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Ricker, B.

Publications and source records attributed to Ricker, B..

4 recordsLinked to original sources

Magneto-Photonic Gene Circuit for Minimally Invasive Control of Gene Expression in Mammalian Cells

Precise control of gene expression is one of the fundamental goals of synthetic biology. Whether the objective is to modify endogenous cellular function or induce the expression of molecules for diagnostic and therapeutic purposes, gene regulation remains a key aspect of biological systems. Over time, advances in protein engineering and molecular biology have led to the creation of gene circuits capable of inducing the expression of specific proteins in response to external stimulus such as light. These optogenetic, or light-activated circuits hold significant potential for gene therapy as a tool for regulating the expression of therapeutic genes within cells. However, the applications of optogenetic systems can be limited by the lack of efficient ways for light delivery inside cells or tissue. Our approach to address this challenge is to harness the power of bioluminescence to produce light directly inside cells using a luminescent enzyme. Combined with a photosensitive transcription factor, we report the development of a fully genetically encoded optogenetic circuit for control of gene expression. Furthermore, we utilized a magneto sensitive protein to engineer a split protein version of this luminescent enzyme, where its reconstitution is driven by a 50mT magnetic stimulus. Thus, resulting in a first-of-its-kind gene circuit activated by a combination of light and magnetic stimulus. We expect this work to advance the implementation of light-controlled systems without the need of external light sources, as well as serve as a basis for the development of future magneto-sensitive tools.

synthetic biology↗

Using Manganese-Enhanced MRI to visualize Magnetogenetic-based Neuromodulation

PurposeInvestigation of the electromagnetic perceptive gene (EPG) protein and garnering evidence to suggest its use as a magnetogenetic tool for neuromodulation. Activation of EPG by electromagnetic field increases intracellular calcium levels, thus, we aimed to determine whether EPG influences the analogous manganese ion. This work yields potential for manganese-enhanced MRI (MEMRI) to be used to monitor EPG acting as a neuromodulator. MethodsHEK293FT cells expressing EPG were exposed to a MnCl2 solution and stimulated with a static or electromagnet. Excess MnCl2 was washed off the cells, followed by their collection and lysis. T1 map measurements of the lysates were obtained to gauge the presence of intracellular Mn2+. Several controls were employed to critically evaluate whether EPG can influence Mn2+ dynamics. ResultsLysate of cells expressing EPG showed significantly lower T1 values compared to cells without EPG that were exposed to the same MnCl2 solution and magnetic stimulus. ConclusionMagnetic activation of EPG increases the uptake of Mn2+ into the cell. By influencing ions pertinent to neuronal function, we demonstrate the potential of MEMRI to monitor EPG neuromodulatory activity.

biophysics↗

A conserved phenylalanine motif among Teleost fish provides insight for improving electromagnetic perception.

Magnetoreceptive biology as a field remains relatively obscure; compared to the breadth of species believed to sense magnetic fields, it remains under-studied. Here, we present grounds for the expansion of magnetoreception studies among Teleosts. We begin with the electromagnetic perceptive gene (EPG) from Kryptopterus vitreolus and expand to identify 72 Teleosts with homologous proteins containing a conserved three-phenylalanine (3F) motif. Phylogenetic analysis provides insight as to how EPG may have evolved over time, and indicates that certain clades may have experienced a loss of function driven by different fitness pressures. One potential factor is water type with freshwater fish significantly more likely to possess the functional motif version (FFF), and saltwater fish to have the non-functional variant (FXF). It was also revealed that when the 3F motif from the homolog of Brachyhypopomus gauderio (B.g.) is inserted into EPG - EPG(B.g.) - the response (as indicated by increased intracellular calcium) is faster. This indicates that EPG has the potential to be engineered to improve upon its response and increase its utility to be used as a controller for specific outcomes.

synthetic biology↗

Proposed three-phenylalanine motif involved in magnetoreception signaling of an Actinopterygii protein expressed in mammalian cells

Studies at the cellular and molecular level of magnetoreception - sensing and responding to magnetic fields - is a relatively new research area. As it appears that different mechanisms of magnetoreception in animals evolved from different origins, many questions about the mechanisms remain left open. Here we present new information regarding the Electromagnetic Perceptive Gene (EPG) from Kryptopterus vitreolus that may serve as part of the foundation to understanding and applying magnetoreception. Using HaloTag coupled with fluorescent ligands and phosphatidylinositol specific phospholipase C (PI-PLC) we show that EPG is associated to the membrane via glycosylphosphatidylinositol (GPI) anchor. EPGs function of increasing intracellular calcium was also used to generate an assay using GCaMP6m to observe the function of EPG and to compare its function with homologous proteins. It was also revealed that EPG relies on a motif of three phenylalanine residues in order to function - stably swapping these residues using site directed mutagenesis resulted in a loss of function in EPG. This information not only expands upon our current understanding of magnetoreception but may provide a foundation and template to continue characterizing and discovering more within the field. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/519643v1_ufig1.gif" ALT="Figure 1"> View larger version (58K): org.highwire.dtl.DTLVardef@19a4f54org.highwire.dtl.DTLVardef@1ce17b2org.highwire.dtl.DTLVardef@175b97borg.highwire.dtl.DTLVardef@1e45294_HPS_FORMAT_FIGEXP M_FIG C_FIG In BriefEPG is a magnetoreceptive GPI anchored protein. Critical to its function is a three-phenylalanine motif which allows EPG to sense and respond to EMF. When expressed in mammalian cell, an increase in intracellular calcium is observed using GCaMP6m. This work represents progress towards understanding magnetoreception for use in future technologies. HighlightsO_LIEPG is associated to the cell membrane via glycosylphosphatidylinositol anchoring C_LIO_LIIn mammalian cells, EPG increases intracellular calcium upon EMF stimulation C_LIO_LIHomologs of EPG from the uPAR/Ly6 family show different responses to EMF C_LIO_LIA three-phenylalanine motif in EPG is critical to its magnetoreceptive ability C_LI

molecular biology↗