Sensory regulation of neuroligins and neurexin I in the honeybee brain.
BACKGROUND
Neurexins and neuroligins, which have recently been associated with neurological disorders such as autism in humans, are highly conserved adhesive proteins found on synaptic membranes of neurons. These binding partners produce a trans-synaptic bridge that facilitates maturation and specification of synapses. It is believed that there exists an optimal spatio-temporal code of neurexin and neuroligin interactions that guide synapse formation in the postnatal developing brain. Therefore, we investigated whether neuroligins and neurexin are differentially regulated by sensory input using a behavioural model system with an advanced capacity for sensory processing, learning and memory, the honeybee.


RESULTS
Whole brain expression levels of neuroligin 1-5 (NLG1-5) and neurexin I (NrxI) were estimated by qRT-PCR analysis in three different behavioural paradigms: sensory deprivation, associative scent learning, and lateralised sensory input. Sensory deprived bees had a lower level of NLG1 expression, but a generally increased level of NLG2-5 and NrxI expression compared to hive bees. Bees that had undergone associative scent training had significantly increased levels of NrxI, NLG1 and NLG3 expression compared to untrained control bees. Bees that had lateralised sensory input after antennal amputation showed a specific increase in NLG1 expression compared to control bees, which only happened over time.


CONCLUSIONS
Our results suggest that (1) there is a lack of synaptic pruning during sensory deprivation; (2) NLG1 expression increases with sensory stimulation; (3) concomitant changes in gene expression suggests NrxI interacts with all neuroligins; (4) there is evidence for synaptic compensation after lateralised injury.
Biswas
Sunita
S
Queensland Brain Institute, The University of Queensland, St Lucia, Queensland, Australia.
Reinhard
Judith
J
Oakeshott
John
J
Russell
Robyn
R
Srinivasan
Mandyam V
MV
Claudianos
Charles
C
D017398:Alternative Splicing; D000818:Animals; D001245:Association Learning / Q000502:physiology; D001516:Bees / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001921:Brain / Q000378:metabolism / Q000502:physiology*; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D005260:Female; D020869:Gene Expression Profiling; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D009812:Odorants; D009833:Olfactory Pathways / Q000502:physiology; D011485:Protein Binding; D012018:Reflex / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D011984:Sensory Receptor Cells / Q000502:physiology; D012903:Smell / Q000502:physiology; D013569:Synapses / Q000502:physiology*
D015816:Cell Adhesion Molecules, Neuronal; D019476:Insect Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C093438:neuroligin 1; C098003:neuroligin 2; C098004:neuroligin 3