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12

I don't have any literature to back this up but I doubt that it occurs (at least frequently). For example, imagine a simple three exon gene. Upon splicing exon 1 to exon 3, exon 2 would be excised as part of the intron lariat and subsequently degraded. So in order for exon 2 to be spliced to exon three you would need to either have splicing between exon ...


11

After performing a quick literature search, I am, as with GWW, unable to provide any literature against this occurring, although this paper by Black (2005) states that exons in multi-exon pre-mRNAs are always maintained in order. Black DL. 2005. A simple answer for a splicing conundrum. Proceedings of the National Academy of Sciences of the United States ...


8

You should check out Howald C, et al[1]. This is one of the many recent papers tied to the ENCODE data. They've used RT-PCR to amplify exon-exon junctions and then sequenced the results. Supplemental table 2 shows 3076 validated exon-exon junctions in putative processed transcripts which, in the main body of the paper may be sub-classified as: ...


8

Concerning the first question, it is very well possible to alter human genetics by injecting a highly radio-active substance that will eventually cause mutations almost all cells. The lifespan will be dramatically reduced, however and the condition is known as "radiation sickness"(link to Wikipedia). But the person probably means so-called "directed ...


8

I think the above values (500-750 kb) are wrong. http://www.bioinfo.de/isb/2004040032/ shows that most introns are less than about 10 kb (and personal experience in Drosophila confirms that - I've rarely seen an intron bigger than about 5 kb). There are some very large ones, but since it's nearly impossible to detect the splicing reaction, particularly if ...


7

First of all it is important to note that, within certain limits, human DNA is not much different than, say, a mouse DNA: it has the same structure, it is constituted by the same bases etc etc. Therefore it is teorethically possible (leaving aside ethical issues, of course) to selectively modify it as you would do for a mouse. There are, however, some ...


7

According to literature, histone marks seem to be affecting splicing both directly and indirectly.  The indirect regulation appears to be due to biophysical hindrance, where a certain chromatin structure would cause Pol-II slowdown, allowing the splicing machinery to do its job.  The direct regulation seems to be essentially dependent on H3K36me3 and ...


6

If you examine the human genome ~99% of the introns are under 500 kb. I would assume that a limit between 250 kb - 500 kb is reasonable for gene prediction. You may incorrectly predict the proper structure of a small number of genes that have these very large introns but this should be a small number. Furthermore, most popular sequence aligners tend to set ...


4

Yes, check out HOTAIR (in human), as well as cyrano and megamind in zebrafish -- they are all spliced.


4

Do you call ribosomal RNA non-coding? rRNA is spliced both in prokaryotes and eukaryotes.


4

The answer is not simple - @shigeta mentioned a few mechanisms leading to single gene-to-multi protein relationships - and the answer is certainly not short (there are thousands of these genes). But anyway "alternative splicing" seems to be the primary mechanism according to this article, so rather than listing all alternatively splicing genes, here are the ...


4

There are a large number of ways a protein variant can be produced by post translational modification. The question may seem obvious, but its really quite broad. I can start this out. I doubt I know all the ways a single transcript can produce variant proteins. A detailed description might be more like a review article than an answer here. First, ...


4

Trimming = removing RNA sequences from one end. Splicing = removing introns and joining exons back together.


3

Just for balance, here is an example of a single protein being constructed from two primary gene products (two separate genes involved) via protein splicing.


2

There are references in the literature to the phenomenon of "exon scrambling" which seems to be what you are asking about, but the prevailing view is that the evidence for this process, which comes from comparing EST sequences with genome sequences, can be explained by cloning artefacts occurring during EST characterisation. Certainly I agree that there is ...


2

You can see this review. There are several different types of alternative splicing (AS) events, which can be classified into four main subgroups. The first type is exon skipping, in which a type of exon known as a cassette exon is spliced out of the transcript together with its flanking introns (see the figure, part a). Exon skipping accounts ...


2

RNA splicing refers to a certain kind of RNA processing mechanism which leads to the excision and exclusion of some regions of the primary transcript. You should note that this is not the only method by which such a thing can happen; Endo-ribonucleases can clip the ends of the transcript and this happens in the case of tRNA-processing. But as "splicing" ...


1

RNA splicing begins with assembly of helper proteins at the intron/exon borders. These splicing factors act as beacons to guide small nuclear ribo proteins to form a splicing machine, called the spliceosome. These animation is showing this happening in real time. see> ...


1

Co-transcriptional splicing (CTS) is very widespread. Different studies (which are done on different cell types) report different frequencies of CTS. Most of them report a frequency of ~0.8 in different cells except for mouse liver which was reported to have a frequency of 0.45 This is the article that summarizes these different studies. Can transcription ...


1

As Alan Boyd said, this process is called trans splicing where exons of different RNAs are joined together. Physical proximity is conducive for trans-splicing. This study shows that trans-splicing frequency is higher if the genes are proximal. Proximity not only means closer in the genome but also the 3D proximity governed by chromosomal interactions. Now, ...



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