On Thursday, September 22, 2011 5:11:46 PM UTC-7, Jonathan Cline wrote:
A road to genetic self-regulation?
http://www.nature.com/cr/journal/vaop/ncurrent/pdf/ cr2011158a.pdf
Exogenous plant MIR168a specifically targets mammalian
LDLRAP1: evidence of cross-kingdom regulation by microRNA
doi:10.1038/cr.2011.158
Received 11 August 2011; revised 23 August 2011; accepted 26 August
2011
Chen-Yu Zhang, Jiangsu Engineering Research Center for microRNA
Biology and Biotechnology, State Key Laboratory of Pharmaceutical
Biotechnology,
School of Life Sciences, Nanjing University, 22 Hankou Road, Nanjing
210093, China
Our previous studies have demonstrated that stable microRNAs (miRNAs)
in mammalian serum and plasma are
actively secreted from tissues and cells and can serve as a novel
class of biomarkers for diseases, and act as signaling
molecules in intercellular communication. Here, we report the
surprising finding that exogenous plant miRNAs are
present in the sera and tissues of various animals and that these
exogenous plant miRNAs are primarily acquired
orally, through food intake.
Monsanto has a critique of the above paper, refuting it's conclusion (and coincidentally reenforcing Monsanto's belief in it's genetically modified foods' safety):
https://www.monsanto.com/files/Pages/zhang.aspx
"""
Technical Analysis: Zhang et al.
Monsanto Company
1/10/2012
Zhang et al. (2011) demonstrate that, among the very large number of microRNAs (miRNAs) in plants, a small number can be detected in human and animal blood. In mice, the authors show that following ingestion of large doses of one particular miRNA (MIR168a), MIR168a was absorbed, was detectable in the serum and liver, protein from a particular gene (LDLRAP1) involved in the removal of LDL ("bad") cholesterol from blood was reduced and as a result, LDL levels in the mice were increased.
The authors suggest that such a "cross-kingdom" effect – a plant gene product (MIR168a) regulating animal gene expression – may be a common phenomenon; and that miRNAs in food may regulate specific genes in animals based upon matching sequences between plant miRNAs and mammalian genes.
Since this paper was published, Monsanto scientists have thoroughly studied the work and its relevance to the safety assessment of genetically modified (GM) crops and foods derived from them.
There is too little experimental evidence to conclude that the regulation of animal genes by plant miRNAs is an important diet-mediated phenomenon.....
- After a careful examination of the paper, we have identified a number of relevant facts that should be taken into account when looking at data and the relevancy of the findings.
- Of the many thousands of plant miRNAs, only a small number are found in human or animal blood.
- The absence of most plant miRNAs in serum indicates:
- Absorption may be selective;
- Only some miRNAs in foods have properties which allow them to survive in foods, the GI tract, and serum;
- Only relatively abundant miRNAs are present at high enough levels to be detected;
- Or some combination of these factors.
...
There is a broad foundation of evidence that supports the safety of GM crops that express siRNAs. These data have been reviewed and accepted by Regulatory authorities globally. Monsanto will continue to examine all new evidence published in the scientific literature and our own studies. We are committed to the safety of our products and to safety of the food and feed products produced from them.
"""
## Jonathan Cline
## jcline@ieee.org
## Mobile: +1-805-617-0223
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