Re-Inspection of Small RNA Sequence Datasets Reveals Several Novel Human miRNA Genes

Background: miRNAs are key players in gene expression regulation. To fully understand the complex nature of cellular differentiation or initiation and progression of disease, it is important to assess the expression patterns of as many miRNAs as possible. Thereby, identifying novel miRNAs is an essential prerequisite to make possible a comprehensive and coherent understanding of cellular biology. Methodology/Principal Findings: Based on two extensive, but previously published, small RNA sequence datasets from human embryonic stem cells and human embroid bodies, respectively [1], we identified 112 novel miRNA-like structures and were able to validate miRNA processing in 12 out of 17 investigated cases. Several miRNA candidates were furthermore substantiated by including additional available small RNA datasets, thereby demonstrating the power of combining datasets to identify miRNAs that otherwise may be assigned as experimental noise. Conclusions/Significance: Our analysis highlights that existing datasets are not yet exhaustedly studied and continuous reanalysis of the available data is important to uncover all features of small RNA sequencing. © 2010 Hansen et al.