Microarrays reveal discrete phases in juvenile hormone regulation of mosquito reproduction

Riddiford, Lynn M.

doi:10.1073/pnas.1307487110

Cited by 11 publications

(8 citation statements)

References 9 publications

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“…aegypti females, and that both directly stimulate ovaries to produce ECD, which activates yolk production and uptake by oocytes (Brown et al, 1998; Brown et al, 2008; Gulia-Nuss et al, 2011; Riddiford, 2013). Prior studies also show that ILP3 activates insulin signaling through binding to the MIR in ovaries (Brown et al, 2008; Wen et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

Ovary ecdysteroidogenic hormone functions independently of the insulin receptor in the yellow fever mosquito, Aedes aegypti

Dhara

Eum

Robertson

et al. 2013

Insect Biochemistry and Molecular Biology

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Most mosquito species must feed on the blood of a vertebrate host to produce eggs. In the yellow fever mosquito, Aedes aegypti, blood feeding triggers medial neurosecretory cells in the brain to release insulin-like peptides (ILPs) and ovary ecdysteroidogenic hormone (OEH). Theses hormones thereafter directly induce the ovaries to produce ecdysteroid hormone (ECD), which activates the synthesis of yolk proteins in the fat body for uptake by oocytes. ILP3 stimulates ECD production by binding to the mosquito insulin receptor (MIR). In contrast, little is known about the mode of action of OEH, which is a member of a neuropeptide family called neuroparsin. Here we report that OEH is the only neuroparsin family member present in the Ae. aegypti genome and that other mosquitoes also encode only one neuroparsin gene. Immunoblotting experiments suggested that the full-length form of the peptide, which we call long OEH (lOEH), is processed into short OEH (sOEH). The importance of processing, however, remained unclear because a recombinant form of lOEH (rlOEH) and synthetic sOEH exhibited very similar biological activity. A series of experiments indicated that neither rlOEH nor sOEH bound to ILP3 or the MIR. Signaling studies further showed that ILP3 activated the MIR but rlOEH did not, yet both neuropeptides activated Akt, which is a marker for insulin pathway signaling. Our results also indicated that activation of TOR signaling in the ovaries required co-stimulation by amino acids and either ILP3 or rlOEH. Overall, we conclude that OEH activates the insulin signaling pathway independently of the MIR, and that insulin and TOR signaling in the ovaries is coupled.

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Section: Discussionmentioning

confidence: 99%

Ovary ecdysteroidogenic hormone functions independently of the insulin receptor in the yellow fever mosquito, Aedes aegypti

Dhara

Eum

Robertson

et al. 2013

Insect Biochemistry and Molecular Biology

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“…The initiation of JH synthesis in pharate adult mosquito is partitioned into two temporally discrete steps: first a process of maturation during the last 6–8 hours of pupal stage prepares the CA gland to start synthesizing low amounts of JH (Rivera-Perez et al, 2014). At eclosion, a 2-fold increase in JH synthesis brings JH synthetic rates to a value of 15–20 fmol/CA/h, a threshold level required for the maximal expression of an early-posteclosion JH-dependent gene cluster (Zou et al, 2013; Riddiford, 2013). The two-step activation guarantees that a proper rise of JH synthesis concurs with adult eclosion.…”

Section: Introductionmentioning

confidence: 99%

20-hydroxyecdysone stimulation of juvenile hormone biosynthesis by the mosquito corpora allata

Areiza

Nouzová

Rivera-Pérez

et al. 2015

Insect Biochemistry and Molecular Biology

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Juvenile hormone III (JH) is synthesized by the corpora allata (CA) and plays a key role in mosquito development and reproduction. JH titer decreases in the last instar larvae allowing pupation and metamorphosis to progress. As the anti-metamorphic role of JH comes to an end, the CA of the late pupa (or pharate adult) becomes again “competent” to synthesize JH, which plays an essential role orchestrating reproductive maturation. 20-hydroxyecdysone (20E) prepares the pupae for ecdysis, and would be an ideal candidate to direct a developmental program in the CA of the pharate adult mosquito. In this study, we provide evidence that 20E acts as an age-linked hormonal signal, directing CA activation in the mosquito pupae. Stimulation of the inactive brain-corpora allata-corpora cardiaca complex (Br-CA-CC) of the early pupa (24 h before adult eclosion or −24 h) in vitro with 20E resulted in a remarkable increase in JH biosynthesis, as well as increase in the activity of juvenile hormone acid methyltransferase (JHAMT). Addition of methyl farnesoate but not farnesoic acid also stimulated JH synthesis by the Br-CA-CC of the −24 h pupae, proving that epoxidase activity is present, but not JHAMT activity. Separation of the CA-CC complex from the brain (denervation) in the −24 h pupae also activated JH synthesis. Our results suggest that an increase in 20E titer might override an inhibitory effect of the brain on JH synthesis, phenocopying denervation. All together these findings provide compelling evidence that 20E acts as a developmental signal that ensures proper reactivation of JH synthesis in the mosquito pupae.

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“…While several studies (Kayukawa et al, 2012(Kayukawa et al, , 2013Li et al, 2011;Shin et al, 2012) have focused on two specific genes-Kr-h1 and AaET-in the search for the Met-binding DNA element, the most recent efforts were directed at identifying a more unified consensus for JHRE (Riddiford, 2013). As a first step toward this goal, microarray experiments were conducted to compare RNA from female A. aegypti fat bodies before and after removal of Met expression by RNAi (Zou et al, 2013).…”

Section: Consensus Jhre For Regulation By Metmentioning

confidence: 99%

The Juvenile Hormone Receptor and Molecular Mechanisms of Juvenile Hormone Action

Dubrovsky

Bernardo

2014

Advances in Insect Physiology

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Microarrays reveal discrete phases in juvenile hormone regulation of mosquito reproduction

Cited by 11 publications

References 9 publications

Ovary ecdysteroidogenic hormone functions independently of the insulin receptor in the yellow fever mosquito, Aedes aegypti

Ovary ecdysteroidogenic hormone functions independently of the insulin receptor in the yellow fever mosquito, Aedes aegypti

20-hydroxyecdysone stimulation of juvenile hormone biosynthesis by the mosquito corpora allata

The Juvenile Hormone Receptor and Molecular Mechanisms of Juvenile Hormone Action

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