Neurobiology of the Platynereis ciliated larva
University of Washington’s Friday Harbor Labs
Recorded talk Aug 8, 2024
Platynereis dumerilii
- breeding culture
- microinjection, transgenesis
- neuron-specific promoters and antibodies
- knock-out lines
- neuronal connectome
- neuronal activity imaging 😎
Simple direction-sensing eyespots in the trochophore
trochophora larva
Direct sensory-motor coupling of eyes to cilia
pigment cup of eye
photoreceptor cell
The eyespots mediate phototaxis
Helical swimming, sensing and turning are tightly linked
Whole-body volume EM of an entire Platynereis larva
Synaptic connectome
Annotation of all cell types
Information flow from sensors to effectors
Sensory cell synapses
Sensory cells in the head
Mushroom bodies
The mechanosensory girdle
Neural circuit of the visual eyes
Simple eyespots are widespread in marine larvae
In quest of the origin of eyes
UV response in Platynereis larvae
UV response in Platynereis larvae
Brain ciliary photoreceptors with ramified cilia
Reduced ciliary compartment in c-opsin1 mutants
UV avoidance is dependent on c-opsin1
Circuitry of ciliary photoreceptors
Circuitry of ciliary photoreceptors
Strong cPRC activation after UV exposure
UV response is c-opsin1-dependent
Nitric-oxide synthase in postsynaptic interneurons
HCR
Transgenic labelling
immunostaining
NO is produced in the neuropil after UV stimulation
NOS mutants have altered cPRC response
NOS mutants have altered INRGW response
Ciliary response to UV in wt and NOS mutants
ciliary beat frequency
Swimming speed
NOS mutants show defective UV avoidance
NO signal is short-range
NOS protein in the INNOS dendritic compartment
Two unusual guanylyl cyclases in the cPRCs
NIT-GC1 RNA
NIT-GC1 protein
NIT-GC2 RNA
NIT-GC2 protein
Two unusual guanylyl cyclases in the cPRCs
NIT-GC1 producs cGMP upon NO addition
NIT-GC1 mediates NO-feedback
anti-NIT-GC1 immuno
NIT-GC2 mediates phototransduction
anti-NIT-GC2 immuno
Mathematical modelling of the circuit
Model fitting
wild type
NOS-11
NOS-23
NIT-GC2 mo.
Synaptic+chemical connectomes -> circuit dynamics and function
Pressure response in Platynereis larvae
Ciliary photoreceptor cells sense Δ pressure
Microscopy pressure chamber 
Calcium imaging 
Photoreceptor responses to pressure are graded
Pressure increases ciliary beating through serotonergic cells
Acknowledgements
- Emelie Brodrick
- Cyrielle Kaltenrieder
- Réza Shahidi
- Milena Marinkovic
- Daniel Thiel
- Sanja Jasek
- Cameron Hird
- Rebecca Turner
- Luis A. Bezares-Calderón
- Kei Jokura
- Luis Yanez Guerra
- Alexandra Kerbl
Former lab members
- Albina Asadulina
- James Beard
- Markus Conzelmann
- Nadine Randel
- Philipp Bauknecht
- Martin Gühmann
- Cristina Pineiro-Lopez
- Nobuo Ueda
- Aurora Panzera
- Csaba Verasztó
- Elizabeth Williams