Knockdown of the putative Lifeguard homologue CG3814 in neurons of Drosophila melanogaster

Abstract

ABSTRACT.Lifeguard is an integral transmembrane protein that modulates FasL-mediated apoptosis by interfering with the activation of caspase 8. It is evolutionarily conserved, with homologues present in plants, nematodes, zebra fish, frog, chicken, mouse, monkey, and human. The Lifeguard homologue in Drosophila, CG3814, contains the Bax inhibitor-1 family motif of unknown function. Downregulation of Lifeguard disrupts cellular homeostasis and disease by sensitizing neurons to FasL-mediated apoptosis. We used bioinformatic analyses to identify CG3814, a putative homologue of Lifeguard, and knocked down CG3814/LFG expression under the control of the Dopa decarboxylase (Ddc-Gal4) transgene in Drosophila melanogaster neurons to investigate whether it possesses neuroprotective activity. Knockdown of CG3814/LFG in Ddc-Gal4-expressing neurons resulted in a shortened lifespan and impaired locomotor ability, phenotypes that are strongly associated with the degeneration and loss of dopaminergic neurons. Lifeguard interacts with anti-apoptotic Bcl-2 proteins and possibly pro-apoptotic proteins to exert its neuroprotective function. The co-expression of Buffy, the sole anti-apoptotic Bcl-2 gene family member in Drosophila, and CG3814/LFG by stable inducible RNA interference, suppresses the shortened lifespan and the premature agedependent loss in climbing ability. Suppression of CG3814/LFG in the Drosophila eye reduces the number of ommatidia and increases disruption of the ommatidial array. Overexpression of Buffy, along with the knockdown of CG3814/LFG, counteracts the eye phenotypes. Knockdown of CG3814/LFG in Ddc-Gal4-expressing neurons in Drosophila diminishes its neuroprotective ability and results in a shortened lifespan and loss of climbing ability, phenotypes that are improved upon overexpression of the pro-survival Buffy.

Up-regulation of apoptotic- and cell survival-related gene pathways following exposures of western corn rootworm to B. thuringiensis crystalline pesticidal proteins in transgenic maize roots

“…SERP also functions within the UPR by enhancing protein stability [ 123 , 124 ]. Somewhat analogously, LFG4 remediates stress in the Golgi and ER [ 117 ], where the single ortholog in D. melanogaster interacts with the anti-apoptotic Bcl-2 protein, buffy, resulting in organismal survival via repression of pro-apoptotic decbl [ 125 ]. BI-1 and LFG4 structure and function are remarkably conserved, where ectopic expression of viral orthologs can rescue knockdown phenotypes in mammalian cells [ 113 ], suggesting retention of ortholog function in D. v. virgifera .…”

In-Vitro Application of Magnetic Hybrid Niosomes: Targeted siRNA-Delivery for Enhanced Breast Cancer Therapy

“…Since siRNA is negatively charged, administration without a protective layer can lead to non-specific binding with serum proteins and, thus, failed cell admission due to electrostatic repulsion to the negatively charged cell membrane [31]. If the target tissue is not reached, the pharmacological properties of the administered siRNA can potentially cause side effects, for example, by the downregulation of LFG in brain cells after crossing the blood-brain barrier [32]. Moreover, the vulnerable nature of siRNA, the nuclease degradation of siRNA in the blood and the possibility of siRNA removal by renal excretion or macrophages generally impede its delivery to the tumor cells [1,33,34].…”