scholarly journals E93-depleted adult insects preserve the prothoracic gland and molt again

Development ◽  
2020 ◽  
Vol 147 (22) ◽  
pp. dev190066
Author(s):  
Orathai Kamsoi ◽  
Xavier Belles
Keyword(s):  
Transcription Factor ◽  
Crucial Role ◽  
Middle Devonian ◽  
Adult Stage ◽  
Epidermal Cells ◽  
Prothoracic Gland ◽  
Molting Hormone ◽  
Nymphal Instar ◽  
Insect Metamorphosis ◽  
Final Molt

ABSTRACTInsect metamorphosis originated around the middle Devonian, associated with the innovation of the final molt; this occurs after histolysis of the prothoracic gland (PG; which produces the molting hormone) in the first days of adulthood. We previously hypothesized that transcription factor E93 is crucial in the emergence of metamorphosis, because it triggers metamorphosis in extant insects. This work on the cockroach Blattella germanica reveals that E93 also plays a crucial role in the histolysis of PG, which fits the above hypothesis. Previous studies have shown that the transcription factor FTZ-F1 is essential for PG histolysis. We have found that FTZ-F1 depletion towards the end of the final nymphal instar downregulates the expression of E93, whereas E93-depleted nymphs molt to adults that retain a functional PG. Interestingly, these adults are able to molt again, which is exceptional in insects. The study of insects able to molt again in the adult stage may reveal clues about how nymphal epidermal cells definitively become adult cells, and whether it is possible to reverse this process.

scholarly journals E93-depleted adult insects preserve the prothoracic gland and molt again

2020 ◽  
Author(s):  
Orathai Kamsoi ◽  
Xavier Belles
Keyword(s):  
Transcription Factor ◽  
Crucial Role ◽  
Middle Devonian ◽  
Adult Stage ◽  
Prothoracic Gland ◽  
Molting Hormone ◽  
Nymphal Instar ◽  
Insect Metamorphosis ◽  
Summary Statement ◽  
Final Molt

ABSTRACTInsect metamorphosis originated around the middle Devonian, associated with the innovation of the final molt; this occurs after the histolysis of the prothoracic gland (PG; which produces the molting hormone) in the first days of adulthood. We previously hypothesized that transcription factor E93 was crucial in the emergence of metamorphosis, since it triggers metamorphosis in extant insects. This work on the cockroach Blattella germanica reveals that E93 also plays a crucial role in the histolysis of PG, which fits the above hypothesis. Previous studies have shown that the transcription factor FTZ-F1 is essential for PG histolysis. We have found that FTZ-F1 depletion, towards the end of the final nymphal instar, downregulates the expression of E93, while E93-depleted nymphs molt to adults that retain a functional PG. Interestingly, these adults are able to molt again, which is exceptional in insects. The study of insects able to molt again in the adult stage may reveal clues as to how nymphal epidermal cells definitively become adult cells, and if it is possible to revert this process.Summary statementThe prothoracic gland disintegrates after insect metamorphosis. It was believed that the factor FTZ-F1 determines this disintegration. This work reveals that FTZ-F1 action is mediated by the factor E93.

scholarly journals The innovation of the final moult and the origin of insect metamorphosis

2019 ◽  
Vol 374 (1783) ◽  
pp. 20180415 ◽  
Author(s):  
Xavier Belles
Keyword(s):  
Common Ancestor ◽  
Adult Stage ◽  
Postembryonic Development ◽  
Prothoracic Gland ◽  
Last Common Ancestor ◽  
Early Devonian ◽  
Final Moult ◽  
Insect Metamorphosis ◽  
Complete Metamorphosis

The three modes of insect postembryonic development are ametaboly, hemimetaboly and holometaboly, the latter being considered the only significant metamorphosis mode. However, the emergence of hemimetaboly, with the genuine innovation of the final moult, represents the origin of insect metamorphosis and a necessary step in the evolution of holometaboly. Hemimetaboly derives from ametaboly and might have appeared as a consequence of wing emergence in Pterygota, in the early Devonian. In extant insects, the final moult is mainly achieved through the degeneration of the prothoracic gland (PG), after the formation of the winged and reproductively competent adult stage. Metamorphosis, including the formation of the mature wings and the degeneration of the PG, is regulated by the MEKRE93 pathway, through which juvenile hormone precludes the adult morphogenesis by repressing the expression of transcription factor E93, which triggers this change. The MEKRE93 pathway appears conserved in extant metamorphosing insects, which suggest that this pathway was operative in the Pterygota last common ancestor. We propose that the final moult, and the consequent hemimetabolan metamorphosis, is a monophyletic innovation and that the role of E93 as a promoter of wing formation and the degeneration of the PG was mechanistically crucial for their emergence. This article is part of the theme issue ‘The evolution of complete metamorphosis’.

