MicroRNAs (miRNAs) form an extensive class of RNA molecules that regulate gene expression at post-transcriptional level. In recent years, much progress has been made in dissection of biogenesis and functions of miRNAs. There are at least several hundred miRNA genes in the human genome, and the emerging evidence suggests that miRNAs are broadly implicated in gene regulation. Here, we review some...

UNLABELLED The liver is one of the few organs that have the capacity to regenerate in response to injury. We carried out genomewide microRNA (miRNA) microarray studies during liver regeneration in rats after 70% partial hepatectomy (PH) at early and mid time points to more thoroughly understand their role. At 3, 12, and 18 hours post-PH ∼40% of the miRNAs tested were up-regulated. Conversely, a...

Canonical microRNA biogenesis requires the Microprocessor components, Drosha and DGCR8, to generate precursor-miRNA, and Dicer to form mature miRNA. The Microprocessor is not required for processing of some miRNAs, including mirtrons, in which spliceosome-excised introns are direct Dicer substrates. In this study, we examine the processing of putative human mirtrons and demonstrate that althoug...

One of the most exciting aspects of the genomic era during the last fifteen years has been the discovery of RNA interference pathways and their key function in gene regulation in eucaryotes. RNAi has rapidly invaded our laboratories and has become the gold standard technique to investigate the function of a given gene. In parallel, intensive research on microRNAs (miRNAs) has underlined their w...

Human cancers often exhibit increased microRNA (miRNA) biogenesis and global aberrant expression of miRNAs; thus, targeting the miRNA biogenesis pathway represents a novel strategy for cancer therapy. Here, we report that miR-203 enhances the biogenesis of tumor suppressor let-7 in lung cancer by directly targeting LIN28B. Specially, we found that the LIN28B protein levels were dramatically inc...

Global downregulation of microRNAs (miRNAs) is a common feature of human tumors and has been shown to enhance cancer progression. Several components of the miRNA biogenesis machinery (XPO5, DICER and TRBP) have been shown to act as haploinsufficient tumor suppressors. How the deregulation of miRNA biogenesis promotes tumor development is not clearly understood. Here we show that loss of miRNA b...

Abstract By 2003, the Human Genome project had been completed; however, it turned out that 97% of genome sequences did not encode proteins. The explanation came later when was found untranslated DNA contain for short microRNAs (miRNAs) and long noncoding RNAs produce any mRNAs or tRNAs, but instead were involved in regulation gene expression. Initially identified cytoplasm, miRNAs have all cell...

Dysregulation of miRNAs expression plays a critical role in the pathogenesis of genetic, multifactorial disorders and in human cancers. We exploited sequence, genomic and expression information to investigate two main aspects of post-transcriptional regulation in miRNA biogenesis, namely strand selection regulation and expression relationships between intragenic miRNAs and host genes. We consid...

Understanding origin, evolution and functions of small RNA (sRNA) genes has been a great challenge in the past decade. Molecular mechanisms underlying sexual reversal in vertebrates, particularly sRNAs involved in this process, are largely unknown. By deep-sequencing of small RNA transcriptomes in combination with genomic analysis, we identified a large amount of piRNAs and miRNAs including ove...

MicroRNAs (miRNAs) are a recently discovered class of small, non-coding RNAs that regulate protein levels post-transcriptionally. miRNAs play important regulatory roles in many cellular processes, including differentiation, neoplastic transformation, and cell replication and regeneration. Because of these regulatory roles, it is not surprising that aberrant miRNA expression has been implicated ...