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FoxO inhibits juvenile hormone biosynthesis and vitellogenin production in the German cockroach

Songül Süren-Castillo1, Marc Abrisqueta, José L Maestro

  • 1Institut de Biologia Evolutiva (CSIC-UPF), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.

Insect Biochemistry and Molecular Biology
|April 11, 2012
PubMed

Insights

Forkhead-box O (FoxO) in cockroaches inhibits reproduction during starvation. Silencing FoxO boosted juvenile hormone and vitellogenin, revealing its key role in nutrient-dependent reproductive control.

Area of Science:

  • Insect reproductive endocrinology
  • Molecular mechanisms of nutrient sensing
  • FoxO transcription factor function

Background:

  • The Insulin Receptor/Phosphatidylinositol 3-kinase (InR/PI3K) pathway regulates cellular processes, with Forkhead-box O (FoxO) as its primary transcriptional effector.
  • Nutrient restriction inactivates the InR/PI3K pathway, leading to FoxO nuclear translocation and transcriptional activity.
  • In starved female cockroaches (Blattella germanica), reproductive functions like juvenile hormone and vitellogenin synthesis are arrested.

Purpose of the Study:

  • To investigate the role of FoxO in mediating nutritional signals to reproductive events in Blattella germanica.
  • To determine if FoxO expression is regulated by nutritional status.
  • To elucidate the impact of FoxO on juvenile hormone biosynthesis and vitellogenin production under starvation.

Main Methods:

  • Cloning of FoxO cDNA from Blattella germanica (BgFoxO).
  • Systemic RNA interference (RNAi) to knockdown BgFoxO expression in starved females.
  • Quantification of juvenile hormone biosynthesis and related gene expression in corpora allata.
  • Measurement of vitellogenin mRNA levels in fat body and vitellogenin protein in hemolymph.

Main Results:

  • BgFoxO expression was not found to be nutritionally regulated.
  • BgFoxO knockdown in starved females resulted in increased juvenile hormone biosynthesis.
  • BgFoxO knockdown led to significantly elevated vitellogenin mRNA levels and protein in the hemolymph.

Conclusions:

  • BgFoxO functions as an inhibitor of juvenile hormone biosynthesis.
  • BgFoxO plays an inhibitory role in vitellogenin production.
  • FoxO is crucial for arresting reproductive processes during nutrient shortage in Blattella germanica.

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