[mage lang=”en|es|fr|en” source=”flickr”]telomerase rna primer[/mage] what exactly happens after telomerase is used?
I know that it is an enzyme that has a short molecule of RNA with a sequence that serves as a template for extending the 3′ end of the telomere. But I see that after the primer is removed from 5′ it is still shorter than the other strand 3′. this is what it says in teh book”After the primer is removed, the result is a longer telomere with a 3′ -end “overhang (LM).” So what this mean?
Telomerase is an enzyme that adds specific DNA sequence repeats (“TTAGGG” in all vertebrates) to the 3′ (“three prime”) end of DNA strands in the telomere regions, which are found at the ends of eukaryotic chromosomes. The telomeres contain condensed DNA material, giving stability to the chromosomes. The enzyme is a reverse transcriptase that carries its own RNA molecule, which is used as a template when it elongates telomeres, which are shortened after each replication cycle. Telomerase was discovered by Carol W. Greider in 1984.
[mage lang=”en|es|fr|en” source=”flickr”]telomerase primer[/mage] what is the use of telomere and telomerase?
I know they both help solve problems that fills in gaps at the of 5′. But my question really is why is there gaps there? is it because the primer just leaves and the DNA polymerase doesnt give a damn about replacing RNA with DNA or what?
Well, sort of.
DNA polymerase has specific functions, it can replace RNA primers with DNA, but mechanistically it has to do it in a 5` to 3` direction.
So think about your 2 strands. 1 is a continuous polymerization, and has the 1 RNA primer at it’s 5` end. DNA polymerase has nothing upstream of that to bind to, thus resulting in missing DNA.
The other strand is the one that’s made up of Okazaki fragments (so that there are many short 5-3 replications due to the over all movement of DNA polymerase in the opposit direction of the DNA strand). All of those primers can get replaced except the very 5` one again, leaving a little missing DNA on both strands.
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