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Thread: Interesting Medical News (Non-WCG Related Projects) |
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Thread Status: Active Total posts in this thread: 377
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twilyth
Master Cruncher US Joined: Mar 30, 2007 Post Count: 2130 Status: Offline Project Badges: 
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mRNA is the fully spliced mature form of RNA containing 5' and 3' untranslated regions, a chemically modified 5' end, and the coding sequence. miRNA's can be detected in the cytoplasm and the nucleus. I think you meant to say RNAi or siRNA.   |
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yojimbo197
Advanced Cruncher Joined: Jun 30, 2012 Post Count: 83 Status: Offline Project Badges: 
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Nope.
----------------------------------------miRNA: http://en.wikipedia.org/wiki/MicroRNA A microRNA (abbr. miRNA) is a small non-coding RNA molecule (ca. 22 nucleotides) found in plants and animals, which functions in transcriptional and post-transcriptional regulation of gene expression. Encoded by eukaryotic nuclear DNA, miRNAs function via base-pairing with complementary sequences within mRNA molecules, usually resulting in gene silencing via translational repression or target degradation. siRNA: http://en.wikipedia.org/wiki/Small_interfering_RNA siRNAs have a well-defined structure: a short (usually 21-bp) double-stranded RNA (dsRNA) with phosphorylated 5' ends and hydroxylated 3' ends with two overhanging nucleotides. The Dicer enzyme catalyzes production of siRNAs from long dsRNAs and small hairpin RNAs.  [Edit 1 times, last edit by yojimbo197 at Feb 9, 2013 8:36:23 AM] |
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twilyth
Master Cruncher US Joined: Mar 30, 2007 Post Count: 2130 Status: Offline Project Badges:
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What I meant was, RNAi would be the generic for both if you were going to over look siRNA
----------------------------------------Two types of small ribonucleic acid (RNA) molecules – microRNA (miRNA) and small interfering RNA (siRNA) – are central to RNA interference. |
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yojimbo197
Advanced Cruncher Joined: Jun 30, 2012 Post Count: 83 Status: Offline Project Badges:
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RNAi is a general term encompassing the effects of miRNA and siRNA.
----------------------------------------However miRNA is different from siRNA. miRNA's are genetically encoded while siRNA's are derived from longer dsRNA molecules and shRNA's. |
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twilyth
Master Cruncher US Joined: Mar 30, 2007 Post Count: 2130 Status: Offline Project Badges:
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Yes, I know that they're different, that's why I pointed out the fact that you over looked one. And while shRNA's may be exogenous, dsRNA's are, or at least can be, genetic.
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yojimbo197
Advanced Cruncher Joined: Jun 30, 2012 Post Count: 83 Status: Offline Project Badges:
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I didn't overlook siRNA. I merely stated what I knew to be true regarding miRNA subcellular locatlization based on current literature. You presumed that I meant siRNA or RNAi.
----------------------------------------In doing some digging into the literature regarding siRNA, it appears that siRNA's can also localize to either the cytoplasm or the nucleus. This localization may depend on the target of siRNA. As fas as dsRNA is concerned, while there are dsRNA viruses. there are not stabile dsRNA's genetically encoded in mammalian cells(that are known to date). In fact there are dsRNA binding proteins that will trigger signaling pathways leading to inflammatory gene production, eg interferon that lead to an innate immune response. [Edit 2 times, last edit by yojimbo197 at Feb 9, 2013 10:12:47 AM] |
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twilyth
Master Cruncher US Joined: Mar 30, 2007 Post Count: 2130 Status: Offline Project Badges:
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We were talking about RNA interference and siRNA is one of the mechanism - or do you dispute that?
----------------------------------------As to the other point, I'm afraid you'll have to rethink tha t In mammals, where no RdRP activity has been found, biogenesis and function of endogenous siRNAs remain largely unknown. Here we show, using mouse oocytes, that endogenous siRNAs are derived from naturally occurring dsRNAs and have roles in the regulation of gene expression. By means of deep sequencing, we identify a large number of both approximately 25-27-nucleotide Piwi-interacting RNAs (piRNAs) and approximately 21-nucleotide siRNAs corresponding to messenger RNAs or retrotransposons in growing oocytes. piRNAs are bound to Mili and have a role in the regulation of retrotransposons. siRNAs are exclusively mapped to retrotransposons or other genomic regions that produce transcripts capable of forming dsRNA structures. Inverted repeat structures, bidirectional transcription and antisense transcripts from various loci are sources of the dsRNAs. Some precursor transcripts of siRNAs are derived from expressed pseudogenes, indicating that one role of pseudogenes is to adjust the level of the founding source mRNA through RNAi. |
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yojimbo197
Advanced Cruncher Joined: Jun 30, 2012 Post Count: 83 Status: Offline Project Badges:
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Again, I mentioned miRNA's because I knew more about them than siRNA's. I did not and have not disputed that they exist. You are the one that presumed that I meant siRNA's. Read your previous post please.
----------------------------------------Regarding dsRNA, that article does not support stabile dsRNA species. piRNA's are not stabile dsRNA species but in fact another sort of RNAi. Furthermore, if you actually read the article, you can see that one source of the dsRNA elements that formed were a result of small RNA species from opposing oriented RNA transcripts that bound to each other intermolecularly as seen in the Pdzd11/Kif4 locus. In addition, A pseudogene present on Chromosome 8 can express siRNA's that are anti-sense to the the exons of Ppp4r1 sequence, which is expressed from Chromosome 17. There was also some mention of siRNA's produced from intramolecular dsRNA's encoded within the sequence of RLTR10. [Edit 2 times, last edit by yojimbo197 at Feb 9, 2013 12:35:33 PM] |
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twilyth
Master Cruncher US Joined: Mar 30, 2007 Post Count: 2130 Status: Offline Project Badges:
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Again, I mentioned miRNA's because I knew more about them than siRNA's. I did not and have not disputed that they exist. You are the one that presumed that I meant siRNA's. Read your previous post please. Yes, and you should read mine. I've already explained myself once so I don't imagine a second attempt will do much good. Regarding dsRNA: I did say "stabile dsRNA's". piRNA's are not stabile but in fact another sort of RNAi. Are you sure you know what you're talking about. You're implying that the siRNA's are derived from piRNA's when the 2 are well know to be completely separate classes. It remains unclear how piRNAs are generated, but potential methods have been suggested, and it is certain their biogenesis pathway is distinct from miRNA and siRNA, while rasiRNAs are a piRNA subspecies.[4] |
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
Can we please limit this thread to just reporting on medical news. Plz take debate to separate thread.
Thx. P.S. No research needed, but it was done and wasted research dollar budgets anyhow [but to learn what protein got affected, and of course to make an expensive medicine]: Green Tea + Red Wine is a strong preventor of Alzheimer, or freezing it in it's track of progression. Flashed by all over the place in popular news, syndicated: https://www.google.it/search?q=green+tea+and+Red+Wine+alzheimer |
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