Most of the vertebrate genome is transcribed into RNA. Transcribed regions contain hundreds of thousands of potential duplex structures that could serve as substrates for RNAse III enzymes of microRNA (miRNA) maturation pathways. Yet, only a minority of these potential precursors make their way to the cytoplasm to form mature miRNAs. We question here what specific structural features make an RN...

The aim of this study was to investigate the mechanisms by which troxerutin protects cells against ultraviolet B (UVB) radiation. First, we demonstrate that pre-treatment with troxerutin protects normal human dermal fibroblasts (nHDFs) against UVB-induced cytotoxicity. As shown by migration assay and DNA repair analysis, troxerutin increased cell migration and DNA repair activity in the nHDFs. ...

In this study, a modified miRsearch program was developed in C++ for the detection of miRNAs. All the mature miRNA sequences of Caenorhabditis elegans, Caenorhabditis briggsae, Caenorhabditis remanei, Drosophila melanogaster, Homo sapiens and Rattus norvegicus available in miRbase was searched by this program for homologous sequences with a maximum of 3-mismatches in the chromosomes of C. elega...

MicroRNAs (miRNAs) constitute a class of small cellular RNAs (typically 21-23nt) that function as post-transcriptional regulators of gene expression. Current estimates indicate that more than one third of the cellular transcriptome is regulated by miRNAs, although they are relatively few in number (less than 2000 human miRNAs). The high relative stability of miRNA in common clinical tissues and...

To date, the vast majority of known virus-encoded microRNAs (miRNAs) are derived from polymerase II transcripts encoded by DNA viruses. A recent demonstration that the bovine leukemia virus, a retrovirus, uses RNA polymerase III to directly transcribe the pre-miRNA hairpins to generate viral miRNAs further supports the common notion that the canonical pathway of miRNA biogenesis does not exist ...

The canonical microRNA (miRNA) pathway commences with the enzymatic cleavage of the primary gene transcript (pri-miRNA) by the RNAase III enzyme Drosha in the nucleus into shorter pre-miRNA species that are subsequently exported to the cytoplasm for further processing into shorter, mature miRNA molecules. Using a series of reporter constructs, we have previously demonstrated that phosphorylatio...

Processing of miRNAs occurs simultaneous with the transcription and splicing of their primary transcripts. For the small subset of exonic miRNAs it is unclear if the unspliced and/or spliced transcripts are used for miRNA biogenesis. We assessed endogenous levels and cellular location of primary transcripts of three exonic miRNAs. The ratio between unspliced and spliced transcripts varied marke...

Small RNA molecules, including microRNAs (miRNAs), play critical roles in regulating pluripotency, proliferation and differentiation of embryonic stem cells. miRNA-offset RNAs (moRNAs) are similar in length to miRNAs, align to miRNA precursor (pre-miRNA) loci and are therefore believed to derive from processing of the pre-miRNA hairpin sequence. Recent next generation sequencing (NGS) studies h...

The canonical microRNA (miRNA) pathway converts primary hairpin precursor transcripts into approximately 22 nucleotide regulatory RNAs via consecutive cleavages by two RNase III enzymes, Drosha and Dicer. In this study, we characterize Drosophila small RNAs that derive from short intronic hairpins termed "mirtrons." Their nuclear biogenesis appears to bypass Drosha cleavage, which is essential ...