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<div class="step">1. 2.</div> | <div class="step">1. 2.</div> | ||
<div class="title">Unequal replication</div> | <div class="title">Unequal replication</div> | ||
− | <p> Replication machinery is not able to discriminate between similar Ori sites, therefore smaller plasmids are replicated faster, thus rapidly outgrowing larger plasmids leading to uneven plasmid ratios in | + | <p> Replication machinery is not able to discriminate between similar Ori sites, therefore smaller plasmids are replicated faster, thus rapidly outgrowing larger plasmids leading to uneven plasmid ratios in a cell.</p> |
<h6>Problem #1</h6> | <h6>Problem #1</h6> | ||
</div> | </div> |
Revision as of 21:34, 31 October 2017
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Present challenges of
experimenting with plasmid systems
Origin of replication (Ori) is a sequence where the plasmid replication is initiated. Plasmids with similar Ori sites use the same replication machinery.
Problem #1
Replication machinery is not able to discriminate between similar Ori sites, therefore smaller plasmids are replicated faster, thus rapidly outgrowing larger plasmids leading to uneven plasmid ratios in a cell.
Problem #1
This is even more likely to occur when the plasmid copy number is low. When the cell divides, lower copy plasmids tend to be lost in next generations.
Problem #1
One needs to use different types of Ori to avoid this trouble, however it often causes dilemma due to limited selection options or the lack of good combination of Ori and plasmid‘s copy number.
Problem #2
Imagine you require a system consisting of two - low and high copy plasmids. Try picking them from the list above and see what happens.
Problem #2
Currently no handy method of changing the copy number of particular plasmid exists.
Problem #2
There is also no mechanism to adjust the copy number when so is required in any specific situation: for example, incoming cellular signals or special patterns.
Problem #2
Did this look smart, easy or convenient?
We think it is time for a change.
A
B
C
D
Plasmid
Copy number