Project description:In this study, C. gigantea miRNAs and their target genes were investigated by extracting RNA from young roots, tender stems, young leaves, and flower buds of C. gigantea to establish a small RNA (sRNA) library and a degradome library to further sequence. This study identified 194 known miRNAs belonging to 52 miRNA families and 23 novel miRNAs. Among the miRNA families, 158 miRNAs from 27 miRNA families were highly conserved and existed in a plurality of plants. In addition, 60 different targets for 30 known families and one target for novel miRNA were identified by high-throughput sequencing and degradome analysis in C. gigantea. Our analyses showed that conserved miRNAs have higher expression levels and more family members as well as more targets than other miRNAs. Meanwhile, these conserved miRNAs were found to be involved in auxin signal transduction, regulation of transcription, and other developmental processes in plants, which will help further understanding regulatory mechanisms of C. gigantea miRNAs.
Project description:The objective of this work was to determine the effectiveness of cross-hybridization of gDNA from five native soil nematodes to an Affymetrix Caenorhabditis elegans tiling array. Cross-hybridization experiments using C. briggsae, for which genome information is available, allowed hybridisation intensities to be correlated with known sequence differences. Initial analysis of data by conventional array-based Comparative Genomic Hybridization (aCGH) techniques at the chip level lead to misleading results due to an artefact from the combination of scaling, bandwidth smoothing, and differential GC content in exon and intron regions. To circumvent this artefact, individual probes were instead normalized and centered by adjusting for probe-specific thermodynamic binding affinity. However, cross-hybridization of C. briggsae DNA revealed that the resultant probe intensities alone were still uncorrelated to sequence similarity below 90% identity. Below 90% similarity, all probes hybridize uniformly poorly, and above 90% similarity the hybridization differences are not large enough to detect over background, therefore, no 'threshold' ratio of hybridization intensity was successful at identifying probes with similarity to the heterologous genome. In light of the observations described here, we suggest that the criteria for replication and verification of gene expression profiles generated from cross-species microarray hybridizations be more stringent than typically adopted for con-specific hybridizations. Genomic DNA from Caenorhabditis elegans N2 (Bristol), C. elegans CB4856 (Hawaiian), C. briggsae AF16, Oscheius tipulae KS585, Oscheius FVV-2 KS555, Mesorhabditis sp. KS587, Acrobeloides sp. KS586, and Chiloplacus sp. KS584 were hybridized onto C. elegans Affymetrix tiling array (two replicate chips were performed for each species).
Project description:In this study, C. gigantea miRNAs and their target genes were investigated by extracting RNA from young roots, tender stems, young leaves, and flower buds of C. gigantea to establish a small RNA (sRNA) library and a degradome library to further sequence. This study identified 194 known miRNAs belonging to 52 miRNA families and 23 novel miRNAs. Among the miRNA families, 158 miRNAs from 27 miRNA families were highly conserved and existed in a plurality of plants. In addition, 60 different targets for 30 known families and one target for novel miRNA were identified by high-throughput sequencing and degradome analysis in C. gigantea. Our analyses showed that conserved miRNAs have higher expression levels and more family members as well as more targets than other miRNAs. Meanwhile, these conserved miRNAs were found to be involved in auxin signal transduction, regulation of transcription, and other developmental processes in plants, which will help further understanding regulatory mechanisms of C. gigantea miRNAs. The samples were collected from the young roots, tender shoots, young leaves and flower buds of wild C. gigantea growing in Jiangsu Province. TRIzol reagent (Invitrogen, USA) was used to extract the total RNAs [20]. An Illumina next-generation sequencing system, i.e. the 1 G Genome Analyzer sequencing platform, was utilized for sRNA sequencing. An Illumina HiSeq 2000 (LC Sciences, USA) was used for degradome sequencing.