Publications by authors named "Chikako Ragan"

Circular RNAs (circRNAs) exhibit unique properties due to their covalently closed nature. Models of circRNAs synthesis and function are emerging but much remains undefined about this surprisingly prevalent class of RNA. Here, we identified exonic circRNAs from human and mouse RNA-sequencing datasets, documenting multiple new examples.

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MicroRNAs (miRNAs) are known to regulate the expression of genes that are important for brain development and function, but the roles of other classes of small non-coding RNAs (sncRNAs) are less well understood. Additionally, although miRNA expression studies have been conducted in post-mortem brain samples from schizophrenia (SCZ) patients, other classes of sncRNAs are yet to be investigated in SCZ. We profiled the expression of miRNAs, piwi-interacting RNAs (piRNAs), small nucleolar RNAs (snoRNAs) and small nuclear RNAs (snRNAs) in SCZ by applying small RNA sequencing (RNA-Seq) to sncRNA isolated from post-mortem anterior cingulate cortex (ACC) of SCZ-affected individuals (n=22) and matched controls (n=22).

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RNA binding proteins (RBPs) control the fate and expression of a transcriptome. Despite this fundamental importance, our understanding of plant RBPs is rudimentary, being mainly derived via bioinformatic extrapolation from other kingdoms. Here, we adapted the mRNA-protein interactome capture method to investigate the RNA binding proteome in planta.

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Article Synopsis
  • The study investigates how the characteristics of oligo-probes affect their ability to hybridize specifically to targeted DNA sequences while minimizing unwanted hybridization across the entire genome.
  • Researchers defined hybridization specificity as the ratio of target-specific hybridization to genome-wide cross-hybridization and analyzed two types of oligo-probes from a microarray database.
  • Findings indicate that certain features, like low duplex stability and G-rich sequences, lead to decreased hybridization specificity, and filtering these 'negative' characteristics can significantly enhance probe design, resulting in probes with twice the specificity.
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RNA functions through the dynamic formation of complexes with RNA-binding proteins (RBPs) in all clades of life. We determined the RBP repertoire of beating cardiomyocytic HL-1 cells by jointly employing two in vivo proteomic methods, mRNA interactome capture and RBDmap. Together, these yielded 1,148 RBPs, 391 of which are shared with all other available mammalian RBP repertoires, while 393 are thus far unique to cardiomyocytes.

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Background: RNA-directed regulation of epigenetic processes has recently emerged as an important feature of mammalian differentiation and development. Perturbation of this regulatory system in the brain may contribute to the development of neuropsychiatric disorders.

Methods: RNA sequencing was used to identify changes in the experience-dependent expression of long noncoding RNAs (lncRNAs) within the medial prefrontal cortex of adult mice.

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Recent advances in RNA sequencing technology (RNA-Seq) enables comprehensive profiling of RNAs by producing millions of short sequence reads from size-fractionated RNA libraries. Although conventional tools for detecting and distinguishing non-coding RNAs (ncRNAs) from reference-genome data can be applied to sequence data, ncRNA detection can be improved by harnessing the full information content provided by this new technology. Here we present NorahDesk, the first unbiased and universally applicable method for small ncRNAs detection from RNA-Seq data.

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MicroRNAs (miRNAs) suppress gene expression by forming a duplex with a target messenger RNA (mRNA), blocking translation or initiating cleavage. Computational approaches have proven valuable for predicting which mRNAs can be targeted by a given miRNA, but currently available prediction methods do not address the extent of duplex formation under physiological conditions. Some miRNAs can at low concentrations bind to target mRNAs, whereas others are unlikely to bind within a physiologically relevant concentration range.

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Transcriptional regulation by microRNAs (miRNAs) involves complementary base-pairing at target sites on mRNAs, yielding complex secondary structures. Here we introduce an efficient computational approach and software (FASTH) for genome-scale prediction of miRNA target sites based on minimizing the free energy of duplex structure. We apply our approach to identify miRNA target sites in the human and mouse transcriptomes.

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