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Articles 1 - 7 of 7
Full-Text Articles in Medicine and Health Sciences
Genome-Scale Spatiotemporal Analysis Of Caenorhabditis Elegans Microrna Promoter Activity, Natalia Julia Martinez, Maria C. Ow, John S. Reece-Hoyes, M. Inmaculada Barrasa, Victor R. Ambros, Albertha J. M. Walhout
Genome-Scale Spatiotemporal Analysis Of Caenorhabditis Elegans Microrna Promoter Activity, Natalia Julia Martinez, Maria C. Ow, John S. Reece-Hoyes, M. Inmaculada Barrasa, Victor R. Ambros, Albertha J. M. Walhout
Victor R. Ambros
The Caenorhabditis elegans genome encodes more than 100 microRNAs (miRNAs). Genetic analyses of miRNA deletion mutants have only provided limited insights into miRNA function. To gain insight into the function of miRNAs, it is important to determine their spatiotemporal expression pattern. Here, we use miRNA promoters driving the expression of GFP as a proxy for miRNA expression. We describe a set of 73 transgenic C. elegans strains, each expressing GFP under the control of a miRNA promoter. Together, these promoters control the expression of 89 miRNAs (66% of all predicted miRNAs). We find that miRNA promoters drive GFP expression in …
Nhl-2 Modulates Microrna Activity In Caenorhabditis Elegans, Christopher Hammell, Isabella Lubin, Peter Boag, T. Keith Blackwell, Victor Ambros
Nhl-2 Modulates Microrna Activity In Caenorhabditis Elegans, Christopher Hammell, Isabella Lubin, Peter Boag, T. Keith Blackwell, Victor Ambros
Victor R. Ambros
TRIM-NHL proteins represent a large class of metazoan proteins implicated in development and disease. We demonstrate that a C. elegans TRIM-NHL protein, NHL-2, functions as a cofactor for the microRNA-induced silencing complex (miRISC) and thereby enhances the posttranscriptional repression of several genetically verified microRNA targets, including hbl-1 and let-60/Ras (by the let-7 family of microRNAs) and cog-1 (by the lsy-6 microRNA). NHL-2 is localized to cytoplasmic P-bodies and physically associates with the P-body protein CGH-1 and the core miRISC components ALG-1/2 and AIN-1. nhl-2 and cgh-1 mutations compromise the repression of microRNA targets in vivo but do not affect microRNA …
The Flywch Transcription Factors Flh-1, Flh-2, And Flh-3 Repress Embryonic Expression Of Microrna Genes In C. Elegans, Maria C. Ow, Natalia Julia Martinez, Philip H. Olsen, Howard S. Silverman, M. Inmaculada Barrasa, Barbara Conradt, Albertha J. M. Walhout, Victor R. Ambros
The Flywch Transcription Factors Flh-1, Flh-2, And Flh-3 Repress Embryonic Expression Of Microrna Genes In C. Elegans, Maria C. Ow, Natalia Julia Martinez, Philip H. Olsen, Howard S. Silverman, M. Inmaculada Barrasa, Barbara Conradt, Albertha J. M. Walhout, Victor R. Ambros
Victor R. Ambros
MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression post-transcriptionally via antisense base-pairing. Although miRNAs are involved in a variety of important biological functions, little is known about their transcriptional regulation. Using yeast one-hybrid assays, we identified transcription factors with a FLYWCH Zn-finger DNA-binding domain that bind to the promoters of several Caenorhabditis elegans miRNA genes. The products of the flh-1 and flh-2 genes function redundantly to repress embryonic expression of lin-4, mir-48, and mir-241, miRNA genes that are normally expressed only post-embryonically. Although single mutations in either flh-1 or flh-2 genes result in a viable phenotype, double mutation …
A C. Elegans Genome-Scale Microrna Network Contains Composite Feedback Motifs With High Flux Capacity, Natalia Julia Martinez, Maria C. Ow, M. Inmaculada Barrasa, Molly Hammell, Reynaldo Sequerra, Lynn Doucette-Stamm, Frederick P. Roth, Victor R. Ambros, Albertha J. M. Walhout
A C. Elegans Genome-Scale Microrna Network Contains Composite Feedback Motifs With High Flux Capacity, Natalia Julia Martinez, Maria C. Ow, M. Inmaculada Barrasa, Molly Hammell, Reynaldo Sequerra, Lynn Doucette-Stamm, Frederick P. Roth, Victor R. Ambros, Albertha J. M. Walhout
Victor R. Ambros
MicroRNAs (miRNAs) and transcription factors (TFs) are primary metazoan gene regulators. Whereas much attention has focused on finding the targets of both miRNAs and TFs, the transcriptional networks that regulate miRNA expression remain largely unexplored. Here, we present the first genome-scale Caenorhabditis elegans miRNA regulatory network that contains experimentally mapped transcriptional TF --> miRNA interactions, as well as computationally predicted post-transcriptional miRNA --> TF interactions. We find that this integrated miRNA network contains 23 miRNA <--> TF composite feedback loops in which a TF that controls a miRNA is itself regulated by that same miRNA. By rigorous network randomizations, we show …
Generation And Assessment Of Muscular Mutations In Caenorhabditis Elegans, Katie N. Reget
Generation And Assessment Of Muscular Mutations In Caenorhabditis Elegans, Katie N. Reget
DePaul Discoveries
A study of egg laying muscular mutations in C. elegans was conducted over a span of ten weeks. Parent (EGL-19) and wild type (N2) were exposed to mutagenesis and integration mutation techniques to generate genetic and physical different mutants. Overall, four genetic, physical and phenotypically unique worms were generated for the process of mutagenesis. The worms used in the process of integration were found to have shortened life spans, reduced size and decrease numbers of progeny.
Molecular Basis Of Rna Recognition By The Embryonic Polarity Determinant Mex-5, John Pagano, Brian Farley, Lisa Mccoig, Sean Ryder
Molecular Basis Of Rna Recognition By The Embryonic Polarity Determinant Mex-5, John Pagano, Brian Farley, Lisa Mccoig, Sean Ryder
Sean P. Ryder
Embryonic development requires maternal proteins and RNA. In Caenorhabditis elegans, a gradient of CCCH tandem zinc finger (TZF) proteins coordinates axis polarization and germline differentiation. These proteins govern expression from maternal mRNAs by an unknown mechanism. Here we show that the TZF protein MEX-5, a primary anterior determinant, is an RNA-binding protein that recognizes linear RNA sequences with high affinity but low specificity. The minimal binding site is a tract of six or more uridines within a 9-13-nucleotide window. This sequence is remarkably abundant in the 3'-untranslated region of C. elegans transcripts, demonstrating that MEX-5 alone cannot specify mRNA target …
Rna Target Specificity Of The Embryonic Cell Fate Determinant Pos-1, Brian Farley, John Pagano, Sean Ryder
Rna Target Specificity Of The Embryonic Cell Fate Determinant Pos-1, Brian Farley, John Pagano, Sean Ryder
Sean P. Ryder
Specification of Caenorhabditis elegans body axes and cell fates occurs prior to the activation of zygotic transcription. Several CCCH-type tandem zinc finger (TZF) proteins coordinate local activation of quiescent maternal mRNAs after fertilization, leading to asymmetric expression of factors required for patterning. The primary determinant of posterior fate is the TZF protein POS-1. Mutants of pos-1 are maternal effect lethal with a terminal phenotype that includes excess pharyngeal tissue and no endoderm or germline. Here, we delineate the consensus POS-1 recognition element (PRE) required for specific recognition of its target mRNAs. The PRE is necessary but not sufficient to pattern …