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dictyNews Volume 24 Number 12
Dicty News
Electronic Edition
Volume 24, number 12
May 06, 2005
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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Novel patterns of the gene expression regulation in the prestalk region
along the antero-posterior axis during multicellular development of
Dictyostelium
Yoko Yamada, Haruyo Sakamoto, Satoshi Ogihara and Mineko Maeda
Biological Science, Graduate School of Science, Osaka University,
Machikaneyama 1-1, Toyonaka, Osaka 560-0043, Japan
Gene Expression Patterns, in press
Simultaneous hybridization with differentially labeled fluorescent probes
for in situ hybridization analysis revealed several novel expression
patterns of prestalk genes during multicellular development of
Dictyostelium. Seven prestalk genes and one prespore gene (pspA) were
analyzed in this study. The patterns identified here indicate that prestalk
cells are more heterogeneous than previously thought. Heterogeneity was
observed in peripheral prestalk tissues such as the pstAO domain of a slug
and the prestalk region surrounding a stalk tube of a culminant.
Heterogeneity was also observed in the core pstAB cells of the slug and
immature stalk cells within the stalk tube. The upper and lower cups of a
late culminant were also composed of several subdomains.
Submitted by: Mineko Maeda [mmaeda@bio.sci.osaka-u.ac.jp]
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Glycoprotein gp130 of Dictyostelium discoideum influences macropinocytosis
and adhesion
Catherine P. Chia*, Sujatha Gomathinayagam, Robert J. Schmaltz and
Laura K. Smoyer
Molecular Biology of the Cell, in press
Glycoprotein gp130, found on the plasma membrane of Dictyostelium discoideum
amoebae, was postulated previously to play a role in phagocytosis. The gene
for gp130 was cloned and when translated, yielded a 768 amino acid
preproprotein of 85.3 kDa. It had nearly 40% similarity to the 138 kDa family
of glycoproteins implicated in sexual cell fusion during macrocyst formation
in D. discoideum. The difference between the calculated size and observed Mr
of 130 kDa on protein gels likely was due to N-glycosylation that was
confirmed by lectin blots. Consistent with its surface-exposure, an antibody
raised against recombinant protein stained the plasma membrane of
D. discoideum amoebae. Gp130 and its transcripts were high during axenic
growth of cells, but relatively low during growth on bacteria. The gene for
gp130 was disrupted and cell lines lacking the glycoprotein were efficient
phagocytes, indicating that gp130 was dispensable for phagocytosis.
Gp130-null cells were similar in size to parent DH1 cells, had enhanced
macropinocytosis and grew faster to higher densities. They also exhibited
weaker cell-substrate adhesion but displayed greater cell-cell cohesion.
Collectively, the data indicated that gp130 influenced macropinocytosis
and played a role in adhesion during vegetative growth.
Submitted by: Cathy Chia [cchia@unlserve.unl.edu]
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[End Dicty News, volume 24, number 12] 
