scholarly journals P-bodies and the miRNA pathway regulate translational repression of bicoid mRNA during Drosophila melanogaster oogenesis

2018 ◽  
Author(s):  
John M. McLaughlin ◽  
Daniel F.Q. Smith ◽  
Irina E. Catrina ◽  
Diana P. Bratu

ABSTRACTEmbryonic axis patterning in Drosophila melanogaster is partly achieved by mRNAs that are maternally localized to the oocyte; the spatio-temporal regulation of these transcripts’ stability and translation is a characteristic feature of oogenesis. While protein regulatory factors are necessary for the translational regulation of some maternal transcripts (e.g. oskar and gurken), small RNA pathways are also known to regulate mRNA stability and translation in eukaryotes. MicroRNAs (miRNAs) are small RNA regulators of gene expression, widely conserved throughout eukaryotic genomes and essential for animal development. The main D. melanogaster anterior determinant, bicoid, is maternally transcribed, but it is not translated until early embryogenesis. We investigated the possibility that its translational repression during oogenesis is mediated by miRNA activity. We found that the bicoid 3’UTR contains a highly conserved, predicted binding site for miR-305. Our studies reveal that miR-305 regulates the translation of a reporter gene containing the bicoid 3’UTR in cell culture, and that miR-305 only partially contributes to bicoid mRNA translational repression during oogenesis. We also found that Processing bodies (P-bodies) in the egg chamber may play a role in stabilizing bicoid and other maternal transcripts. Here, we offer insights into the possible role of P-bodies and the miRNA pathway in the translational repression of bicoid mRNA during oogenesis.

2012 ◽  
Vol 198 (4) ◽  
pp. 529-544 ◽  
Author(s):  
Virginia Castilla-Llorente ◽  
Lee Spraggon ◽  
Miwako Okamura ◽  
Saif Naseeruddin ◽  
Matthew Adamow ◽  
...  

The microRNA (miRNA)-induced silencing complex (miRISC) controls gene expression by a posttranscriptional mechanism involving translational repression and/or promoting messenger RNA (mRNA) deadenylation and degradation. The GW182/TNRC6 (GW) family proteins are core components of the miRISC and are essential for miRNA function. We show that mammalian GW proteins have distinctive functions in the miRNA pathway, with GW220/TNGW1 being essential for the formation of GW/P bodies containing the miRISC. miRISC aggregation and formation of GW/P bodies sequestered and stabilized translationally repressed target mRNA. Depletion of GW220 led to the loss of GW/P bodies and destabilization of miRNA-targeted mRNA. These findings support a model in which the cellular localization of the miRISC regulates the fate of the target mRNA.


2007 ◽  
Vol 304 (1) ◽  
pp. 62-74 ◽  
Author(s):  
Laure Guenin ◽  
Yaël Grosjean ◽  
Stéphane Fraichard ◽  
Angel Acebes ◽  
Fawzia Baba-Aissa ◽  
...  

2021 ◽  
Vol 28 ◽  
pp. 101162
Author(s):  
Kun Zhang ◽  
Melissa M. Cremers ◽  
Stephan Wiedemann ◽  
David M. Poitz ◽  
Christian Pfluecke ◽  
...  

2021 ◽  
Author(s):  
Juan Manuel Crescente ◽  
Diego Zavallo ◽  
Mariana del Vas ◽  
Sebastian Asurmendi ◽  
Marcelo Helguera ◽  
...  

Abstract Plant microRNAs (miRNAs) are a class of small non-coding RNAs that are 20–24 nucleotides length and can repress gene expression at post-transcriptional levels by target degradation or translational repression. There is increasing evidence that some microRNAs can be derived from a group of non-autonomous class II transposable elements called Miniature Inverted-repeat Transposable Elements (MITEs) in plants. We used public small RNA, degradome libraries and the common wheat (Triticum aestivum) genome to screen miRNAs production and target sites. We also created a comprehensive wheat MITE database using known and identifying novel elements. We found high homology between MITEs and 14% of all the miRNAs production sites in wheat. Furthermore, we show that MITE-derived miRNAs have preference for target degradation sites with MITE insertions in 3' UTR regions in wheat.


2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Sahar A Basir ◽  
Tiffany Asante ◽  
Khosrow Adeli

Hepatic apolipoprotein B-100 (apoB) synthesis and secretion appears to be regulated largely at the posttranscriptional and posttranslational levels. MicroRNAs (miRNAs) are among posttranscriptional regulators of gene expression that bind to complementary sequences on target messenger RNA (mRNA) transcripts, usually resulting in translational repression or degradation. It is unknown whether specific miRNAs are involved in posttranscriptional regulation of apoB mRNA. We performed bioinformatic analysis, showing that two specific miRNAs with satisfactory E-values level (with levels indicating greater similarity between the input and its match) namely, miR-544 (E-value = 0.91) and miR-1202 (E-value=0.86) have potential to interact with 3’ and 5’ UTR of apoB, respectively. We hypothesized that the interaction of these specific miRNAs (miR-544 and miR-1202) with the 3’ and 5’UTR of apoB mRNA leads to apoB mRNA translational repression and/or activation. Using a human hepatoma cell line model, HepG2, the effects of overexpressed miRNAs and inhibition of endogenous miRNAs on the expression of apoB mRNA and apoB protein synthesis were investigated. We further examined the effect of these miRNAs on apoB mRNA traffic into cytoplasmic P-bodies. Transfection of HepG2 cells with miR-544 led to a significant reduction in apoB mRNA expression and protein synthesis and induced an increase in the co-localization of apoB mRNA into P-bodies. The opposite effect was observed when anti-miR-544 was employed to inhibit the endogenous miR-544. Results from luciferase reporter assays indicated that the effects of miR-544 may be mediated via interaction with the 3’UTR of apoB mRNA. In contrast to miR-544, miR-1202 overexpression induced an increase in apoB mRNA expression and protein synthesis. Similarly, the opposite effect was observed when using anti-miR-1202. Data from luciferase reporter assays showed an increased expression of the reporter gene in constructs carrying 5’UTR of apoB mRNA suggesting that miR-1202 may function via the 5’UTR. In summary, these data demonstrate that specific miRNAs are involved in the regulation of expression and translational control of apoB mRNA in hepatocytes. However, these miRNAs do not appear to mediate insulin regulation.


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