University of Oulu

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).

Suppression of Gq and PLC gene expression has a small effect on quantum bumps in vivo in Periplaneta americana

Saved in:
Author: Ignatova, Irina I.1; French, Andrew S.2; Torkkeli, Päivi H.2;
Organizations: 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
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.8 MB)
Persistent link:
Language: English
Published: Springer Nature, 2020
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.

see all

Series: Journal of comparative physiology. A
ISSN: 0340-7594
ISSN-E: 1432-1351
ISSN-L: 0340-7594
Volume: 206
Issue: 4
Pages: 597 - 610
DOI: 10.1007/s00359-020-01417-7
Type of Publication: A1 Journal article – refereed
Field of Science: 1184 Genetics, developmental biology, physiology
Funding: 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.
Copyright information: © The Author(s) 2020. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit