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. ============= Abstracts ============= 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] ----------------------------------------------------------------------------- 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] ============================================================================== [End Dicty News, volume 24, number 12]