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Full-Text Articles in Life Sciences
The Evolution Of Our Thinking About Micrornas, Victor Ambros
The Evolution Of Our Thinking About Micrornas, Victor Ambros
Victor R. Ambros
Our appreciation of the significance of microRNAs to biology at large continues to be an evolving process.
Control Of Developmental Timing In Caenorhabditis Elegans, Victor Ambros
Control Of Developmental Timing In Caenorhabditis Elegans, Victor Ambros
Victor R. Ambros
Studies of the nematode Caenorhabditis elegans have identified genetic and molecular mechanisms controlling temporal patterns of developmental events. Mutations in genes of the C. elegans heterochronic pathway cause altered temporal patterns of larval development, in which cells at certain larval stages execute cell division patterns or differentiation programs normally specific for other stages. The products of the heterochronic genes include transcriptional and translational regulators and two different cases of novel small translational regulatory RNAs. Other genes of the pathway encode evolutionarily conserved proteins, including a homolog of the Drosophila Period circadian timing regulator, and a member of the nuclear receptor …
Structure And Function Analysis Of Lin-14, A Temporal Regulator Of Postembryonic Developmental Events In Caenorhabditis Elegans, Yang Hong, Rosalind C. Lee, Victor R. Ambros
Structure And Function Analysis Of Lin-14, A Temporal Regulator Of Postembryonic Developmental Events In Caenorhabditis Elegans, Yang Hong, Rosalind C. Lee, Victor R. Ambros
Victor R. Ambros
During postembryonic development of Caenorhabditis elegans, the heterochronic gene lin-14 controls the timing of developmental events in diverse cell types. Three alternative lin-14 transcripts are predicted to encode isoforms of a novel nuclear protein that differ in their amino-terminal domains. In this paper, we report that the alternative amino-terminal domains of LIN-14 are dispensable and that a carboxy-terminal region within exons 9 to 13 is necessary and sufficient for in vivo LIN-14 function. A transgene capable of expressing only one of the three alternative lin-14 gene products rescues a lin-14 null mutation and is developmentally regulated by lin-4. This shows …
The Lin-4 Regulatory Rna Controls Developmental Timing In Caenorhabditis Elegans By Blocking Lin-14 Protein Synthesis After The Initiation Of Translation, Philip Olsen, Victor Ambros
The Lin-4 Regulatory Rna Controls Developmental Timing In Caenorhabditis Elegans By Blocking Lin-14 Protein Synthesis After The Initiation Of Translation, Philip Olsen, Victor Ambros
Victor R. Ambros
lin-4 encodes a small RNA that is complementary to sequences in the 3' untranslated region (UTR) of lin-14 mRNA and that acts to developmentally repress the accumulation of LIN-14 protein. This repression is essential for the proper timing of numerous events of Caenorhabditis elegans larval development. We have investigated the mechanism of lin-4 RNA action by examining the fate of lin-14 mRNA in vivo during the time that lin-4 RNA is expressed. Our results indicate that the rate of synthesis of lin-14 mRNA, its state of polyadenylation, its abundance in the cytoplasmic fraction, and its polysomal sedimentation profile do not …
The Timing Oflin-4rna Accumulation Controls The Timing Of Postembryonic Developmental Events Incaenorhabditis Elegans, Rhonda Feinbaum, Victor Ambros
The Timing Oflin-4rna Accumulation Controls The Timing Of Postembryonic Developmental Events Incaenorhabditis Elegans, Rhonda Feinbaum, Victor Ambros
Victor R. Ambros
The lin-4 gene encodes a small RNA that is required to translationally repress lin-14 toward the end of the first larval stage of Caenorhabditis elegans development. To determine if the timing of LIN-14 protein down-regulation depends on the temporal profile of lin-4 RNA level, we analyzed the stage-specificity of lin-4 RNA expression during wild-type development and examined the phenotypes of transgenic worms that overexpress lin-4 RNA during the first larval stage. We found that lin-4 RNA first becomes detectable at approximately 12 h of wild-type larval development and rapidly accumulates to nearly maximum levels by 16 h. This profile of …