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summary cosuppression/antisense

Thomas Altmann altmann at mpimg-berlin-dahlem.mpg.de
Fri Feb 9 08:45:10 EST 1996

Dear colleagues,
many thanks to all who replied to my question about comparison of
cosuppression and antisense.
Here is the summary.
Thanks again,

Thomas Altmann

Karl-Liebknecht-Str.25, Haus 20
14476 Golm

phone: ++49-331-9772780
fax:   ++49-331-9772301
e-mail: altmann at mpimg-berlin-dahlem.mpg.de



You might be interested in looking at the antisense inhibition of ethylene
production by antisense ACC synthase in tomato.  This work was done by
A.Theologis and colleagues at the Plant Gene Expression Center in Palo Alto,
CA.  Ethylene synthesis is completely abolished in these plants.  I really
don't have any information on cosuppression, but the ACC synthase work was
published in Science magazine, and is the best example of the usefulness of
antisense technology that I know of.

Joe White       (whitejo at pilot.msu.edu)
301 Biochemistry
Michigan State University
East Lansing, MI  48824


Dear Thomas:

   I would like to say it is hard to compare the efficiency
between cosupression and anti-sense.  Some people thjnk that
the results obtained from anti-sense inhibition are actually
operated by cosupression.  There is an article describing the
proposed model of copression/anti-sense inhibition in " Current
Opinion in ???" in 1995.  That article is not with me right now
and I could not tell you where it comes from.  If you want to
know that article, please e-mail me and I can check it for you.

 The reference is

Transgenes and gene supression: telling us something new?
William G Dougherty and T Dawn Parks
Current Opinion in Cell Biology (Nucleus and gene expression) June 1995: 399-405



Hi,  I isolated some very stable cosuppressed lines in Arabidopsis a few
years back.  The cosuppression was stable through four backcross
generations.  I had a cab promoter fused to a reporter tms2 gene, and
cosuppression occured at the level of transcription.  Transcript levels
were reduced about  10 fold.  Cosuppression occured at all times during
development that were tested- seedlings, mature leaves, even bolting
plants.  The frequency of isolating these cosuppressed lines was low
about 8 X 10 -5. so perhaps not very paractical! Cosuppression involving
the open reading frame seems to occur at a much higher frequency.  Good
luck, Judy Brusslan  For more info see The Plant Cell 5, 667-677 and
Plant Molecular Biology 27, 809-813. .


Dear Thomas,

A colleague of mine saw your request about co-suppression and
antisense inhibition on the net. Last year I finished my PhD research
about co-suppression / antisense inhibition  of the
Granule Bound Starch Synthase and Branching Enzyme genes,
both enzymes are involved in the starch biosynthesis. The work
was done at the department of Plant Breeding of the Agricultural
University in Wageningen, The Netherlands, under supervision of Dr.
Richard Visser and Prof Evert Jacobsen.

Comparing my results of sense inhibiting the GBSS-gene with the
results on antisense inhibition of the GBSS-gene investigated by
my colleague Anja Kuipers (still working at the department of Plant
Breeding) I found:

" The frequency of wild-type plants showing sense inhibition using
the full length GBSS-DNA and GBSS-promoter was lower (10 %)
 compared to antisense inhibition (52 %; Kuipers et al., 1995).
The frequency of plants with a complete inhibition was similar (3 %)
 as was its positive correlation with the number of T-DNA inserts".

A paper containing this result together with other findings is
submitted to Plant Molecular Biology with the following title:

GBSS T-DNA inserts giving partial complementation of the amylose-free
mutant can also cause co-suppression of the endogenous GBSS-gene in a
wild-type background.
E Flipse, I Straatman-Engelen, GJ Kuipers, E Jacobsen RGF Visser.

The other reference is:
GJ Kuipers, WJJ Soppe, E Jacobsen, RGF Visser
Factors affecting the inhibition by antisense RNA of granule-bound
starch synthase gene expression in potato. Mol Gen Genet 246:745-755,

In another part of my thesis I describe the inhibition of the BE-gene
expression by introducing  sense and anti-sense cDNA for Branching
Enzyme (BE) in the amylose-free potato mutant. Although the percentage of
transgenic plants showing inhibition of the BE-gene was similar for
both sense and antisense a higher level of inhibition was found when
the antisense construct as used.
This work is accepted for publication in Planta with the title:
Introduction of sense and antisense cDNA for Branching Enzyme in the
amylose-free potato mutant leads to physico-chemical changes in the
E Flipse L Suurs, CJAM Keetels, J Kossmann, E Jacobsen RGF Visser.

I did not focus my work on the stability of the inhibition but Anja
Kuipers has written an article titled:

Field evaluation of transgenic potato plants expressing an antisense
granule-bound starch synthase gene: increase of the antisense effect
in starch granules during tuber development.
Plant Molecular Biology 26: 1759-1773.

I hope I could have helped you, please contact me whenever you have
more questions. I am interested to know what other replies you have got.

Greetings Elise Flipse

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