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The inclusion of formaldehyde in the gel and buffer is to keep the RNA denatured (ie after heating the sample to melt the double-stranded stem-loops, just prior to loading the gel), in the hope that the RNA will migrate through the gel with an Rf proportional to its molecular weight (approximated here by its length). Therefore the correct size markers would ...


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Transcription interference can also be a good mechanism to provide such switches. Transcription interference occurs between genes in close adjacency to each other. This is basically, as the term suggest, that the neighbouring genes can interfere with each others transcription (by overlapping promoters blocking transcription initiation, collision of ...


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Positive feedbacks can be one alternative. Positive feedbacks exhibit bistability and can therefore adopt one of the two stable states depending on the initial condition. A famous example of a positive feedback switch would be that between cI and Cro in λ-phage, which repress each other. Positive feedbacks also display hysteresis: if the state of the system ...


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Yes, these sequences exist and they are called "silencers" (surprising, right?). There are different mechanisms by which this silencing of genes can happen. In the "classical" way the silencer is bound by a transcription factor which either passively suppress the gene by hindering the binding of specific transcription factors or by actively preventing the ...


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I found a great article that might help. To summarize the contents of the article, there are two classes of CAP dependent promoters/genes, and the distance of the CAP bindings site in these classes are different. Also the actions in which CAP is involved are different in the two classes of promoters. In the first class it does not overlap with the promoter ...


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MicroRNA (miRNA) are gene-regulatory RNAs that are loaded onto the RNA-induced silencing complex (RISC) and interact with partially-complementary targets on mRNA to suppress protein expression. The miRNA is originally double-stranded and composed of strands about 21 nucleotides long; on loading onto RISC, one strand is degraded and the other, the "guide" ...


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21joanna12, look into snRNPs. These are parts of the splicosomal apparatus and some of them (the U1 and U2, U11 and U12 snRNPs) are also the guideposts that bind near the splice junctions at the end of introns. These help guide the splicing apparatus to the splice sites. There are also proteins that bind RNA and interact with the splicing apparatus to ...


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Short answer: Yes, you can. Usually these are coupled systems for transcription and translation. For these you clone the gene of interest into a vector which contains a prokaryotic promoter which is then used to generate the mRNA in the tube. This mRNA is then translated in the second step into a protein. This works very well, but the protein is missing ...


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The pattern we see in B. subtilis is quite common in prokaryotes. The origin of replication is shown at the top of the genome diagram. DNA replication proceeds bidirectionally from this point. In the B. subtilis diagram, most genes are located along the leading strand in each direction. Even in E. coli, by the way, important genes, including all rRNAs, tend ...


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Addition to the previous answer. How to express channelrhodopsins in neurons? Other than the method involving direct viral injection, as described in the previous answer, these proteins can be expressed in specific cells by making transgenics (by using promoters that will express the downstream gene in only specific cells). How does it work? When ...


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Short answer Optogenetics can be used to make cells responsive to light. One striking use of this technology is to restore vision in the blind by making the surviving neurons in the retina light-sensitive. This can be done by transfecting the retina with genetically engineered viruses that induce the expression of bacterial channelrhodopsin proteins in ...


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I can't fault @WYSIWYG for mentioning the cited Vogelstein article in providing an answer. You point to what seems like a great explanation for why certain cancers arise in some tissues but not others. However, for those who look closely this paper has some serious errors in its derivation of the model, and for good reason it has come under strong fire in ...


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You should have a look at this interesting article published earlier this year in Science. There are two mechanisms by which cells can accumulate mutations in DNA: Replication errors External physicochemical agents such as UV, carcinogens etc In the abovementioned paper, the authors classify cancers into two types: That arise predominantly because of ...


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In RNA sequencing, the RNA is fragmented, DNA is synthesized complementary to the RNA fragments, which is followed by a complementary strand synthesis. Fragmentation can be done after the cDNA synthesis too. This DNA is then amplified to form a cluster that is sequenced. Most Next-Gen sequencing approaches sequence a short segment of the DNA (it has ...


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Broadly speaking there are two classes of cell in an organism: Somatic cells These are by far the most numerous in your body, and are the differentiated cells including everything from retinal cells to liver cells to neurons. Stem cells and germ cells Stem cells reside in tissues and replenish the somatic cells as they are damaged or removed, or as ...


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This question can't be answered with a simple yes/no, but I would say that the analogy of DNA being the "code" used by cells is a reasonable one, if taken with a number of other considerations. DNA function When Watson and Crick first described the structure of DNA (being a double-stranded sequence of the nucleotides Adenine, Cytosine, Guanine and ...



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