Project description:Human cells generate a vast complexity of non-coding RNAs, the so called “RNA dark matter”, which includes small RNA transcriptome represented by hundreds of thousands of entities which outnumber members of known classes of small RNAs by orders of magnitude. Biogenesis, biological relevance, and mechanisms of action of most of these transcripts remain unknown and many of them are assumed to represent degradation products of known genes. In this study, we aimed to functionally characterize human sRNA transcriptome by attempting to answer the following question — can a significant number of novel sRNAs correspond to novel members of known classes of sRNA, specifically, miRNAs? We show that at the very least, 2726 novel miRNAs exist in just one human cell line. Furthermore, potentially thousands other novel members of this class may exist. Strikingly, many novel miRNAs are derived from exons of protein-coding genes. These results suggest that mammalian novel sRNA transcriptome harbors multitude of novel functional transcripts, at least some of which belong to known classes of sRNAs.
Project description:We determined pattern of miRNAs of mild-to-severe human pulmonary arterial hypertension and compared the with health controls using microarray and subsequently validated by QPCRs Manuscript Title: Circulating miRNAs as novel marker for pulmonary hypertension. (Under Revision Plos One Manuscript ID: PONE-D-12-38535)
Project description:Motivation: MicroRNAs (miRNAs) are short regulatory RNAs derived from a longer precursor RNA. miRNA biogenesis has been studied in animals and plants, recently elucidating more diverse and complex aspects, such as non-conserved, speciesspecific, and heterogeneous miRNA precursor populations. Small RNA sequencing data can be used to computationally determine genomic loci of miRNA precursors. The challenge is to predict a valid miRNA precursor from inhomogeneous read coverage: while the mature miRNA typically produces hundreds of sequence reads, the remaining part of the precursor is covered very sparsely. Results: We introduce a new conservation-independent method for the identification of miRNA precursors, that allows for speciesspecific heterogeneous precursor populations. The algorithm requires small RNA sequencing data and evaluates precursor secondary structures, with key parameters that can be adjusted based on the specific organism under investigation (within animals, plants, algae). We illustrate the validity of results from our algorithm using sequencing data for the two Volvocine algae Chlamydomonas reinhardtii (Chlamydomonas) and Volvox carteri (Volvox). Both organisms show little cross-species miRNA sequence conservation, and a heterogeneous miRNA precursor population. We validate our list of Chlamydomonas miRNAs with annotated miRNAs, and demonstrate excellent agreement. Furthermore, we are able to identify additional novel miRNA precursors, with structures ranging from simple mammalian-like hairpins to precursor structures indicating the creation of multiple mature/star miRNA duplexes. Novel miRNAs identified in Volvox show no similarity to mature miRNAs in Chlamydomonas. These results confirm the need for conservationindependent miRNA identification methods.
Project description:MicroRNAs (miRNAs) are a class of small, non-coding regulatory RNAs that regulate gene expression by guiding target mRNA cleavage or translational inhibition in plants and animals. At present there is relatively little information regarding the role of miRNAs in the response to drought stress in maize. In this study, two small RNA libraries were sequenced, and a total of 11,973,711 and 14,326,010 raw sequences were generated from growing leaves of drought-tolerant and drought-sensitive maize seedlings, respectively. Further analysis identified 192 mature miRNAs, which include 124 known maize (zma) miRNAs and 68 potential novel miRNA candidates. Additionally, 167 target genes (259 transcripts) of known and novel miRNAs were predicted to be differentially expressed between two maize inbred lines. Of these, three novel miRNAs were up-regulated and two were down-regulated under drought stress. The expression of these five miRNAs and nine target genes was confirmed using quantitative reverse transcription PCR. The expression of three of the miRNAs and their putative target genes exhibited an inverse correlation, and expression analysis suggested that all five may play important roles in maize leaves. Finally, GO annotations of the target genes indicated a potential role in photosynthesis, may therefore contribute to the drought stress response. This study describes the identification and characterization of novel miRNAs that are the differentially expressed in drought-tolerant and drought-sensitive inbred maize lines. This provides the foundation for further investigation into the mechanism of miRNA function in response to drought stress in maize.
Project description:Motivation: MicroRNAs (miRNAs) are short regulatory RNAs derived from a longer precursor RNA. miRNA biogenesis has been studied in animals and plants, recently elucidating more diverse and complex aspects, such as non-conserved, speciesspecific, and heterogeneous miRNA precursor populations. Small RNA sequencing data can be used to computationally determine genomic loci of miRNA precursors. The challenge is to predict a valid miRNA precursor from inhomogeneous read coverage: while the mature miRNA typically produces hundreds of sequence reads, the remaining part of the precursor is covered very sparsely. Results: We introduce a new conservation-independent method for the identification of miRNA precursors, that allows for speciesspecific heterogeneous precursor populations. The algorithm requires small RNA sequencing data and evaluates precursor secondary structures, with key parameters that can be adjusted based on the specific organism under investigation (within animals, plants, algae). We illustrate the validity of results from our algorithm using sequencing data for the two Volvocine algae Chlamydomonas reinhardtii (Chlamydomonas) and Volvox carteri (Volvox). Both organisms show little cross-species miRNA sequence conservation, and a heterogeneous miRNA precursor population. We validate our list of Chlamydomonas miRNAs with annotated miRNAs, and demonstrate excellent agreement. Furthermore, we are able to identify additional novel miRNA precursors, with structures ranging from simple mammalian-like hairpins to precursor structures indicating the creation of multiple mature/star miRNA duplexes. Novel miRNAs identified in Volvox show no similarity to mature miRNAs in Chlamydomonas. These results confirm the need for conservationindependent miRNA identification methods. Examination of small RNAs of Volvox carteri during different stages of its life cycle
Project description:We determined pattern of miRNAs of mild-to-severe human pulmonary arterial hypertension and compared the with health controls using microarray and subsequently validated by QPCRs Manuscript Title: Circulating miRNAs as novel marker for pulmonary hypertension. (Under Revision Plos One Manuscript ID: PONE-D-12-38535) Performed microRNA microarray from one healthy and one severe PH patient and compared the results using additional samples by qPCR for other miRNAs
Project description:In this study, we hypothesized that IL-27 could induce the expression of novel miRNAs in macrophages which may have functional relevance in terms of anti-viral activity. In this study, primary monocytes were differentiated into macrophages using M-CSF (M-Mac) or with a combination of M-CSF and IL-27 (I-Mac) for seven days. Following this, total RNA was extracted from these cells and deep sequencing was performed, in parallel with gene expression microarrays. Using the novel miRNA discovery software, miRDeep, seven novel miRNAs were discovered in the macrophages, four of which were expressed higher in I-Mac (miRNAs 2.1, 8.1, 9.1 and 14.2) whilst three were detected in both M-Mac and I-Mac (miRNAs 9.3, 13.6 and 15.8). The expression of six of the seven novel miRNAs was highly correlated with qRT-PCR using specific primer/probes designed for the novel miRNAs. Gene expression microarray further demonstrated that a number of genes were potentially targeted by these differentially expressed novel miRNAs.
Project description:Atherosclerosis (AS), which is a chronic inflammatory disease, is the leading cause of death worldwide. Although several miRNAs have been reported to participate in regulating the progression of AS, there is a lack of systematic study of miRNA profile in AS. We combined miRNA and mRNA array analysis to study the global miRNAs in two AS models-oxidative LDL treated human aortic endothelial cells (HAEC) and high fat diet fed ldlr W483Stop knockin mouse. Novel miRNAs were identified to function in AS through inflammation and apoptosis pathways.