Strange positive in two-hybrid screen

Ralf Weigel weigeler at
Tue Oct 7 15:14:52 EST 1997

Dear Frederik,

I found a similar one, growing on 45mM 3-AT and expressing lacZ weakly,
even after retransformation. The sequencing data revealed the addition
of one (!) aa to the Gal4AD. The insert is highly homologous to an EST,
but obviously inverted due to bidirectional cloning. The most mysterious
thing is that this false positive is bait-dependent. It does not show
reporter gene expression on its own or with any other bait I tried. 


Frederik Boernke wrote:
> Hi all,
> during our last two-hybrid screen we obtained one clone showing growth
> on 25 mM 3-AT and expression of the lacZ reporter gene. We retransformed
> the activation domain plasmid into E.coli and than sequenced the entire
> inserted cDNA fragment. To our surprise the sequence revealed no ORF
> longer than a few amino acids. 

R. Weigel
General Virology
Institute of Genetics
University of Hohenheim
Emil Wolff Str.14
70599 Stuttgart
Tel.: +049/711/4592395
Fax: ~4592937

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