dictyNews
Electronic Edition
Volume 45, number 3
January 25, 2019
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Abstracts
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A Well Supported Multi Gene Phylogeny Of 52 Dictyostelia
Christina Schilde1, Hajara M. Lawal1, Koryu Kin1, Ikumi S. Hayakawa2,3,
Kei Inouye3 and Pauline Schaap1*
1School of Life Sciences, University of Dundee, Dundee DD15EH, UK
2Department of Physics,
3Department of Botany, Graduate School of Science, Kyoto University,
Kyoto 606-8502, Japan
Molecular Phylogenetics and Evolution, in press
The Dictyostelid social amoebas are a popular model system for cell- and
developmental biology and for evolution of sociality. Small subunit (SSU)
ribosomal DNA-based phylogenies subdivide the known 150 species into
four major and some minor groups, but lack resolution within groups,
particularly group 4, and, as shown by genome-based phylogenies of 11
species, showed errors in the position of the root and nodes separating
major clades. We are interested in the evolution of cell-type specialization,
which particularly expanded in group 4. To construct a more robust
phylogeny, we first included 7 recently sequenced genomes in the genome-
based phylogeny of 47 functionally divergent proteins and next selected 6
proteins (Agl, AmdA, PurD, PurL, RpaA, SmdA) that independently or in sets
of two fully reproduced the core-phylogeny. We amplified their coding regions
from 34 Dictyostelium species and combined their concatenated sequences
with those identified in the 18 genomes to generate a fully resolved phylogeny.
The new AAPPRS based phylogeny (after the acronym of the 6 proteins)
subdivides group 4 into 2 branches. These branches further resolve into 5
clades, rather than the progressively nested group 4 topology of the SSU
rDNA tree, and also re-orders taxa in the other major groups. Ancestral state
reconstruction of 25 phenotypic traits returned higher “goodness of fit” metrics
for evolution of 19 of those traits over the AAPPRS tree, than over the SSU
rDNA tree. The novel tree provides a solid framework for studying the
evolution of cell-type specialization, signalling and other cellular processes in
particularly group 4, which contains the model Dictyostelid D. discoideum.
submitted by: Pauline Schaap [[log in to unmask]]
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Collective cell migration of Dictyostelium without cAMP oscillations at
multicellular stages
Hidenori Hashimura, Yusuke V. Morimoto, Masato Yasui, Masahiro Ueda
Communications Biology, 2: 34
In Dictyostelium discoideum, a model organism for the study of collective cell
migration, extracellular cyclic adenosine 3’,5’-monophosphate (cAMP) acts as
a diffusible chemical guidance cue for cell aggregation, which has been thought
to be important in multicellular morphogenesis. Here we revealed that the
dynamics of cAMP-mediated signaling showed a transition from propagating
waves to steady state during cell development. Live-cell imaging of cytosolic
cAMP levels revealed that their oscillation and propagation in cell populations
were obvious for cell aggregation and mound formation stages, but they gradually
disappeared when multicellular slugs started to migrate. A similar transition of
signaling dynamics occurred with phosphatidylinositol 3,4,5-trisphosphate
signaling, which is upstream of the cAMP signal pathway. This transition was
programmed with concomitant developmental progression. We propose a new
model in which cAMP oscillation and propagation between cells, which are
important at the unicellular stage, are unessential for collective cell migration at
the multicellular stage.
submitted by: Yusuke Morimoto [[log in to unmask]]
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RB431, RB432, RB433, RB434, and RB435 antibodies recognize a
Dictyostelium RapA peptide by ELISA
Philippe Hammel, Wanessa C Lima
Antibody Reports, 2019, vol. 2, e12
https://doi.org/10.24450/journals/abrep.2019.e12
The recombinant antibodies RB431, RB432, RB433, RB434, and RB435 detect
by ELISA a synthetic peptide from the Dictyostelium RapA protein.
submitted by: Wanessa du Fresne von Hohenesche [[log in to unmask]]
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RB438, RB440, RB441 and RB442 antibodies recognize a Dictyostelium
Nup133 peptide by ELISA
Philippe Hammel, Wanessa C Lima
Antibody Reports, 2019, vol. 2, e14
https://doi.org/10.24450/journals/abrep.2019.e14
The recombinant antibodies RB438, RB440, RB441 and RB442 detect by ELISA
a synthetic peptide from the Dictyostelium Nup133 protein.
submitted by: Wanessa du Fresne von Hohenesche [[log in to unmask]]
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[End dictyNews, volume 45, number 3]
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