Bax-inhibitor-1 loss of function phenotypes are suppressed by Buffy in Drosophila
- Published
- Accepted
- Subject Areas
- Cell Biology, Genetics, Neuroscience
- Keywords
- Bax Inhibitor-1, Buffy, Drosophila melanogaster, Model of Parkinson disease, Alpha-synuclein
- Copyright
- © 2016 M'Angale et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2016. Bax-inhibitor-1 loss of function phenotypes are suppressed by Buffy in Drosophila. PeerJ Preprints 4:e2548v1 https://doi.org/10.7287/peerj.preprints.2548v1
Abstract
Background. Bax Inhibitor-1 (BI-1), an integral transmembrane protein, acts as a suppressor of Bax-induced apoptosis through regulation of endoplasmic reticulum (ER) stress-induced cell death. The gene is highly conserved being found in a diverse range of organisms that include yeast, Arabidopsis, Drosophila, mouse and humans. BI-1 is implicated in the regulation of calcium levels, reactive oxygen species, apoptosis, autophagy and ER stress signalling pathways. We inhibited the cytoprotective BI-1 in the dopa decarboxylase (Ddc) expressing neurons and in the developing eye of Drosophila melanogaster to investigate its neuroprotective functions. Methods. We assessed the longevity and locomotor ability of flies in response to altered BI-1 expression in the Ddc-Gal4-expressing neurons where we exploited two RNAi transgenic fly lines. A control that expressed the benign lacZ responding transgene was used to compare against the RNAi transgenic flies. In addition, we compared the effect of the loss of BI-1 expression in the developing eye, through biometric analysis of the number of ommatidia and extent of disruption of the ommatidial arrays. Finally, Buffy and α-synuclein were co-expressed to evaluate the potential for interactions. Results. The inhibition of BI-1 in these neurons resulted in a shortened lifespan and precocious loss of locomotor ability. The co-expression of Buffy, the sole anti-apoptotic Bcl-2 homologue in Drosophila, with BI-1-RNAi resulted in suppression of the reduced lifespan and impaired climbing ability. Expression of human α-synuclein in Drosophila dopaminergic neurons results in age-dependent loss in climbing ability. We exploited this neurotoxic system to investigate possible BI-1 neuroprotective function. The co-expression of α-synuclein with BI-1-RNAi results in decreased survival coupled with an impaired climbing ability. In supportive experiments, we employed the neuron-rich Drosophila compound eye to investigate subtle phenotypes that result from altered gene expression. The inhibition of BI-1 in the Drosophila developing eye under the direction of the GMR-Gal4 transgene results in reduced ommatidia number and increased disruption of the ommatidial array. Similarly, the co-expression of BI-1-RNAi with Buffy results in the suppression of the eye phenotypes. The expression of α-synuclein along with the inhibition of BI-1 results in reduction of ommatidia number and increased disruption of the ommatidial array. Conclusions. Inhibition of BI-1 in the dopaminergic neurons of Drosophila results in a shortened lifespan and premature loss in climbing ability, phenotypes that appear to be strongly associated with models of Parkinson disease in Drosophila. These are suppressed upon overexpression of Buffy and worsened by co-expression with α-synuclein. This suggests that BI-1 acts in neuroprotection and that its inhibition can be counteracted by the overexpression of the pro-survival Bcl-2 homologue, Buffy.
Author Comment
This is a submission to PeerJ for review.