expression

Versatility of MicroRNA Biogenesis

by Noam on May 27, 2011

MicroRNAs (miRNAs) are short single-stranded RNA molecules that regulate gene expression. MiRNAs originate from large primary (pri) and precursor (pre) transcripts that undergo various processing steps along their biogenesis pathway till they reach their mature and functional form. It is not clear, however, whether all miRNAs are processed similarly. Here we show that the ratio between pre-miRNA and mature miRNA forms varies between different miRNAs. Moreover, over-expression of several factors involved in miRNA biogenesis, including Exportin-5, Drosha, NF90a, NF45 and KSRP, displayed bidirectional effects on pre/mature miRNA ratios, suggesting their intricate biogenesis sensitivity. In an attempt to identify additional factors that might explain the versatility in miRNA biogenesis we have analyzed the contribution of two hnRNP family members, hnRNPH1 and hnRNPR. Knock-down or over-expression of these genes suggested that hnRNPR inhibits, whereas hnRNPH1 facilitates, miRNA processing. Overall, our results emphasize that miRNA biogenesis is versatile.

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0019391

 

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microRNAs Supplement – Nature

by Chris on December 18, 2009

coverMicroRNAs (miRNAs) are small, non–coding RNAs found in plants and animals. They regulate gene expression by binding to complementary sequences within target mRNAs. The mammalian genome encodes hundreds of miRNAs that collectively affect the expression of about one–third of all genes. This collection showcases the latest papers from Nature that explore the biogenesis, biological effects in both normal and diseased cells, and therapeutic potential of miRNAs. (read more)

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