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dictyNews Volume 23 Number 15
Dicty News
Electronic Edition
Volume 23, number 15
November 5, 2004
Please submit abstracts of your papers as soon as they have been
accepted for publication by sending them to dicty@northwestern.edu
or by using the form at
http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit.
Back issues of Dicty-News, the Dicty Reference database and other
useful information is available at dictyBase - http://dictybase.org.
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Abstracts
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The Calcineurin Inhibitor Gossypol Impairs Growth, Cell Signalling and
Development in Dictyostelium discoideum
Barbara Weissenmayer, Katrina Bckeler, Angela Lahrz and Rupert Mutzel
Institut fr Biologie - Mikrobiologie, Fachbereich Biologie, Chemie,
Pharmazie, Freie Universitt Berlin, Knigin-Luise-Strasse 12-16,
14195 Berlin, Germany
FEMS Microbiology Letters, in press
The Dictyostelium genome harbors single copy genes for both the catalytic
and regulatory subunits of the Ca2+/calmodulin-dependent protein phosphatase
calcineurin. Since molecular genetic approaches to reduce the expression of
these genes have failed so far, we attempted to pharmacologically target
calcineurin activity in vivo by using the recently described calcineurin
inhibitor, gossypol. Up-regulation of expression of the gene for the
Ca2+-ATPase PAT1 in conditions of Ca2+ stress was reduced by gossypol.
Dictyostelium wild-type cells treated with 12.5 to 100 µM gossypol showed
reduced growth rates and impaired development. In addition, cell signalling
was affected. A cell line that overproduces the catalytic subunit of
calcineurin was more resistant to gossypol.
Submitted by: Barbara Weissenmayer [bweiss@zedat.fu-berlin.de]
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Nuclear Pore Complex Structure and Dynamics revealed by Cryoelectron
Tomography
Martin Beck, Friedrich Frster, Mary Ecke, Jrgen M. Plitzko, Frauke
Melchior, Gnther Gerisch, Wolfgang Baumeister and Ohad Medalia
Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
Science, in press.
Nuclear pore complexes (NPCs) are gateways for nucleocytoplasmic exchange.
To analyse their structure in a close-to-life state, we studied
transport-active, intact nuclei from Dictyostelium discoideum by means of
cryoelectron tomography. Subvolumes of the tomograms containing individual
NPCs were extracted in silico and subjected to three-dimensional
classification and averaging, whereby distinct structural states were
observed. The central plug/transporter (CP/T) was variable in volume and
could occupy different positions along the nucleocytoplasmic axis,
supporting the notion that it essentially represents cargo in transit.
Changes in the position of the CP/T were accompanied by structural
rearrangements in the NPC scaffold.
Submitted by: Wolfgang Baumeister [baumeist@biochem.mpg.de]
and Ohad Medalia [omedalia@biochem.mpg.de]
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[End Dicty News, volume 23, number 15] 
