Publications by authors named "J Christopher Rounds"

88 Publications

The RNA-binding protein Nab2 regulates the proteome of the developing Drosophila brain.

J Biol Chem 2021 Jun 15;297(1):100877. Epub 2021 Jun 15.

Department of Cell Biology, Emory University School of Medicine, Emory University, Atlanta, Georgia, USA. Electronic address:

The human ZC3H14 gene, which encodes a ubiquitously expressed polyadenosine zinc finger RNA-binding protein, is mutated in an inherited form of autosomal recessive, nonsyndromic intellectual disability. To gain insight into neurological functions of ZC3H14, we previously developed a Drosophila melanogaster model of ZC3H14 loss by deleting the fly ortholog, Nab2. Studies in this invertebrate model revealed that Nab2 controls final patterns of neuron projection within fully developed adult brains, but the role of Nab2 during development of the Drosophila brain is not known. Here, we identify roles for Nab2 in controlling the dynamic growth of axons in the developing brain mushroom bodies, which support olfactory learning and memory, and regulating abundance of a small fraction of the total brain proteome. The group of Nab2-regulated brain proteins, identified by quantitative proteomic analysis, includes the microtubule-binding protein Futsch, the neuronal Ig-family transmembrane protein turtle, the glial:neuron adhesion protein contactin, the Rac GTPase-activating protein tumbleweed, and the planar cell polarity factor Van Gogh, which collectively link Nab2 to the processes of brain morphogenesis, neuroblast proliferation, circadian sleep/wake cycles, and synaptic development. Overall, these data indicate that Nab2 controls the abundance of a subset of brain proteins during the active process of wiring the pupal brain mushroom body and thus provide a window into potentially conserved functions of the Nab2/ZC3H14 RNA-binding proteins in neurodevelopment.
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http://dx.doi.org/10.1016/j.jbc.2021.100877DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8260979PMC
June 2021

Vocational interests and adverse impact: How attraction and selection on vocational interests relate to adverse impact potential.

J Appl Psychol 2021 Jun 17. Epub 2021 Jun 17.

Department of Psychology.

The current research proposes to incorporate vocational interests into the study of adverse impact (i.e., differential hiring/selection rates between minority and majority groups in employment settings). In the context of high stakes testing (e.g., using cognitive and personality tests), we show how race gaps in vocational interests would correspond to differential rates of job attraction (the attraction process) and various personnel selection outcomes (the selection process), in patterns that are not always intuitive. Using findings from various meta-analyses, we construct a combined correlation matrix of race, vocational interests, cognitive ability, and Conscientiousness; and provide mathematical formulas to assess the role of vocational interests in determining subgroup differences on predictors in applicant pools. Results and empirical examples suggest: (a) applicant attraction based on vocational interests can reduce adverse impact potential when the interest favors the minority [majority] group and is negatively [positively] related to the predictor; (b) attraction effects of vocational interests on adverse impact potential are modest; (c) if the vocational interest subgroup mean difference is small relative to other predictors in use, personnel selection on the interest will reduce adverse impact potential; (d) attraction effects tend to dampen or remove the selection effects of vocational interests on adverse impact potential, due to variance restriction on interests in the applicant pool; and (e) selection effects tend to be much stronger than attraction effects. These findings have implications for how adverse impact might differ systematically across job types, partly due to attraction and selection effects involving race differences in vocational interests. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
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http://dx.doi.org/10.1037/apl0000893DOI Listing
June 2021

Identifying susceptibility genes for primary ovarian insufficiency on the high-risk genetic background of a fragile X premutation.

Fertil Steril 2021 May 17. Epub 2021 May 17.

Department of Human Genetics, Emory University, Atlanta, Georgia. Electronic address:

Objective: To identify modifying genes that explains the risk of fragile X-associated primary ovarian insufficiency (FXPOI).

Design: Gene-based, case/control association study, followed by a functional screen of highly ranked genes using a Drosophila model.

Setting: Participants were recruited from academic and clinical settings.

Patient(s): Women with a premutation (PM) who experienced FXPOI at the age of 35 years or younger (n = 63) and women with a PM who experienced menopause at the age of 50 years or older (n = 51) provided clinical information and a deoxyribonucleic acid sample for whole genome sequencing. The functional screen was on the basis of Drosophila TRiP lines.

Intervention(s): Clinical information and a DNA sample were collected for whole genome sequencing.

