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Full-Text Articles in Molecular Biology

Staufen Negatively Modulates Microrna Activity In Caenorhabditis Elegans, Zhiji Ren, Isana Veksler-Lublinsky, David Morrissey, Victor Ambros Mar 2016

Staufen Negatively Modulates Microrna Activity In Caenorhabditis Elegans, Zhiji Ren, Isana Veksler-Lublinsky, David Morrissey, Victor Ambros

Victor R. Ambros

The double-stranded RNA-binding protein Staufen has been implicated in various post-transcriptional gene regulatory processes. Here we demonstrate that the Caenorhabditis elegans homolog of Staufen, STAU-1, functionally interacts with microRNAs. Loss-of-function mutations of stau-1 significantly suppress phenotypes of let-7 family microRNA mutants, a hypomorphic allele of dicer and a lsy-6 microRNA partial loss-of-function mutant. Furthermore, STAU-1 modulates the activity of lin-14, a target of lin-4 and let-7 family microRNAs, and this modulation is abolished when the 3' untranslated region of lin-14 is removed. Deep sequencing of small RNA cDNA libraries reveals no dramatic change in the levels of microRNAs, or other ...


Inhibiting Mirna In Caenorhabditis Elegans Using A Potent And Selective Antisense Reagent, Genhua Zheng, Victor R. Ambros, Wen-Hong Li Oct 2015

Inhibiting Mirna In Caenorhabditis Elegans Using A Potent And Selective Antisense Reagent, Genhua Zheng, Victor R. Ambros, Wen-Hong Li

Victor R. Ambros

BACKGROUND: Antisense reagents can serve as efficient and versatile tools for studying gene function by inhibiting nucleic acids in vivo. Antisense reagents have particular utility for the experimental manipulation of the activity of microRNAs (miRNAs), which are involved in the regulation of diverse developmental and physiological pathways in animals. Even in traditional genetic systems, such as the nematode Caenorhabditis elegans, antisense reagents can provide experimental strategies complementary to mutational approaches. Presently no antisense reagents are available for inhibiting miRNAs in the nematode C. elegans. RESULTS: We have developed a new class of fluorescently labelled antisense reagents to inhibit miRNAs in ...


Systematic Analysis Of Dynamic Mirna-Target Interactions During C. Elegans Development, Liang Zhang, Molly Hammell, Brian Kudlow, Victor Ambros, Min Han Oct 2015

Systematic Analysis Of Dynamic Mirna-Target Interactions During C. Elegans Development, Liang Zhang, Molly Hammell, Brian Kudlow, Victor Ambros, Min Han

Victor R. Ambros

Although microRNA (miRNA)-mediated functions have been implicated in many aspects of animal development, the majority of miRNA::mRNA regulatory interactions remain to be characterized experimentally. We used an AIN/GW182 protein immunoprecipitation approach to systematically analyze miRNA::mRNA interactions during C. elegans development. We characterized the composition of miRNAs in functional miRNA-induced silencing complexes (miRISCs) at each developmental stage and identified three sets of miRNAs with distinct stage-specificity of function. We then identified thousands of miRNA targets in each developmental stage, including a significant portion that is subject to differential miRNA regulation during development. By identifying thousands of miRNA ...


Effect Of Life History On Microrna Expression During C. Elegans Development, Xantha Karp, Molly Hammell, Maria C. Ow, Victor R. Ambros Oct 2015

Effect Of Life History On Microrna Expression During C. Elegans Development, Xantha Karp, Molly Hammell, Maria C. Ow, Victor R. Ambros

Victor R. Ambros

Animals have evolved mechanisms to ensure the robustness of developmental outcomes to changing environments. MicroRNA expression may contribute to developmental robustness because microRNAs are key post-transcriptional regulators of developmental gene expression and can affect the expression of multiple target genes. Caenorhabditis elegans provides an excellent model to study developmental responses to environmental conditions. In favorable environments, C. elegans larvae develop rapidly and continuously through four larval stages. In contrast, in unfavorable conditions, larval development may be interrupted at either of two diapause stages: The L1 diapause occurs when embryos hatch in the absence of food, and the dauer diapause occurs ...


Micrornas: Genetically Sensitized Worms Reveal New Secrets, Victor Ambros Oct 2015

Micrornas: Genetically Sensitized Worms Reveal New Secrets, Victor Ambros

Victor R. Ambros

Why do many microRNA gene mutants display no evident phenotype? Multiply mutant worms that are selectively impaired in genetic regulatory network activities have been used to uncover previously unknown functions for numerous Caenorhabditis elegans microRNAs.


In The Tradition Of Science: An Interview With Victor Ambros, Victor R. Ambros Oct 2015

In The Tradition Of Science: An Interview With Victor Ambros, Victor R. Ambros

Victor R. Ambros

No abstract provided.


A Feedback Circuit Involving Let-7-Family Mirnas And Daf-12 Integrates Environmental Signals And Developmental Timing In Caenorhabditis Elegans, Christopher M. Hammell, Xantha Karp, Victor R. Ambros Nov 2009

A Feedback Circuit Involving Let-7-Family Mirnas And Daf-12 Integrates Environmental Signals And Developmental Timing In Caenorhabditis Elegans, Christopher M. Hammell, Xantha Karp, Victor R. Ambros

Victor R. Ambros

Animal development is remarkably robust; cell fates are specified with spatial and temporal precision despite physiological and environmental contingencies. Favorable conditions cause Caenorhabditis elegans to develop rapidly through four larval stages (L1-L4) to the reproductive adult. In unfavorable conditions, L2 larvae can enter the developmentally quiescent, stress-resistant dauer larva stage, enabling them to survive for prolonged periods before completing development. A specific progression of cell division and differentiation events occurs with fidelity during the larval stages, regardless of whether an animal undergoes continuous or dauer-interrupted development. The temporal patterning of developmental events is controlled by the heterochronic genes, whose products ...