An important step in the development of a flatworm model organism

On December 20, the paper “Transcriptional signatures of somatic neoblasts and germline cells in Macrostomum lignano” was published in eLife (http://dx.doi.org/10.7554/eLife.20607). The author’s summary of the paper is presented below.

An important step in the development of a flatworm model organism
Flatworms are largely known for their astonishing regeneration abilities. An amputated head, for example, can regrow its entire body, including the reproductive organs, within a period as short as three weeks! This is attributed to the presence of somatic stem cells, and thus studying how regeneration is regulated in flatworms can provide fundamental insights into stem cell biology. One of the flatworm species, Macrostomum lignano, is increasingly used as a model organism for research on stem cell biology, regeneration, and ageing, not the least thanks to the efforts of the Berezikov group. Establishing the transcriptome of the animal, which provides information on genes that are present in the genome, is a crucial part of developing a modern model organism, and identifying genes that are specifically expressed in stem cells is particularly important for a model organisms geared for stem cell research. These two milestones are described in the article published in eLife (lead authors Magda Grudniewska and Stijn Mouton). One of the main challenges for identifying stem cell genes was to distinguish between stem cells and germline cells, the two types of cells that divide in this animal. To achieve this, the authors used a combination of irradiation, which kills dividing cells, and fluorescence-activated cell sorting from different stages of animal development and regeneration, which selects for cells in different stages of cell cycle, and RNA sequencing analysis. As a result, the first comprehensive characterization of gene expression in the proliferating cells of M. lignano was established and a number of genes specific for stem cells and germline cells were identified. For several of the novel identified genes their crucial role in stem cell function was demonstrated.
This work is an important step towards wider adoption of M. lignano as a model organism, and the generated datasets will be a valuable resource for future molecular studies in M. lignano, other flatworms species, and, importantly, stem cell biology in general.