Monte Westerfield Monte at
Tue Aug 9 14:50:25 EST 1994

In article <31tqqg$bj3 at>, saparici at (Dr.
S.A.J.R. Aparicio) wrote:

> OK, just to see if anyone is watching ....
> I have heard a number of conflicting statements about transgenesis in Danio
> at meetings this summer. I understand that while it is possible to 
> generate transgenic zebra fish, they are mosaic. If the mosaicism is
> bred out by backcrosses, the level of expression of the transgenes falls
> off precipitously by the F2 generation. The question is why this should
> be so? One explanation was that most promoters used for lacZ expression
> so far, have been non-teleost. Another was that the integrated copies
> of the transgene are unstable in the zebrafish genome and rapidly
> become fragmented. 
> Does anyone have any data/experience to shed light on this?
> Dr Samuel Aparicio
> Molecular Genetics Unit
> Level 5
> Addenbrookes Hospital
> Cambridge CB2 2QQ
> UK
> saparici at

This is not necessarily true.  Check Stuart et al., Development 109:
577-584 (1990), who demonstrated that lines can be generated that express
transgenes under the control of non-teleost promoters.  These lines and
several others, including ones that express lacZ, have been carried through
many generations with no loss of expression.

It may be that the site and nature of the integration event affect the
level of expression and stability of the transgene.

Monte Westerfield
Institute of Neuroscience
University of Oregon

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