Biology subjects

Moseley, S.

Publications and source records attributed to Moseley, S..

4 recordsLinked to original sources

bioRxiv2023

Genetically encoded, noise-tolerant, auxin biosensors in yeast facilitate metabolic engineering and directed evolution

Auxins are important plant growth regulating compounds that are applied in vast quantities to crops across the globe to control weeds and improve crop quality and yield. Auxins are also produced by nearly every kingdom of life and control both organismal behavior as well as inter-kingdom interactions. Improving our understanding of auxin biosynthesis and signaling is critical to both improving crop plants and controlling symbiotic, commensal, and parasitic inter-kingdom relationships, many of which are critical to ecosystems from forests and oceans to the human microbiome. We present a suite of auxin biosensors that will advance our understanding of and ability to engineer auxin perception by plants and auxin production by fungi. We have developed genetically encoded, ratiometric auxin biosensors in the model yeast Saccharomyces cerevisiae, based on the mechanism plants use to perceive auxin. The ratiometric design of these biosensors improves measurements of auxin concentration by reducing clonal and growth phase variation. These biosensors are capable of measuring exogenous auxin in yeast cultures across five orders of magnitude, likely spanning the physiologically relevant range. We implement these biosensors to measure the production of auxin during different growth conditions and phases for S. cerevisiae. Finally, we demonstrate how these biosensors could be used to improve quantitative functional studies and directed evolution of plant auxin perception machinery. These genetically encoded auxin biosensors will enable future studies of auxin biosynthesis, transport, and signaling in a wide range of yeast species, as well as other fungi, and plants. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=68 SRC="FIGDIR/small/533585v1_ufig1.gif" ALT="Figure 1"> View larger version (17K): org.highwire.dtl.DTLVardef@82743dorg.highwire.dtl.DTLVardef@9d5528org.highwire.dtl.DTLVardef@141cbfaorg.highwire.dtl.DTLVardef@b690e2_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

bioRxiv2022

A thalamo-parietal cortex circuit is critical for place-action coordination

The anterior and lateral thalamus (ALT) contains head direction cells that signal the directional orientation of an animal within an environment. ALT has direct and indirect connections with the parietal cortex (PC), an area hypothesized to play a role in coordinating viewer-dependent and viewer-independent spatial reference frames. This coordination between reference frames would allow an individual to translate movements toward a desired location from memory. Thus ALT-PC functional connectivity would be critical for moving toward remembered locations. This hypothesis was tested with a place-action task that requires associating an appropriate action (left or right turn) with a spatial location. There are four arms, each offset by 90 degrees, positioned around a central starting point. A trial begins in the central starting point. After exiting a pseudorandomly selected arm, the rat had to displace the correct object covering one of two (left versus right) feeding stations to receive a reward. For a pair of arms facing opposite directions, the reward was located on the left, and for the other pair, the reward was located on the right. Thus, each reward location had a different combination of allocentric location and egocentric action. Removal of an object was scored as correct or incorrect. Trials in which the rat did not displace any objects were scored as no response trials. After an object was removed, the rat returned to the center starting position and the maze was reset for the next trial. To investigate the role of the ALT-PC network, muscimol inactivation infusions targeted bilateral PC, bilateral ALT, or the ALT-PC network. Muscimol sessions were counterbalanced and compared to saline sessions within the same animal. All inactivations resulted in decreased accuracy. Only bilateral PC inactivations resulted in increased no response trials, increased errors, and longer latency responses on the remaining trials. Thus, the ALT-PC network is critical for linking an action with a spatial location for successful navigation.

neuroscience↗

bioRxiv2020

Analysis of cell-type-specific chromatin modifications and gene expression in Drosophila neurons that direct reproductive behavior

