized and reproductively fit adult. Studies in the insect Drosophila have begun to reveal a remarkable example of the complex interplay between different organs and the neuroendocrine system that controls the production of the steroid ecdysone, which triggers metamorphosis. This review discusses the inter-organ signals mediating this crosstalk, which allows the neuroendocrine system to assess nutrient availability and growth status of internal organs, ensuring that maturation is initiated at the appropriate time. We discuss how the neuroendocrine system integrates signals from different tissues to coordinate growth and maturation. These studies are still unraveling the organ-to-organ signaling networks that control the timing of metamorphosis, defining important principles underlying the logic of growth and maturation coordination in animals.
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Affiliation(s)
- Alina Malita
- Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Kim Rewitz
- Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark.
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