cloning into Casper

[S.Bartoszewski]

In article <friedmrd-1711950953010001 at n1-2-210.macip.drexel.e> friedmrd at post.drexel.edu (Richard Friedman) writes:
>In article <47uf3e$oqk at manuel.anu.edu.au>, S. Bartoszewski wrote:
>
>> >myersm at rockvax.rockefeller.edu
>> 
>> I used a vector similar to Casper, and I had very low efficiency in cloning 
>> fragments larger than ~10 kb.  In some cases constructs rearranged.  I found
>> out that, the P-element flanks used in the vector were taken from its 
>> insertion into white gene.  Since the vector contains also white gene, these
>> sequences (~200 and ~400bp) are repeated and may enable intramollecular
>> recombination, which I could observe.  I used E.coli DH5-alfa.  You may 
>> check Casper's sequence, whether it contains direct repeats.  Slawek.
>
>Out of curiosity, which vector are you using. I am trying to clone large
>fragments into pBecky Blocker 5 ( a Casper derivative) and have used JM109
>to transform.
>
I am using pW8 [Klemenz, Weber & Gehring (1987) NAR 15; 3947-3959].  It is not
a derivative of pCaSpeR, but was constructed independently in a very similar
way.  I don't know about using JM109, I would check whether it is recA.  
Slawek

E-mail: slawek at rsbs-central.anu.edu.au