Featured Research

from universities, journals, and other organizations

Biologists determine microRNA activity is suppressed in mouse ovum

Date:
February 7, 2010
Source:
University of Pennsylvania
Summary:
Scientists studying RNA activity, the so-called dark matter of the biological world, may have found the first event in reprogramming a differentiated oocyte into pluripotent blastomeres of the embryo.

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 degradation -- hallmarks 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."

The study, appearing in the journal Current Biology, was conducted by Schultz, Jun Ma and Paula Stein at Penn; Matyas Flemr, Radek Malik and Petr Svoboda of the Institute of Molecular Genetics, Academy of Sciences of the Czech Republic; and Philipp Berninger and Mihaela Zavolan of the University of Basel and Swiss Institute of Bioinformatics.

The study was funded by the National Institutes of Health, a European Molecular Biology Organization's Strategic Development and Integration Grant and the Purkinje Fellowship.


Story Source:

The above story is based on materials provided by University of Pennsylvania. Note: Materials may be edited for content and length.


Cite This Page:

University of Pennsylvania. "Biologists determine microRNA activity is suppressed in mouse ovum." ScienceDaily. ScienceDaily, 7 February 2010. <www.sciencedaily.com/releases/2010/02/100203131409.htm>.
University of Pennsylvania. (2010, February 7). Biologists determine microRNA activity is suppressed in mouse ovum. ScienceDaily. Retrieved August 27, 2014 from www.sciencedaily.com/releases/2010/02/100203131409.htm
University of Pennsylvania. "Biologists determine microRNA activity is suppressed in mouse ovum." ScienceDaily. www.sciencedaily.com/releases/2010/02/100203131409.htm (accessed August 27, 2014).

Share This




More Plants & Animals News

Wednesday, August 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Super Healthful Fruits and Vegetables: Which Are Best?

Super Healthful Fruits and Vegetables: Which Are Best?

Ivanhoe (Aug. 27, 2014) We all know that it is important to eat our fruits and vegetables but do you know which ones are the best for you? Video provided by Ivanhoe
Powered by NewsLook.com
Bad Memories Turn Good In Weird Mouse Brain Study

Bad Memories Turn Good In Weird Mouse Brain Study

Newsy (Aug. 27, 2014) MIT researchers were able to change whether bad memories in mice made them anxious by flicking an emotional switch in the brain. Video provided by Newsy
Powered by NewsLook.com
Do Couples Who Smoke Weed Together Stay Together?

Do Couples Who Smoke Weed Together Stay Together?

Newsy (Aug. 27, 2014) A study out of University at Buffalo claims couples who smoke marijuana are less likely to experience intimate partner violence. Video provided by Newsy
Powered by NewsLook.com
Panda Might Have Faked Pregnancy To Get Special Treatment

Panda Might Have Faked Pregnancy To Get Special Treatment

Newsy (Aug. 27, 2014) A panda in China showed pregnancy symptoms that disappeared after two months of observation. One theory: Her pseudopregnancy was a ploy for perks. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins