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3

Yes, transcription of a polyA sequence will be unreliable: for a repetition of 15 times the same nucleotide, the rate of transcription errors will be huge. For example in E. coli, this paper http://www.ncbi.nlm.nih.gov/pmc/articles/PMC331007/ gives some order of magnitude of transcription errors caused by repeats of nucleotides. According to their data, for ...


1

Thermo Fisher has a protocol for the separation of host mammalian RNA from prokaryotic RNA, optimized for E. coli vs human, mouse or rat sequences. Capture oligonucleotides bind portions of the mammalian RNA and hybridize. These hybridized oligo/RNA are then removed from solution via "oligonucleotide-derivatized magnetic beads," after which the remaining RNA ...


0

This article suggests RNA Pol III formed early in eukaryote evolution, and while there's a lot of conservation, the enzyme-specific subunits result from divergent evolution. Another article suggests the actual increase of subunits, however, is a result of the permanent recruitment of transcription factors to the core RNAP by studying homology of subunits to ...


0

As many kits suggest, RNA concentration has the most profound influence on precipitation efficiency / recovery fraction. Time, temperature and precipitation agent concentration has lesser effect. See for example instruction by Life Technologies on LiCl precipitation: The Use of LiCl Precipitation for RNA Purification


4

As far as I know this has never been thoroughly analyzed for RNA, but there is an excellent paper on the precipitation of DNA and the usual conditions in BRL Focus by Zeugin (see below for the paper). Since DNA and RNA are pretty much the same (except for one OH-Group) and the conditions used for precipitation are also similar, I think we can use this for a ...


2

The three RNA polymerases (RNAPs) are very similar to each other, yet not identical. As described in this article, there are subunits that are specific for each type of polymerases. In addition to providing unique substrates that polymerase-specific subunits bind to give each of the RNAPs their specific functionality, the two largest subunits also shape ...


0

I wanted to illustrate the process I explained in a comment on aandreev's answer with some images, I just copy/pasted the actual text sections, however. From comments: The tRNA is bound to an elongation EF-Tu (which is also bound to GTP). The Ef-Tu has an affinity for a factor binding site in the A-site of the large ribosomal subunit. You have an anticodon ...


0

As with many processes in cellular biology, nothing really moves anywhere, attracted by specific force. What that means, is that any molecule has a chance to interact with any other molecule, say, bind to it. Only force that is acted is electrical force of attraction of negative charges to positive ones. Due to diffusion and temperature fluctuations, ...


8

A pre-tRNA is transcribed from tRNA genes in DNA by RNA polymerase III. Processing occurs in the nucleus, where a 5' sequence is cleaved by RNase P, the 3's CCA motif is added, and ~10% of the nucleotides are substituted. The tRNA are transported out via the pore complexes. Aminoacyl-tRNA synthetase enzymes attach amino acids in the cytoplasm in a 2-step ...


5

I think it is relatively unlikely that the RNA will degrade under this conditions. For the future, I would handle this differently: You can centrifuge the cells and snap freeze them in an appropriate buffer in liquid nitrogen and then store them at -80°C. I would not freeze the dry pellet, as these are often hard to re-dissolve after freezing. ...



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