scholarly journals MiR-2 family regulates insect metamorphosis by controlling the juvenile hormone signaling pathway

2015 ◽  
Vol 112 (12) ◽  
pp. 3740-3745 ◽  
Author(s):  
Jesus Lozano ◽  
Raúl Montañez ◽  
Xavier Belles
Keyword(s):  
Transcription Factor ◽  
Juvenile Hormone ◽  
Binding Site ◽  
Signaling Pathway ◽  
Blattella Germanica ◽  
Mrna Levels ◽  
Hormone Signaling ◽  
Nymphal Instar ◽  
Insect Metamorphosis ◽  
Krüppel Homolog 1

In 2009 we reported that depletion of Dicer-1, the enzyme that catalyzes the final step of miRNA biosynthesis, prevents metamorphosis inBlattella germanica. However, the precise regulatory roles of miRNAs in the process have remained elusive. In the present work, we have observed that Dicer-1 depletion results in an increase of mRNA levels of Krüppel homolog 1 (Kr-h1), a juvenile hormone-dependent transcription factor that represses metamorphosis, and that depletion of Kr-h1 expression in Dicer-1 knockdown individuals rescues metamorphosis. We have also found that the 3′UTR of Kr-h1 mRNA contains a functional binding site for miR-2 family miRNAs (for miR-2, miR-13a, and miR-13b). These data suggest that metamorphosis impairment caused by Dicer-1 and miRNA depletion is due to a deregulation of Kr-h1 expression and that this deregulation is derived from a deficiency of miR-2 miRNAs. We corroborated this by treating the last nymphal instar ofB. germanicawith an miR-2 inhibitor, which impaired metamorphosis, and by treating Dicer-1-depleted individuals with an miR-2 mimic to allow nymphal-to-adult metamorphosis to proceed. Taken together, the data indicate that miR-2 miRNAs scavenge Kr-h1 transcripts when the transition from nymph to adult should be taking place, thus crucially contributing to the correct culmination of metamorphosis.

scholarly journals SOG1 transcription factor promotes the onset of endoreduplication under salinity stress in Arabidopsis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kalyan Mahapatra ◽  
Sujit Roy
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Death ◽  
Transcription Factor ◽  
Programmed Cell Death ◽  
Salinity Stress ◽  
Crucial Role ◽  
Genome Stability ◽  
Cell Cycle Checkpoint ◽  
Cell Cycle Regulators

AbstractAs like in mammalian system, the DNA damage responsive cell cycle checkpoint functions play crucial role for maintenance of genome stability in plants through repairing of damages in DNA and induction of programmed cell death or endoreduplication by extensive regulation of progression of cell cycle. ATM and ATR (ATAXIA-TELANGIECTASIA-MUTATED and -RAD3-RELATED) function as sensor kinases and play key role in the transmission of DNA damage signals to the downstream components of cell cycle regulatory network. The plant-specific NAC domain family transcription factor SOG1 (SUPPRESSOR OF GAMMA RESPONSE 1) plays crucial role in transducing signals from both ATM and ATR in presence of double strand breaks (DSBs) in the genome and found to play crucial role in the regulation of key genes involved in cell cycle progression, DNA damage repair, endoreduplication and programmed cell death. Here we report that Arabidopsis exposed to high salinity shows generation of oxidative stress induced DSBs along with the concomitant induction of endoreduplication, displaying increased cell size and DNA ploidy level without any change in chromosome number. These responses were significantly prominent in SOG1 overexpression line than wild-type Arabidopsis, while sog1 mutant lines showed much compromised induction of endoreduplication under salinity stress. We have found that both ATM-SOG1 and ATR-SOG1 pathways are involved in the salinity mediated induction of endoreduplication. SOG1was found to promote G2-M phase arrest in Arabidopsis under salinity stress by downregulating the expression of the key cell cycle regulators, including CDKB1;1, CDKB2;1, and CYCB1;1, while upregulating the expression of WEE1 kinase, CCS52A and E2Fa, which act as important regulators for induction of endoreduplication. Our results suggest that Arabidopsis undergoes endoreduplicative cycle in response to salinity induced DSBs, showcasing an adaptive response in plants under salinity stress.

