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Animal Cryptochromes Mediate Magnetoreception By An Unconventional Photochemical Mechanism, Robert Gegear, Lauren Foley, Amy Casselman, Steven Reppert
Animal Cryptochromes Mediate Magnetoreception By An Unconventional Photochemical Mechanism, Robert Gegear, Lauren Foley, Amy Casselman, Steven Reppert
Robert J. Gegear
Understanding the biophysical basis of animal magnetoreception has been one of the greatest challenges in sensory biology. Recently it was discovered that the light-dependent magnetic sense of Drosophila melanogaster is mediated by the ultraviolet (UV)-A/blue light photoreceptor cryptochrome (Cry). Here we show, using a transgenic approach, that the photoreceptive, Drosophila-like type 1 Cry and the transcriptionally repressive, vertebrate-like type 2 Cry of the monarch butterfly (Danaus plexippus) can both function in the magnetoreception system of Drosophila and require UV-A/blue light (wavelength below 420 nm) to do so. The lack of magnetic responses for both Cry types at wavelengths above 420 …
The Fly Camta Transcription Factor Potentiates Deactivation Of Rhodopsin, A G Protein-Coupled Light Receptor, Junhai Han, Ping Gong, Keith Reddig, Mirna Mitra, Peiyi Guo, Hong-Sheng Li
The Fly Camta Transcription Factor Potentiates Deactivation Of Rhodopsin, A G Protein-Coupled Light Receptor, Junhai Han, Ping Gong, Keith Reddig, Mirna Mitra, Peiyi Guo, Hong-Sheng Li
Peiyi Guo
Control of membrane-receptor activity is required not only for the accuracy of sensory responses, but also to protect cells from excitotoxicity. Here we report the isolation of two noncomplementary fly mutants with slow termination of photoresponses. Genetic and electrophysiological analyses of the mutants revealed a defect in the deactivation of rhodopsin, a visual G protein-coupled receptor (GPCR). The mutant gene was identified as the calmodulin-binding transcription activator (dCAMTA). The known rhodopsin regulator Arr2 does not mediate this visual function of dCAMTA. A genome-wide screen identified five dCAMTA target genes. Of these, overexpression of the F box gene dFbxl4 rescued the …
Mutation Of A Tadr Protein Leads To Rhodopsin And Gq-Dependent Retinal Degeneration In Drosophila, Lina Ni, Peiyi Guo, Keith Reddig, Mirna Mitra, Hong-Sheng Li
Mutation Of A Tadr Protein Leads To Rhodopsin And Gq-Dependent Retinal Degeneration In Drosophila, Lina Ni, Peiyi Guo, Keith Reddig, Mirna Mitra, Hong-Sheng Li
Peiyi Guo
The Drosophila photoreceptor is a model system for genetic study of retinal degeneration. Many gene mutations cause fly photoreceptor degeneration, either because of excessive stimulation of the visual transduction (phototransduction) cascade, or through apoptotic pathways that in many cases involve a visual arrestin Arr2. Here we report a gene named tadr (for torn and diminished rhabdomeres), which, when mutated, leads to photoreceptor degeneration through a different mechanism. Degeneration in the tadr mutant is characterized by shrunk and disrupted rhabdomeres, the light sensory organelles of photoreceptor. The TADR protein interacted in vitro with the major light receptor Rh1 rhodopsin, and genetic …
Protein Gq Modulates Termination Of Phototransduction And Prevents Retinal Degeneration, Wen Hu, Didi Wan, Xiaoming Yu, Jinguo Cao, Peiyi Guo, Hong-Sheng Li, Junhai Han
Protein Gq Modulates Termination Of Phototransduction And Prevents Retinal Degeneration, Wen Hu, Didi Wan, Xiaoming Yu, Jinguo Cao, Peiyi Guo, Hong-Sheng Li, Junhai Han
Peiyi Guo
Appropriate termination of the phototransduction cascade is critical for photoreceptors to achieve high temporal resolution and to prevent excessive Ca(2+)-induced cell toxicity. Using a genetic screen to identify defective photoresponse mutants in Drosophila, we isolated and identified a novel Galpha(q) mutant allele, which has defects in both activation and deactivation. We revealed that G(q) modulates the termination of the light response and that metarhodopsin/G(q) interaction affects subsequent arrestin-rhodopsin (Arr2-Rh1) binding, which mediates the deactivation of metarhodopsin. We further showed that the Galpha(q) mutant undergoes light-dependent retinal degeneration, which is due to the slow accumulation of stable Arr2-Rh1 complexes. Our study …
Dsarm/Sarm1 Is Required For Activation Of An Injury-Induced Axon Death Pathway, Jeannette Osterloh, Jing Yang, Timothy Rooney, A. Fox, Robert Adalbert, Eric Powell, Amy Sheehan, Michelle Avery, Rachel Hackett, Mary Logan, Jennifer Macdonald, Jennifer Ziegenfuss, Stefan Milde, Ying-Ju Hou, Carl Nathan, Aihao Ding, Robert Brown, Laura Comforti, Michael Coleman, Marc Tessier-Lavigne, Stephan Zuchner, Marc Freeman
Dsarm/Sarm1 Is Required For Activation Of An Injury-Induced Axon Death Pathway, Jeannette Osterloh, Jing Yang, Timothy Rooney, A. Fox, Robert Adalbert, Eric Powell, Amy Sheehan, Michelle Avery, Rachel Hackett, Mary Logan, Jennifer Macdonald, Jennifer Ziegenfuss, Stefan Milde, Ying-Ju Hou, Carl Nathan, Aihao Ding, Robert Brown, Laura Comforti, Michael Coleman, Marc Tessier-Lavigne, Stephan Zuchner, Marc Freeman
Dr Robert Brown
Axonal and synaptic degeneration is a hallmark of peripheral neuropathy, brain injury, and neurodegenerative disease. Axonal degeneration has been proposed to be mediated by an active autodestruction program, akin to apoptotic cell death; however, loss-of-function mutations capable of potently blocking axon self-destruction have not been described. Here, we show that loss of the Drosophila Toll receptor adaptor dSarm (sterile alpha/Armadillo/Toll-Interleukin receptor homology domain protein) cell-autonomously suppresses Wallerian degeneration for weeks after axotomy. Severed mouse Sarm1 null axons exhibit remarkable long-term survival both in vivo and in vitro, indicating that Sarm1 prodegenerative signaling is conserved in mammals. Our results provide direct …