Examining the role of chromatin modifications and gene expression in neurons is critical for understanding how the potential for behaviors are established and maintained. We investigate this question by examining Drosophila melanogaster fru P1 neurons that underlie reproductive behaviors in both sexes. We developed a method to purify cell-type-specific chromatin (Chromatag), using a tagged histone H2B variant that is expressed using the versatile Gal4/UAS gene expression system. Here, we use Chromatag to evaluate five chromatin modifications, at three life stages in both sexes. We find substantial changes in chromatin modification profiles across development and fewer differences between males and females. We generated cell-type-specific RNA-seq data sets, using translating ribosome affinity purification (TRAP), and identify actively translated genes in fru P1 neurons, revealing novel stage- and sex-differences in gene expression. We compare chromatin modifications to the gene expression data and find patterns of chromatin modifications associated with gene expression. An examination of the genic features where chromatin modifications resides shows certain chromatin modifications are maintained in the same genes across development, whereas others are more dynamic, which may point to modifications important for cell fate determination in neurons. Using a computational analysis to identify super-enhancer-containing genes we discovered differences across development, and between the sexes that are cell-type-specific. A set of super-enhancer-containing genes that overlapped with those determined to be expressed with the TRAP approach were validated as expressed in fru P1 neurons. Author SummaryDifferences in male and female reproductive behaviors are pervasive in nature and important for species propagation. Studies of sex differences in the fruit fly, Drosophila melanogaster, have been ongoing since the early 1900s, with many of the critical molecular and neural circuit determinates that create sexually dimorphic behavior identified. This system is a powerful model to understand fundamental principles about the underpinnings of complex behavior at high resolution. In this study, we examine the gene expression and chromatin modification differences specifically in a set of neurons that direct male and female reproductive behaviors in Drosophila. We describe differences across development and between the sexes with the goal of understanding how the potential for behavior is created and maintained.

genomics↗

bioRxiv2019

Impaired Hippocampal-cortical interactions during sleep and memory reactivation without consolidation in a mouse model of Alzheimer’s disease

Spatial learning is impaired in preclinical Alzheimers disease (AD). We reported similar impairments in 3xTg-AD mice learning a spatial reorientation task. Memory reactivation during sleep is critical for learning related plasticity, and memory consolidation is correlated with hippocampal sharp wave ripple (SWR) density, cortical delta waves (DWs), and their temporal coupling - postulated as a physiological substrate of memory consolidation. Finally, hippocampal-cortical dyscoordination is prevalent in individuals with AD. Thus, we hypothesized impaired memory consolidation mechanisms in hippocampal-cortical networks could account for spatial memory deficits. We assessed sleep architecture, SWR/DW dynamics and memory reactivation in a mouse model of tauopathy and amyloidosis implanted with a recording array targeting isocortex and hippocampus. Mice underwent daily recording sessions of rest-task-rest while learning the spatial reorientation task. We assessed memory reactivation by matching activity patterns from the approach to the unmarked reward zone to patterns during slow wave sleep (SWS). AD mice had more SWS, but reduced SWR density. The increased SWS compensated for reduced SWR density so there was no reduction in SWR number. Conversely, DW density was not reduced so the number of DWs was increased. In control mice hippocampal SWR-cortical DW coupling was strengthened in post-task-sleep and was correlated with performance on the spatial reorientation task the following day. However, in AD mice SWR-DW coupling was reduced and not correlated with behavior, suggesting behavioral decoupling. Thus, reduced SWR-DW coupling may cause impaired learning in AD and may serve as a biomarker for early AD related changes.\n\nSignificance StatementUnderstanding the relationship between network dynamics and cognition early in Alzheimers disease progression is critical for identifying therapeutic targets for earlier treatment. We assessed hippocampal-cortical interactions during sleep in AD mice as a potential cause of early spatial learning and memory deficits. We identified compensatory sleep changes in AD mice, that ameliorated some brain dysfunction. Despite the compensatory changes, impaired spatial navigation and impaired hippocampal-cortical (sharp wave ripple-delta wave) interactions were apparent in AD mice. In control but not AD mice hippocampal-cortical interactions were correlated with performance on the spatial task, the following day, suggesting a potential mechanism of impaired consolidation in AD mice. Thus, changes in hippocampal-cortical brain dynamics during sleep may underlie early memory deficits in AD.

neuroscience↗