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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 ...


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

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

Program in Molecular Medicine Publications and Presentations

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 ...


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 ...


Effect Of Life History On Microrna Expression During C. Elegans Development, Xantha Karp, Molly Hammell, Maria C. Ow, Victor R. Ambros Apr 2011

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

Program in Molecular Medicine Publications and Presentations

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 ...


Sorting Of Drosophila Small Silencing Rnas Partitions Microrna* Strands Into The Rna Interference Pathway, Megha Ghildiyal, Jia Xu, Herve Seitz, Zhiping Weng, Phillip D. Zamore Jan 2010

Sorting Of Drosophila Small Silencing Rnas Partitions Microrna* Strands Into The Rna Interference Pathway, Megha Ghildiyal, Jia Xu, Herve Seitz, Zhiping Weng, Phillip D. Zamore

GSBS Student Publications

In flies, small silencing RNAs are sorted between Argonaute1 (Ago1), the central protein component of the microRNA (miRNA) pathway, and Argonaute2 (Ago2), which mediates RNA interference. Extensive double-stranded character-as is found in small interfering RNAs (siRNAs)-directs duplexes into Ago2, whereas central mismatches, like those found in miRNA/miRNA* duplexes, direct duplexes into Ago1. Central to this sorting decision is the affinity of the small RNA duplex for the Dcr-2/R2D2 heterodimer, which loads small RNAs into Ago2. Here, we show that while most Drosophila miRNAs are bound to Ago1, miRNA* strands accumulate bound to Ago2. Like siRNA loading, efficient ...


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

Program in Molecular Medicine Publications and Presentations

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 ...