Project description:In animals, microRNAs frequently form families with related sequences. The functional relevance of miRNA families and the relative contribution of family members to target repression have remained, however, largely unexplored. Here, we used the C. elegans miR-58 miRNA family, comprised primarily of four highly abundant members: miR-58.1, miR-80, miR-81 and miR-82, as a model to investigate the redundancy of miRNA family members and their impact on target expression in an in vivo setting. RNA was extracted from different miR-58 family mutants (mir-58.1, mir-80; mir-58.1 and mir-80; mir-58.1; mir-81-82) and wild-type Bristol C. elegans strain at late L4 stage and submitted to transcriptome sequencing with Illumina HiSeq2000. The goal was to compare miR-58 target RNA expression and system-wide perturbations across various samples.
Project description:In animals, microRNAs frequently form families with related sequences. The functional relevance of miRNA families and the relative contribution of family members to target repression have remained, however, largely unexplored. Here, we used the C. elegans miR-58 miRNA family, comprised primarily of four highly abundant members: miR-58.1, miR-80, miR-81 and miR-82, as a model to investigate the redundancy of miRNA family members and their impact on target expression in an in vivo setting. RNA was extracted from different miR-58 family mutants (mir-58.1, mir-80; mir-58.1 and mir-80; mir-58.1; mir-81-82) and wild-type Bristol C. elegans strain at late L4 stage and submitted to small RNA profiling with Illumina HiSeq2000. The goal was to see whether miR-58 family members can compensate each other's expression.
Project description:In animals, microRNAs frequently form families with related sequences. The functional relevance of miRNA families and the relative contribution of family members to target repression have remained, however, largely unexplored. Here, we used the C. elegans miR-58 miRNA family, comprised primarily of four highly abundant members: miR-58.1, miR-80, miR-81 and miR-82, as a model to investigate the redundancy of miRNA family members and their impact on target expression in an in vivo setting.
Project description:In animals, microRNAs frequently form families with related sequences. The functional relevance of miRNA families and the relative contribution of family members to target repression have remained, however, largely unexplored. Here, we used the C. elegans miR-58 miRNA family, comprised primarily of four highly abundant members: miR-58.1, miR-80, miR-81 and miR-82, as a model to investigate the redundancy of miRNA family members and their impact on target expression in an in vivo setting.
Project description:Schmitz2014 - RNA triplex formation
The model is parameterized using the
parameters for gene CCDC3 from Supplementary Table S1. The two
miRNAs which form the triplex together with CCDC3 are miR-551b and
miR-138.
This model is described in the article:
Cooperative gene regulation
by microRNA pairs and their identification using a
computational workflow.
Schmitz U, Lai X, Winter F,
Wolkenhauer O, Vera J, Gupta SK.
Nucleic Acids Res. 2014 Jul; 42(12):
7539-7552
Abstract:
MicroRNAs (miRNAs) are an integral part of gene regulation
at the post-transcriptional level. Recently, it has been shown
that pairs of miRNAs can repress the translation of a target
mRNA in a cooperative manner, which leads to an enhanced
effectiveness and specificity in target repression. However, it
remains unclear which miRNA pairs can synergize and which genes
are target of cooperative miRNA regulation. In this paper, we
present a computational workflow for the prediction and
analysis of cooperating miRNAs and their mutual target genes,
which we refer to as RNA triplexes. The workflow integrates
methods of miRNA target prediction; triplex structure analysis;
molecular dynamics simulations and mathematical modeling for a
reliable prediction of functional RNA triplexes and target
repression efficiency. In a case study we analyzed the human
genome and identified several thousand targets of cooperative
gene regulation. Our results suggest that miRNA cooperativity
is a frequent mechanism for an enhanced target repression by
pairs of miRNAs facilitating distinctive and fine-tuned target
gene expression patterns. Human RNA triplexes predicted and
characterized in this study are organized in a web resource at
www.sbi.uni-rostock.de/triplexrna/.
This model is hosted on
BioModels Database
and identified by:
BIOMD0000000530.
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To the extent possible under law, all copyright and related or
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Project description:To discover new miRNA targets, we generated a C. elegans transgenic line expressing a functional N-terminally Tandem Affinity Purification (TAP) tagged ALG-1 protein (C. elegans strain WS4303). We crossed the TAP::ALG-1 transgene into the mir-58(n4640) mutant background to generate the strain WS5041. For simplicity, we will hereafter term the TAP::ALG-1 transgenic animals as wild typeand the transgenic WS5041 animals as mir-58. We compared the mRNA population that coimmunopurified with TAP::ALG-1 from synchronized L4 stage wild-type animals with that from synchronized L4 stage mir-58 mutant animals by one-color Affymetrix gene arrays. miR-58 target mRNAs should be specifically underrepresented in the latter samples.
Project description:Posttranscriptional repression by microRNA (miRNA) occurs through transcript destabilization or translation inhibition. Whereas RNA degradation explains most miRNA-dependent repression, transcript decay occurs co-translationally, raising questions regarding the requirement of target translation to miRNA-dependent transcript destabilization. To assess the contribution of translation to miRNA-mediated RNA destabilization, we decoupled these two molecular processes by dissecting the impact of miRNA loss of function on cytosolic long noncoding RNAs (lncRNAs). We show, that despite interacting with miRNA loaded RNA-induced silencing complex (miRISC), the steady state abundance and degradation rates of these endogenously expressed non-translated transcripts are minimally impacted by miRNA loss. To validate the requirement of translation to miRNA-dependent decay, we fused a miRISC bound lncRNA, whose levels are unaffected by miRNAs, to the 3’end of a protein-coding gene reporter and shown that this results in its miRNA-dependent transcript destabilization. Furthermore, analysis of the few lncRNAs whose levels are regulated by miRNAs revealed these tend to associate with translating ribosomes and are likely misannotated micropeptides, further substantiating the necessity of target translation to miRNA-dependent transcript decay. Our analyses revealed the strict requirement of translation for miRNA-dependent transcript destabilization and demonstrates that the levels of coding and noncoding transcripts are differently affected by miRNAs.
Project description:Gene expression in early animal embryogenesis is in large part controlled post-transcriptionally. Maternally-contributed microRNAs may therefore play important roles in early development. We have elucidated a major biological role of the nematode mir-35 family of maternally-contributed, essential microRNAs. We show that this microRNA family regulates the sex determination pathway at multiple levels, acting both upstream and downstream of her-1 to prevent aberrantly activated male developmental programs in hermaphrodite embryos. The predicted target genes that act downstream of the mir-35 family in this process, sup-26 and nhl-2, both encode RNA binding proteins, thus delineating a previously unknown post-transcriptional regulatory subnetwork within the well-studied sex determination pathway of C. elegans. Repression of nhl-2 by the mir-35 family is not only required for proper sex determination but also for viability, showing that a single microRNA target site can be essential. Since sex determination in C. elegans requires zygotic gene expression to read the sex chromosome karyotype, early embryos must remain gender-naïve; our findings show that the mir-35 family microRNAs act in the early embryo to function as a developmental timer that preserves naïveté and prevents premature deleterious developmental decisions. The mir-35 family of microRNAs is essential for development. The mir-35-41(nDf50) allele deleted 7 of 8 mir-35 family members, and presents a hypomorphic phenotype in which embryonic lethality is temperature sensitive. To characterize the molecular phenotype associated with loss of mir-35 family function, we profiled gene expression in mir-35-41(nDf50) mutant embryos at both permissive (20) and restrictive (25) temperatures. (Refer to A microRNA family exerts maternal control on sex determination in C. elegans)