Researchers solve piece of large-scale gene silencing mystery

piggy submitted, created time 1 month 3 days (news-info.wustl.edu)

A team led by Craig Pikaard, Ph.D., Washington University in St. Louis professor of biology in Arts & Sciences, has made a breakthrough in understanding the phenomenon of nucleolar dominance, the silencing of an entire parental set of ribosomal RNA genes in a hybrid plant or animal.

Since the machinery involved in nucleolar dominance is some of the same machinery that can go haywire in diseases such as cancer, Pikaard and his collaborators' research may have important implications for applied medical research

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miRNAs help AID unleashed

Genomic analysis of human microRNA transcripts

jimmy submitted, created time 1 year 2 months (www.pnas.org)

MicroRNAs (miRNAs) are important genetic regulators of development, differentiation, growth, and metabolism. The mammalian genome encodes 500 known miRNA genes. Approximately 50% are expressed from non-protein-coding transcripts, whereas the rest are located mostly in the introns of coding genes.

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Sch9 Is a Major Target of TORC1 in Saccharomyces cerevisiae

Reviver submitted, created time 1 year 6 months (www.molecule.org)

"The p53 tumor suppressor protein is a critical regulator of the cellular response to cancer-initiating insults such as genotoxic stress. In this report, researchers demonstrate that microRNAs (miRNAs) are important components of the p53 transcriptional network. Global miRNA expression analyses identified a cohort of miRNAs that exhibit p53-dependent upregulation following DNA damage. One such miRNA, miR-34a, is commonly deleted in human cancers and, as shown here, frequently absent in pancreatic cancer cells

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An Evolutionarily Conserved Mechanism for MicroRNA-223 Expression Revealed by MicroRNA Gene Profiling

yoyotaxi submitted, created time 1 year 7 months (www.cell.com)

Many microRNAs (miRNAs) are evolutionarily conserved and have intriguing expression patterns. Tissue and/or time-specific expressions of some miRNAs are presumably controlled by unique cis-acting regulatory elements that coevolved with the miRNA sequences. Exploiting bioinformatics, the scientists identified several miRNAs whose primary transcripts could be regulated by conserved genomic elements proximal to their transcription start sites. Such miRNAs include microRNA-223 (miR-223), which is reportedly controlled by a unique regulatory mechanism during granulopoiesis

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Dysregulation of Cardiogenesis, Cardiac Conduction, and Cell Cycle in Mice Lacking miRNA-1-2

medal submitted, created time 1 year 8 months (www.cell.com)

"MicroRNAs (miRNAs) are genomically encoded small RNAs used by organisms to regulate the expression of proteins generated from messenger RNA transcripts. The in vivo requirement of specific miRNAs in mammals through targeted deletion remains unknown, and reliable prediction of mRNA targets is still problematic. Here, we show that miRNA biogenesis in the mouse heart is essential for cardiogenesis

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Maternal microRNAs are essential for mouse zygotic development

athena submitted, created time 1 year 9 months (www.genesdev.org)

"MicroRNAs (miRNAs) have important roles in diverse cellular processes, but little is known about their identity and functions during early mammalian development. Here, we show the effects of the loss of maternal inheritance of miRNAs following specific deletion of Dicer from growing oocytes. The mutant mature oocytes were almost entirely depleted of all miRNAs, and they failed to progress through the first cell division, probably because of disorganized spindle formation

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