| Name | Institution | e-mail (optional) |
| King Henry VIII | Hampton Court Palace Kingston |
Henry8@rex.gov.uk |
|
Template Method What's this about? You can use this template method to write your own method into HTML (HyperText Markup Language)
(Whoa! This is way too
complex OK, how do I do it? (1) First of all you want to "view-source" for this page. On a PC click the right mouse
button around here on the page
and a list of options comes up.
Select "view-source" by clicking the left mouse button.
A
new
window
will open up
showing
the
raw data
that
your
browser program (Internet Explorer or Netscape)
has retrieved and converted into the nice blue page. It is a simple text
file and you can edit it and save it.
When you save it be sure to select "all files" in the save
file dialogue-box and name the file
something like myfile.html (2) Try changing something now. Find this text, change it to something silly then save it and open the saved file with your browser program. Either choose "open file" whilst in the browser program or find your saved file first and double-click on it to automatically open the browser. (3) Straight away you notice a problem. It doesn't look right. Several things are wrong. First,
near
the top of the document, just beneath the title, there is a tag commencing "<link rel="stylesheet......
This asks the browser program to locate a short file defining certain styles (the stylesheet). This file
is supposed to be one directory up ( ../ ) and its called mbstyle.css Second, shortly after the stylesheet request there are two <iframe> tags. iframe stands for
inline frame.
These tags each ask for a file to
go in a defined space at the top of the page. The files are not where the browser expects to find them
(again, one directory up ( ../ ),called navbar.html and discpat.html) (4) So, to make your page look nice you need a stylesheet (a file called something.css) (in this case called mbstyle.css) and you need to do something about the iframe spaces. (5) You can learn about stylesheets elsewhere (Webmonkey) but just for now use the one below. Copy and paste the lines below into a new page in notepad or simpletext (the free, basic text editor that comes with your computer). Then save it as mbstyle.css (be sure to save it as plain text and as "all-files" otherwise it will end up really being called mbstyle.css.txt and that won't work.)
<!-- this is my stylesheet, poor as it is -->
|
| Duration | Temperature | Cycles |
| 60 seconds | 94C | 1 |
| 30 seconds | 94C | 12 |
| 30 seconds | 55C | |
| 12 minutes | 68C |
The extension temperature is 68C to minimize 'breathing' of the 5' end of primer. Then, when the polymerase has read all the way around the plasmid it is less likely to displace the primer and incorporate the 'old' sequence from the plasmid. The extension time is 2 minutes per kb of plasmid.
Cool the PCR reaction to room temperature and add 1ml of restiction enzyme DpnI.
Incubate at 37C for 1 hour.
DpnI is a 4-cutter which only cuts dam methylated DNA. The parental plasmid DNA will be cut to pieces whilst the nascent PCR DNA is left intact. All routine E.coli strains have an intact dam methylase system. Check in the back of the NEB catalogue if unsure.
Transform 5ml and 45ml of the reaction into competent E.coli.
There is no need to carry out a ligation before the transformation. The PCR product is a 'nicked' circle with the nicks in opposite strands displaced by 42bp. This is identical to a classical de-phosphorylated vector plus insert transformation (with a 42bp insert).
Miniprep some colonies, check that they are the expected size and screen 2 of them by sequencing.
I've done this twice and each time both colonies were the correct thing. I then subclone the gene out of the plasmid back into the vector in the classical way to avoid sequencing the whole vector for any PCR errors.
| No responsibility is assumed by methodbook for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions or ideas contained in the material herein. It is the users responsibility to ensure that all procedures are carried out according to appropriate Health and Safety requirements. Matthew Hopkin Lewis = matt@methodbook.net |
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