Cell fate specification in the amphipod crustacean Parhyale

Matthias Gerberding
I have recently moved to Hohenheim University.

E-mail: m.gerberding (at) uni-hohenheim.de
Embryonic development in model organisms and in Parhyale hawaiensis

Our molecular understanding of animal development is based on studies of model organisms such as the fruit fly Drosophila melanogaster and the round worm C. elegans. These studies open up questions that lead to the study of non-model organisms. One question is whether the mechanisms recognized in models apply to non-models, another is whether non-models use unknown mechanisms, the third is how developmental mechanisms were acquired during evolution, and the fourth is what the molecular basis for animal phenotypic diversity is.

We study the early development of a non-model arthropod, the amphipod crustacean Parhyale hawaiensis. It shows unique features that are not present in the model arthropod Drosophila and it is amenable to various experiments. Early cleavage is total, unequal and invariant. It generates cells of different sizes and properties. We followed the development of these cells by injecting markers at the 8-cell stage. The experiments showed that the progenitors generate distinct clones with different cell fates. The progenitors exclusively contribute to only one of the germ layers. Time-lapse recordings have revealed suites of cell behavior among the clones. For example, the ectoderm clones show a left-right symmetry.

Goals of investigation

We aim fo find genes that set up the germ layers in Parhyale. Because in Parhyale germ layer specification and cell lineage are linked, we search for genes differentially upregulated within the cell lineages. If we can study the function of genes by knockdown or overexpression, we address questions as: Which signals establish the differences between the eight blastomeres? How do differences between blastomeres result in the germ layer specification? And finally, if early cleavage while specifying cell fate also allocates cells along the the anterior-posterior and dorsal-ventral axes, how are these two processes linked?

Cell lineage of the 8-cell stage of Parhyale

Each germ layer originates from a distinct subset of cells of the 8-cell stage. The ectoderm derives from macromeres "Er", "Ep", "El", the somatic mesoderm from micromeres "mr", "ml", the germ line from micromere "g", the visceral mesoderm from macromere "Mv", and the endoderm from micromere "en".

Kizil G, Havemann J, Gerberding M (in press) Germ cells in the crustacean Parhyale hawaiensis depend on Vasa protein for their maintenance but not for their formation. Developmental Biology

Havemann J, Müller U, Berger J, Schwarz H, Gerberding M and Moussian B. (2008) Cuticle differentiation in the embryo of the amphipod crustacean Parhyale hawaiensis. Cell & Tissue Research. 332, 359-370. [pdf]

Browne, W. E., Price, A. L., Gerberding, M., Patel, N. H.. (2005). Stages of Embryonic Development in the amphipod crustacean, Parhyale hawaiensis. Genesis 42, 124-149. [pdf]

Gerberding, M., and Patel, N.H. (2004) Gastrulation in crustaceans. In: Gastrulation. (ed. C. Stern). Cold Spring Harbor: CSHL Press, 78-89 [pdf]

Gerberding, M., Browne, W. E., and Patel, N.H. (2002) Cell lineage analysis of the amphipod crustacean, Parhyale hawaiensis, reveals an early restriction of cell fates. Development 129: 5789-5801 [pdf]

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Links to Parhyale labs

Nipam Patel lab, UC Berkeley

Michalis Averof lab, IMBB, Crete

Cassandra Extavour lab, Harvard University

Bill Browne, U of Hawaii

Ernst Wimmer lab, Göttingen University