Upregulation of E93 gene expression acts as the trigger for metamorphosis independently of the threshold size in the beetle tribolium castaneum

Body size in holometabolous insects is determined by the size at which the juvenile larva undergoes metamorphosis to the pupal stage. To undergo larva-pupa transition, larva must reach a critical developmental checkpoint, the threshold size (TS); however, the molecular mechanisms through which the T...

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Detalles Bibliográficos
Autores: Chafino Aixa, Silvia, 1991-, Ureña, Enric, Casanova, Jordi, Casacuberta Suñer, Elena, 1972-, Franch i Marro, Xavier, Martín, David
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2019
País:España
Institución:Universitat Pompeu Fabra
Repositorio:Repositorio Digital de la UPF
OAI Identifier:oai:repositori.upf.edu:10230/44808
Acceso en línea:http://hdl.handle.net/10230/44808
http://dx.doi.org/10.1016/j.celrep.2019.03.094
Access Level:acceso abierto
Palabra clave:E93
Kr-h1
Tribolium castaneum
Broad-complex
Ecdysone
Growth control
Holometaboly
Insect metamorphosis
Juvenile hormone
Threshold size
Descripción
Sumario:Body size in holometabolous insects is determined by the size at which the juvenile larva undergoes metamorphosis to the pupal stage. To undergo larva-pupa transition, larva must reach a critical developmental checkpoint, the threshold size (TS); however, the molecular mechanisms through which the TS cues this transition remain to be fully characterized. Here, we use the flour beetle Tribolium castaneum to characterize the molecular mechanisms underlying entry into metamorphosis. We found that T. castaneum reaches a TS at the beginning of the last larval instar, which is associated with the downregulation of TcKr-h1 and the upregulation of TcE93 and TcBr-C. Unexpectedly, we found that while there is an association between TS and TcE93 upregulation, it is the latter that constitutes the molecular trigger for metamorphosis initiation. In light of our results, we evaluate the interactions that control the larva-pupa transition and suggest alternative models.