G-quadruplexes (GQs) are alternative DNA secondary structures that can form throughout the human genome and control the replication and transcription of important regulatory genes. Here, we established an ensemble fluorescence assay by employing two GQ-interacting compounds, N-methyl mesoporphyrin IX (NMM) and Crystal Violet (CV). This enables quantitative measurement of the GQ folding propensity and conformation specificity in both single strand (ss) and double strand (ds) DNA. Our GQ mapping indicates that the likelihood of GQ formation is substantially diminished in dsDNA, likely due to the competition from the Watson–Crick base pairing. Unlike GQ folding sequence in ssDNA which forms both parallel and antiparallel GQs, dsDNA displays only parallel folding. Additionally, we employed single molecule FRET to obtain a direct quantitation of stably formed-, weakly folded and unfolded GQ conformations. The findings of this study and the method developed here will enable identifying and classifying potential GQ-forming sequences in human genome.
Viruses, including retroviruses, can be passed from mothers to their progeny during birth and breastfeeding. It is assumed that newborns may develop immune tolerance to milk-transmitted pathogens similarly to food antigens. I/LnJ mice are uniquely resistant to retroviruses acquired as newborns or as adults as they produce virus-neutralizing antibodies (Abs). A loss-of-function allele of H2-Ob (Ob), originally mapped within the virus infectivity controller 1 (vic1) locus is responsible for production of anti-retrovirus Abs in I/LnJ mice. Importantly, Ob deficient and vic1 I/LnJ congenic mice on other genetic backgrounds produce anti-virus Abs when infected as adults, but not as newborns. We report here that I/LnJ mice carry an additional genetic locus, virus infectivity controller 2 (vic2), that abrogates neonatal immune tolerance to retroviruses. Further genetic analysis mapped the vic2 locus to the telomeric end of chromosome 15. Identification of the vic2 gene and understanding of the related signaling pathways would make blocking of neonatal immune tolerance to retroviruses an achievable goal. Importance This work describes a previously unknown genetic mechanism that allows neonates to respond to infections as efficiently as adults
Author contributions: E.C. assisted in generation and phenotyping of various B6.Ob knock-in mice, genetic analysis of B6J, B6N, and CAST mice, flow cytometry experiments and biochemical experiments, and contributed to the discussion of results and writing and editing the manuscript. L.K.D. designed and performed bone marrow chimera experiments, flow cytometry experiments, biochemical experiments, and also contributed to the discussion of experimental design and results and writing of the manuscript. A.M.G. performed flow cytometry experiments. V.L.T. contributed to the discussion of experimental design and editing the manuscript. T.G. conceived the project, guided the genetic crosses, contributed to all experiments, and wrote the manuscript.
Currently, there are no accessible clinical tests that can be used to measure auditory emotion recognition. Experimental emotion recognition tasks usually involve many stimuli and take a lot of time to complete, making them unfeasible for use in a clinical setting. Prior research from our laboratory has measured the impact of various test factors on auditory emotion recognition, including the number of emotion categories, the number of stimuli per emotion category, the number of talkers, and using sentence versus word materials. In this study, we present a preliminary validation of a proposed audiotry emotion recognition test. Based on the results from our laboratory, the test consists of forty sentences (1 sentence × 10 talkers × 4 emotions) in order to maintain an appropriate test duration for a clinical setting. Listeners with normal hearing will complete the testing in quiet. Results will be compared with expectations informed by prior research. Performance and duration of the task will be measured, and standard deviation of scores among all participants will be assessed. Implications will be discussed, including the percentage correct of emotion recognition by normal hearing listeners.
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