Unstable Construct

[CHENJF at HELIX.MGH.HARVARD.EDU]

Dear Netter:
I run into serious problem with an appearent unstable construct.  I made a 
construct with pGM7 as backbone, a Neo gene as marker (2 kb) and two inserts
(about 5 and 6 kb respectively).  I was able to detect both inserts by
hybridization in plate screening.  However, I lost my constructs when I grow
them up in the medium.  Occasionaly, I retained my consturcts but so for I
have screening more than 600 clones and obtained four constructs with inserts
ALL in wrong orientation.  I do not know why this happened.  I hope someone
out there can suggest me a solution.  Any input is greatly appreciated.
Thanks in advance.

Jiang Fan Chen
Mol. Neurobiol. Lab.
Mass. Gne. Hospital
617-726-5714 (Tel)
617-726-5677 (Fax)