scholarly journals A crucial role for the homeodomain transcription factor Hhex in lymphopoiesis

Blood ◽  
2015 ◽  
Vol 125 (5) ◽  
pp. 803-814 ◽  
Author(s):  
Jacob T. Jackson ◽  
Chayanica Nasa ◽  
Wei Shi ◽  
Nicholas D. Huntington ◽  
Clifford W. Bogue ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Crucial Role ◽  
Homeodomain Transcription Factor ◽  
Key Points

Key Points Hhex regulates development of diverse lymphoid lineages. Hhex regulates cycling of lymphoid precursors.

scholarly journals Redistribution of Transcription Factor AP-2α in Differentiating Cultured Human Epidermal Cells

2001 ◽  
Vol 117 (4) ◽  
pp. 864-870 ◽  
Author(s):  
Olga M. Mazina ◽  
Marjorie A. Phillips ◽  
Trevor Williams ◽  
Carol A. Vines ◽  
Gary N. Cherr ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Epidermal Cells ◽  
Human Epidermal Cells

scholarly journals A crucial role for the ubiquitously expressed transcription factor Sp1 at early stages of hematopoietic specification

Development ◽  
2014 ◽  
Vol 141 (12) ◽  
pp. 2391-2401 ◽  
Author(s):  
J. Gilmour ◽  
S. A. Assi ◽  
U. Jaegle ◽  
D. Kulu ◽  
H. van de Werken ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Crucial Role ◽  
Early Stages ◽  
Transcription Factor Sp1

TRANSCRIPTION FACTOR Bmsage PLAYS A CRUCIAL ROLE IN SILK GLAND GENERATION IN SILKWORM,Bombyx mori

2015 ◽  
Vol 90 (2) ◽  
pp. 59-69 ◽  
Author(s):  
Hu-hu Xin ◽  
Deng-pan Zhang ◽  
Rui-ting Chen ◽  
Zi-zheng Cai ◽  
Yan Lu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Bombyx Mori ◽  
Crucial Role ◽  
Silk Gland ◽  
Silkworm Bombyx Mori

scholarly journals Drosophila larval epidermal cells only exhibit epidermal aging when they persist to the adult stage

2020 ◽  
Author(s):  
Yan Wang ◽  
Sirisha Burra ◽  
Michael J. Galko
Keyword(s):  
Larval Stage ◽  
Cell Membranes ◽  
Adult Stage ◽  
Body Plan ◽  
Epidermal Cells ◽  
The Body ◽  
Multinucleate Cells ◽  
Aging Program ◽  
Summary Statement ◽  
Complete Transformation

AbstractHolometabolous insects undergo a complete transformation of the body plan from the larval to the adult stage. In Drosophila, this transformation includes replacement of larval epidermal cells (LECs) by adult epidermal cells (AECs). AECs in Drosophila undergo a rapid and stereotyped aging program where they lose both cell membranes and nuclei. Whether LEC’s are capable of undergoing aging in a manner similar to AECs remains unknown. Here, we address this question in two ways. First, we looked for hallmarks of epidermal aging in larvae that have a greatly extended third instar and/or carry mutations that would cause premature epidermal aging at the adult stage. Such larvae, irrespective of genotype, did not show any of the signs of epidermal aging observed in the adult. Second, we developed a procedure to effect a heterochronic persistence of LECs into the adult epidermal sheet. LECs embedded within the adult epidermal sheet undergo clear signs of epidermal aging; they form multinucleate cells with each other and with the surrounding AECs on the same schedule as the AECs themselves. Our data reveals that epidermal aging in holometabolous Drosophila is a stage-specific phenomenon and that the capacity of LECs to respond to aging signals does exist.Summary StatementWe show that Drosophila larval epidermal cells do not age at the larval stage. They do, however, exhibit signs of aging if they persist into the adult.

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