Ignatova, I.I., French, A.S., Torkkeli, P.H. et al. Suppression of Gq and PLC gene expression has a small effect on quantum bumps in vivo in Periplaneta americana. J Comp Physiol A 206, 597–610 (2020). https://doi.org/10.1007/s00359-020-01417-7
Suppression of Gq and PLC gene expression has a small effect on quantum bumps in vivo in Periplaneta americana
|Author:||Ignatova, Irina I.1; French, Andrew S.2; Torkkeli, Päivi H.2;|
1Nano and Molecular Systems Research Unit, University of Oulu, Oulu, Finland
2Department of Physiology and Biophysics, Dalhousie University, P.O. BOX 15000, Halifax, NS, B3H 4R2, Canada
|Online Access:||PDF Full Text (PDF, 2.8 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2020083164631
|Publish Date:|| 2020-08-31
Visual signal transmission by Drosophila melanogaster photoreceptors is mediated by a Gq protein that activates a phospholipase C (PLC). Mutations and deficiencies in expression of either of these proteins cause severe defects in phototransduction. Here we investigated whether these proteins are also involved in the cockroach, Periplaneta americana, phototransduction by silencing Gq α-subunit (Gqα) and phosphoinositide-specific phospholipase C (PLC) by RNA interference and observing responses to single photons (quantum bumps, QB). We found (1) non-specific decreases in membrane resistance, membrane capacitance and absolute sensitivity in the photoreceptors of both Gqα and PLC knockdowns, and (2) small changes in QB statistics. Despite significant decreases in expressions of Gq and PLC mRNA, the changes in QB properties were surprisingly modest, with mean latencies increasing by ~ 10%, and without significant decrease in their amplitudes. To better understand our results, we used a mathematical model of the phototransduction cascade. By modifying the Gq and PLC abundances, and diffusion rates for Gq, we found that QB latencies and amplitudes deteriorated noticeably only after large decreases in the protein levels, especially when Gq diffusion was slow. Also, reduction in Gq but not PLC lowered quantum efficiency. These results suggest that expression of the proteins may be redundant.
Journal of comparative physiology. A
|Pages:||597 - 610|
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
1184 Genetics, developmental biology, physiology
The work was supported by Natural Sciences and Engineering Research Council of Canada (NSERC) Grants RGPIN/05565 (to P. H. Torkkeli) and RGPIN/03712 (to A. S. French). Open access funding provided by University of Oulu including Oulu University Hospital.
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