Main Outcome Measures: A polygenic risk score derived from common variants associated with natural age at menopause was calculated and associated with the risk of FXPOI. Genes associated with the risk of FXPOI were identified on the basis of the P-value from gene-based association test and an altered level of fecundity when knocked down in the Drosophila PM model.

Results: The polygenic risk score on the basis of common variants associated with natural age at menopause explained approximately 8% of the variance in the risk of FXPOI. Further, SUMO1 and KRR1 were identified as possible modifying genes associated with the risk of FXPOI on the basis of an untargeted gene analysis of rare variants.

Conclusions: In addition to the large genetic effect of a PM on ovarian function, the additive effects of common variants associated with natural age at menopause and the effect of rare modifying variants appear to play a role in FXPOI risk.
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http://dx.doi.org/10.1016/j.fertnstert.2021.04.021DOI Listing
May 2021

Comparing physiological responses during cognitive tests in virtual environments vs. in identical real-world environments.

Sci Rep 2021 May 13;11(1):10227. Epub 2021 May 13.

Department of Design and Environmental Analysis, College of Human Ecology, Cornell University, Ithaca, USA.

Immersive virtual environments (VEs) are increasingly used to evaluate human responses to design variables. VEs provide a tremendous capacity to isolate and readily adjust specific features of an architectural or product design. They also allow researchers to safely and effectively measure performance factors and physiological responses. However, the success of this form of design-testing depends on the generalizability of response measurements between VEs and real-world contexts. At the current time, there is very limited research evaluating the consistency of human response data across identical real and virtual environments. Rendering tools were used to precisely replicate a real-world classroom in virtual space. Participants were recruited and asked to complete a series of cognitive tests in the real classroom and in the virtual classroom. Physiological data were collected during these tests, including electroencephalography (EEG), electrocardiography (ECG), electrooculography (EOG), galvanic skin response (GSR), and head acceleration. Participants' accuracy on the cognitive tests did not significantly differ between the real classroom and the identical VE. However, the participants answered the tests more rapidly in the VE. No significant differences were found in eye blink rate and heart rate between the real and VR settings. Head acceleration and GSR variance were lower in the VE setting. Overall, EEG frequency band-power was not significantly altered between the real-world classroom and the VE. Analysis of EEG event-related potentials likewise indicated strong similarity between the real-world classroom and the VE, with a single exception related to executive functioning in a color-mismatch task.
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http://dx.doi.org/10.1038/s41598-021-89297-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8119471PMC
May 2021

Using Posterior EEG Theta Band to Assess the Effects of Architectural Designs on Landmark Recognition in an Urban Setting.

Front Hum Neurosci 2020 11;14:584385. Epub 2020 Dec 11.

Department of Design and Environmental Analysis, Cornell University, Ithaca, NY, United States.

The process of urban landmark-based navigation has proven to be difficult to study in a rigorous fashion, primarily due to confounding variables and the problem of obtaining reliable data in real-world contexts. The development of high-resolution, immersive virtual reality technologies has opened exciting new possibilities for gathering data on human wayfinding that could not otherwise be readily obtained. We developed a research platform using a virtual environment and electroencephalography (EEG) to better understand the neural processes associated with landmark usage and recognition during urban navigation tasks. By adjusting the architectural parameters of different buildings in this virtual environment, we isolated and tested specific design features to determine whether or not they served as a target for landmarking. EEG theta band (4-7 Hz) event-related synchronization/desynchronization over posterior scalp areas was evaluated at the time when participants observed each target building along a predetermined self-paced route. A multi-level linear model was used to investigate the effects of salient architectural features on posterior scalp areas. Our results support the conclusion that highly salient architectural features-those that contrast sharply with the surrounding environment-are more likely to attract visual attention, remain in short-term memory, and activate brain regions associated with wayfinding compared with non-salient buildings. After establishing this main aggregate effect, we evaluated specific salient architectural features and neural correlates of navigation processing. The buildings that most strongly associated extended gaze time, location recall accuracy, and changes in theta-band neural patterns with landmarking in our study were those that incorporated rotational twist designs and natural elements such as trees and gardens. Other building features, such as unusual façade patterns or building heights, were to a lesser extent also associated with landmarking.
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http://dx.doi.org/10.3389/fnhum.2020.584385DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7759667PMC
December 2020