Work Package 5 (ESR 6)

Diapause and neuropeptides

General details

ItalyLocation
University of Padova, IT

Supervisors
Prof. R. Costa

ESR 6
XXX

Other partners involved
University of Leicester (UK)

Secondments

University of Leicester for 4 months in year 2, and 2 months in year 3 to train on natural diapausing paradigms

Objectives

  • Analyse diapause in flies with defects in development of visual photoreception or neurotransmission
  • Perform a systematic genetic analysis of the neuroendocrine axis of Drosophila melanogaster to identify the key molecules and organs involved in the diapause process

Methods

  • Define role in diapause of short neuropeptide F precursor (sNPF) produced by the M-neurons by month 18
  • Investigate on synaptic connections between M-neurons and neurons of the pars lateralis by month 26
  • Define the role in diapause of the Median Neurosecretory Cells (MNCs) and Corpora Allata (CA), focussing in particular on Insulin Like Proteins (dILPs) by month 30
  • Test MNCs and Insulin-like signalling (IIS) self-regulation by an autocrine negative feedback by month 36

Description

Genetic analysis of neuroendocrine axis and diapause in Drosophila
A systematic analysis of the Drosophila neuroendocrine axis in relation to the key organs and molecules involved in diapause will be performed. The M (morning) clock cells produce two neurocrines, short neuropeptide F precursor (sNPF) and pigment dispersing factor (PDF), and we recently observed that sNPF downregulation dramatically increases diapause incidence. M cells send axonal projections to neurosecretory cells of the pars lateralis (i.e., corazonin neurons) which in turn show synapsis with the neurohaemal complex. Hormones affecting the ovarian axis and produced by the neurohaemal complex are probably regulated by insulin producing cells (IPCs). Thus downstream pathway to diapause from the M cells is possible. We will study how light, the upstream signal, might control sNPF signalling to produce photoperiodic diapause, so we will analyse a number of mutants with defects in the development of visual photoreception, defects in neurotransmission, or flies in which a Gal4/UAS misregulation of photoreception will be induced. Finally, we will investigate the temperature permissiveness of diapause photoperiodism. To this end we intend to analyse in detail the Insulin signalling (IIS) which controls ovarian development. Our hypothesis is that IIS could represent a “gate” for developmental timing signals, the inhibition of which could close the gate. We will therefore investigate pathways which putatively mediate a downregulation of IIS at diapause inducing temperatures. For WP1 and WP2, Helfrich-Forster, Rouyer, Pyza and Stanewsky will play supporting roles in deciphering light and temperature signals for diapause. Our results will naturally complement those from the comparative studies of diapause in Nasonia and Pyrrhocoris so the PIs of WP3 and WP5 will be co-advisors.

Results and milestones

1) Month 8 Project plan & personal development plan for individual training requirements
2) Month 14 Report of detailed research plans
3) Month 26 Report of experimental results and plans for publication
4) Month 36 At least one publication drafted

Synergies, Risks & Exploitation

University of Padova benefits from using the Leicester natural diapause paradigm and the Wuerzburg expertise in gene expression and ICC. Homologous sequences of Drosophila’s diapause-relevant genes will be used by our SME partners to improve their existing insect control strategies.

See more Work Packages in Research Area B