Navigation Links
Penn biologists determine microRNA activity is suppressed in mouse ovum

PHILADELPHIA - Biologists at the University of Pennsylvania studying oocytes in mice, the immature egg cells necessary for sexual reproduction, have demonstrated an unusual behavior in microRNA, or miRNA, activity that may be the first event in reprogramming the differentiated oocyte into pluripotent blastomeres of the embryo. MicroRNAs are a member of the family of small RNAs, the so-called dark matter of the biological world.

MicroRNAs imperfectly pair with untranslated regions of RNA and mediate translational repression and mRNA degradationhallmarks of the gene expression process. The Dicer enzyme, which generates small RNAs in the miRNA and RNA interference pathways, is essential for meiotic maturation of mouse oocytes.

The scientists found that the mRNA population in oocytes lacking Dicer was not enriched in miRNA binding sites, implicating a weak impact of miRNAs on regulating mRNA stability. To explore further this possibility, the scientists injected a reporter transcript, a message RNA that is not a normally present in the oocyte but contained sequences that would interact with miRNAs in the oocyte. In somatic cells, such a message would be degraded and suppressed by micro RNA. However, in oocytes, there is minimal translational repression and no degradation of the message. The finding that this pathway does not operate in oocytes is most surprising because miRNAs are implicated in controlling cell differentiation.

The data, according to researchers, presents a puzzling paradox. "Although mouse oocytes produce miRNAs, their mRNA targets are poorly repressed," said Richard Schultz, associate dean for the natural sciences and the Charles and William L. Day Distinguished Professor of Biology in Penn's School of Arts and Sciences. "Reducing miRNA activity during oocyte growth may have two roles. First, the low activity of miRNA-mediated mRNA degradation, perhaps linked to the absence of P bodies (structures that are implicated as sites of miRNA-mediated mRNA degradation) may contribute to mRNA stability and accumulation of mRNA in growing oocytes. Second, down-regulation of the miRNA pathway may be required for oocyte-to-zygote transition."


Contact: Jordan Reese
University of Pennsylvania

Related biology news :

1. CCNY biologists identify new spiny pocket mouse species
2. Penn biologists explain how organisms can tolerate mutations, yet adapt to environmental change
3. Biologists merge methods, results from different disciplines to find new meaning in old data
4. New handbook for biologists who need more competence or confidence in statistics
5. Biologists discover bacterial defense mechanism against aggressive oxygen
6. Beyond genomics, biologists and engineers decode the next frontier
7. Biologists, educators recognize excellence in evolution education
8. NIMBioS hosts tutorial on optimal control and optimization for biologists
9. Biologists discover death stench is a universal ancient warning signal
10. UTSA plant biologists publish where their peers are -- on the Web
11. Microbiologists find defense molecule that senses respiratory viruses
Post Your Comments:
(Date:10/27/2015)... Munich, Germany , ... (ASGM) automatically maps data from mobile eye tracking videos ... so that they can be quantitatively analyzed with SMI,s ... Germany , October 28-29, 2015. SMI,s Automated Semantic ... eye tracking videos created with SMI,s Eye Tracking ...
(Date:10/26/2015)... and LAS VEGAS , Oct. 26, ... , an innovator in modern authentication and a founding ... the launch of its latest version of the Nok ... organizations to use standards-based authentication that supports existing and ... Authentication Suite is ideal for organizations deploying customer-facing applications ...
(Date:10/23/2015)... BERLIN and GOLETA, California ... the HFES conference, BIOPAC and SensoMotoric Instruments (SMI) announce ... and eye tracking data captured during interactive real-world tasks ... plug and play integration of their established wearable solutions ... researchers to synchronize gaze behavior captured with SMI ...
Breaking Biology News(10 mins):
(Date:11/27/2015)... , ... November 27, 2015 , ... ... that includes over 2,000 technical presentations offered in symposia, oral sessions, workshops, ... applied spectroscopy, covers a wide range of applications such as, but not limited ...
(Date:11/25/2015)... 2015  PharmAthene, Inc. (NYSE MKT: PIP) announced  today ... rights plan (Rights Plan) in an effort to preserve ... under Section 382 of the Internal Revenue Code (Code). ... use of its NOLs could be substantially limited if ... Section 382 of the Code. In general, an ownership ...
(Date:11/25/2015)... /PRNewswire/ - Aeterna Zentaris Inc. (NASDAQ:  AEZS; TSX: AEZ) ... remain fundamentally strong and highlights the following developments: ... DSMB recommendation to continue the ZoptEC Phase 3 ... final interim efficacy and safety data , ... with heavily pretreated castration- and Taxane-resistant prostate cancer ...
(Date:11/24/2015)... 24, 2015  Asia-Pacific (APAC) holds the third-largest ... market. The trend of outsourcing to low-cost locations ... higher volume share for the region in the ... margins in the CRO industry will improve. ... ( ), finds that the market earned ...
Breaking Biology Technology: