The FMI/GMA guidance closely follows the recommendations from NRDC and the Harvard Food Law and Policy Clinic’s landmark 2013 report, "The Dating Game: How Confusing Labels Land Billions of Pounds of Food in the Trash," which brought the issue into the spotlight. Essentially, it does a few key things:
News Article | July 26, 2017
When the French physiologist Étienne-Jules Marey set out to study animal locomotion at the end of the nineteenth century, he needed a novel technology to overcome the limitations of the human eye in visualizing rapid movements. To freeze animal motion, he recorded several phases of movement in a single frame, pioneering what he later termed chronophotography. The resulting pictures of a flying bird, for example, were not only aesthetic, but most importantly helped him to dissect the physiology of motion. Nowadays, molecular biologists face a similar problem when trying to understand gene regulation. Until now, when they looked at the binding of proteins to the genome, they saw thousands of binding events overlaid in a blurry picture. Now, Dirk Schübeler and his group at the FMI have developed a high-resolution method whereby different phases of gene expression can be detected. First author and SNSF Ambizione Fellow Arnaud Krebs explains: "For the first time, we're able to look at the binding of proteins regulating transcription on individual DNA molecules. Based on this, we can study the steps of the transcriptional process one by one, similar to how Marey separated the different phases of movement in one picture." But how does this help to understand how genes are activated or repressed? To transcribe a particular gene, transcription factors recognize and bind to certain DNA sequences, and recruit RNA polymerase II, which in turn initiates RNA synthesis. Before producing the full transcript, the polymerase pauses briefly to control the quality of the transcript. Interestingly, for some genes this pause is extended and RNA synthesis is thus blocked. It had been thought that this pause could be a means of loading a pool of polymerases to enable fast activation of genes that require rapid induction, such as those involved in the response to stress. However, using their new method to directly probe RNA polymerases on DNA, the FMI team realized that - rather than being stably paused - the polymerases frequently terminate transcription prematurely. According to Krebs, they observed that a large fraction of the RNA polymerases dissociates from the DNA. As Schübeler explains, these findings refine the prevalent concept of pausing: "What we see rather suggests a mechanism involving high RNA polymerase II turnover at these genes. While this is mechanistically different from the prevalent concept, the , the new model similarly allows for rapid activation of genes upon stimuli." The FMI scientists were thus not only able to quantify protein binding at single-molecule resolution, but also gained a better understanding of transcription initiation - and new mechanistic insights into gene regulation. Explore further: Polymerases pause to help mediate the flow of genetic information More information: Arnaud R. Krebs et al. Genome-wide Single-Molecule Footprinting Reveals High RNA Polymerase II Turnover at Paused Promoters, Molecular Cell (2017). DOI: 10.1016/j.molcel.2017.06.027
News Article | June 5, 2017
Control of RNA lifespan is vital for the proper functioning of our cells. Marc Bühler's group at the Friedrich Miescher Institute for Biomedical Research (FMI) has discovered a novel mechanism determining the fate of RNA in mammalian cells: two proteins involved in RNA interference - Dgcr8 and Drosha - together with a methyltransferase, Mettl3, mark nascent RNAs for degradation as they are transcribed. This mechanism allows RNA transcripts to "remember" the conditions under which they were synthesized. Life of an RNA is never easygoing. Its formation, processing, lifespan and degradation are all tightly regulated. This stringent control of RNA metabolism ensures that genes become active at the right time and place, safeguarding cell functions. In this context, a control mechanism known as RNA interference (RNAi) has attracted a lot of attention. RNAi leads to the fragmentation and inactivation of RNAs in the cytoplasm. Interestingly, in yeast, the RNAi machinery is also active in the nucleus: during RNA synthesis, while the RNA molecules still associate with the DNA, it triggers the degradation of nascent RNAs. Whether the RNAi machinery plays a similar role in mammalian cells has remained unclear. To address this question, Marc Bühler and his group at the FMI used mouse embryonic stem cells. Bühler comments: "This is a good example of how knowledge gained in a model organism – here in fission yeast – guides our hypotheses and informs our experiments in higher organisms." In their study, published in Nature Structural & Molecular Biology, the scientists showed that two well known mammalian RNAi factors interact with chromatin: both Dgcr8 (an RNA-binding protein) and Drosha (an RNase) bind to nascent transcripts, thereby silencing genes co-transcriptionally. First author Philip Knuckles, an NCCR-funded postdoctoral fellow in Bühler's lab, explains: "In multicellular organisms, Dgcr8 and Drosha form a complex called the microprocessor (MP). This complex does not exist in yeast, but our results suggest that it takes over the function of the yeast RNAi protein Dicer. The principle is conserved, but the players differ slightly." The FMI scientists also showed that an enzyme known as Mettl3 is involved in the degradation of nascent RNAs. Mettl3 transfers methyl groups to adenosine residues in RNA, a mark that also influences RNA stability. Knuckles says: "In our experiments, we showed that Mettl3 binds to chromatin while RNA is being transcribed, and that this Mettl3 association stimulates Dgcr8 binding." The MP/Mettl3 system allows the cell to react rapidly to changing growth conditions. Bühler explains: "During a stress situation induced by high temperature, the heat-shock RNA transcripts produced are concomitantly tagged by adenosine methylation. This marks these RNAs for subsequent degradation, enabling a swift but time-limited response to stress." According to Bühler, both the fast stress response and the rapid clearance of heat-shock transcripts and proteins are important for cells: "The accumulation of stress response proteins is detrimental to the cell and is often observed in cancer. Explore further: Small RNAs interact with newly synthesized transcripts to silence chromatin More information: RNA fate determination through cotranscriptional adenosine methylation and microprocessor binding. Nat Struct Mol Biol. nature.com/articles/doi:10.1038/nsmb.3419
News Article | February 17, 2017
The label "sell by" on food items has been the cause of major confusion among buyers for a long time, given that no one can tell for certain what the label means. However, the grocery industry has finally taken steps to clear up matter for most American citizens. On Feb. 15, the two largest trade groups of the grocery industry - the Food Marketing Institute (FMI) and the Grocery Manufacturers Association (GMA) made an announcement to do away with the "sell by" tag. Per the Standardized Voluntary Regulations, stated by the two trade groups of the grocery industry, every manufacturer will be now be using only two labels- "use by" and "best if used by", instead of the other 10 labels used earlier. The "use by" label acts as the safety indicator, thus hinting to the customer the date by which the food is safe to eat and when it is not. The "best if used by" label acts as description of quality by the manufacturer, which hints when the product should be consumed to get the best taste. These dates, which will come from the manufacturer, actually points to one of the two - either the dates indicated to the store when the product should be stacked on store shelves, or suggest to the consumers when to consume the food item for best taste. Environmental groups and the Department of Agriculture, have been for a long time coaxing the food industry to clear this mess up as soon as possible. "I think it's huge. It's just an enormous step," said Emily Broad-Leib, director of Harvard's Food Law and Policy Clinic. Although some of the states have food labeling regulations, most of the major retailers like Walmart have supported the move and have already started abiding by the new regulation. The FMI and GMA are urging other retailers and manufacturers to adopt the policy as soon as possible. However, they have until July 2018 to incorporate the changes. Moreover, the standards adopted by the FMI and GMA are voluntary and it necessarily doesn't guarantee the fact that all retailers and manufacturers will adopt the change. Despite this fact, both FMI and GMA expect to widespread adoption of the policy change as the standards were jotted down by a working group having representatives from large food companies. According to Walmart, who has already started implementing the change, the new labels will clear up any confusion that the buyer may have in his or her mind and will also reduce food waste. Natural Resources Defense Council states that many Americans are throwing out consumable food thinking that it has gone past its expiry date. "Clarifying and standardizing date label language is one of the most cost effective ways that we can reduce the 40 percent of food that goes to waste each year in the United States," noted Leib. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
News Article | February 21, 2017
In a bid to reduce food waste, two major industry associations have released new guidance to clarify food expiration dates.