Small RNAs loaded into Argonaute proteins direct silencing of complementary target mRNAs. It has been proposed that multiple, imperfectly small interfering or microRNAs, when bound to the 3′ untranslated region a mRNA, function cooperatively silence expression. We report that, in cultured human HeLa cells and mouse embryonic fibroblasts, Argonaute1 (Ago1), Ago3, Ago4 act both perfectly partially bearing multiple RNA-binding sites. Our data suggest for Ago1, Ago4, adjacent sites facilitate...

Embryonic development requires maternal proteins and RNA. In Caenorhabditis elegans, a gradient of CCCH tandem zinc finger (TZF) coordinates axis polarization germline differentiation. These govern expression from mRNAs by an unknown mechanism. Here we show that the TZF protein MEX-5, primary anterior determinant, is RNA-binding recognizes linear RNA sequences with high affinity but low specificity. The minimal binding site tract six or more uridines within 9-13-nucleotide window. This...

Gene expression and metabolism are coupled at numerous levels. Cells must sense respond to nutrients in their environment, specialized cells synthesize metabolic products required for function. Pluripotent stem have the ability differentiate into a wide variety of cells. How state contributes cell differentiation is not understood. In this study, we show that RNA-binding by translation regulator Musashi-1 (MSI1) allosterically inhibited 18–22 carbon ω-9 monounsaturated fatty acids. The acid...

Inadequate formation and maintenance of myelin is the basis for several neurodegenerative disorders, including leukodystrophy multiple sclerosis. In mice, oligodendrocyte differentiation subsequent requires Quaking gene. Mutation this gene leads to embryonic lethality or a trembling phenotype characteristic dysmyelination. encodes Qk1, member highly conserved STAR/GSG family RNA-binding proteins that function as master developmental regulators in higher eukaryotes. Qk1 has been implicated...

In mice, Quaking (Qk) is required for myelin formation; in humans, it has been associated with psychiatric disease. QK regulates the stability, subcellular localization, and alternative splicing of several myelin-related transcripts, yet little known about how governs these activities. Here, we show that enhances Hnrnpa1 mRNA stability by binding a conserved 3′ UTR sequence high affinity specificity. A single nucleotide mutation site eliminates QK-dependent regulation, as does reduction...

The hairpin ribozyme is a small, naturally occurring RNA capable of folding into distinct three-dimensional structure and catalyzing specific phosphodiester transfer reaction. We have adapted high throughput screening procedure entitled nucleotide analog interference mapping (NAIM) to identify functional groups important for proper catalysis this ribozyme. A total 18 phosphorothioate-tagged analogs were used determine the contribution made by individual ribose 2′-OH purine ligation...

Abstract Gene expression is regulated at multiple levels, including transcription and translation, as well mRNA protein stability. Although systems-level functions of factors microRNAs are rapidly being characterized, few studies have focused on the posttranscriptional gene regulation by RNA binding proteins (RBPs). RBPs important to many aspects regulation. Thus, it essential know which genes encode RBPs, regulate gene(s), how RBP themselves regulated. Here we provide a comprehensive...

RNA-binding proteins (RBPs) coordinate cell fate specification and differentiation in a variety of systems. RNA regulation is critical during oocyte development early embryogenesis, which RBPs control expression from maternal mRNAs encoding key determinants. The Caenorhabditis elegans Notch homologue glp-1 coordinates germline progenitor proliferation anterior embryos. A network sequence-specific required to pattern GLP-1 translation. Here, we map the cis-regulatory elements that guide by...

Great strides in understanding the molecular underpinnings of RNA catalysis have been achieved with advances structure determination by NMR spectroscopy and X-ray crystallography. Despite these successes functional relevance a given can only be assessed upon comparison biochemical studies performed on functioning molecules. The hairpin ribozyme presents an excellent case study for such comparison. active site is comprised two stems each internal loop that forms series non-canonical base...

Myelin-associated glycoprotein (MAG) is a major component of myelin in the vertebrate central nervous system. MAG present periaxonal region structure, where it interacts with neuronal proteins to inhibit axon outgrowth and protect neurons from degeneration. Two alternatively spliced isoforms Mag mRNA have been identified. The encoding shorter isoform, known as S-MAG, contains termination codon exon 12, while longer L-MAG, skips 12 produces protein C-terminal region. L-MAG required How...

How many hits from a high-throughput screen should be sent for confirmatory experiments? Analytical answers to this question are derived statistics alone and aim fix, example, the false discovery rate at predetermined tolerance. These methods, however, neglect local economic context consequently lead irrational experimental strategies. In contrast, authors argue that is essentially economic, not statistical, amenable an analysis admits optimal solution. This solution, in turn, suggests novel...

<ns4:p>RNA-binding proteins play a variety of roles in cellular physiology. Some regulate mRNA processing, abundance, and translation efficiency. fight off invader RNA through small RNA-driven silencing pathways. Others sense foreign sequences the form double-stranded activate innate immune response. Yet others, for example cytoplasmic aconitase, act as bi-functional proteins, processing metabolites one conformation regulating metabolic gene expression another. Not all are involved...