bg_worm
macgenome.org home
Macrostomum lignano
genome initiative
ERIBA

Emerging model for stem cell research

Macrostomum lignano is a free-living flatworm with high regeneration capacity facilitated by neoblasts, the stem cell system of the worm. It was first discovered in 1995 (described as a species in 2005) and since then has been the subject of research in several laboratories.

Due to its small size, short generation time, amenability to genetic manipulation and easy maintenance in laboratory conditions, M. lignano is a highly promising invertebrate experimental model whith a potential to become the next "C. elegans for stem cell research".

Sequencing and annotation of M. lignano genome has been initated at Hubrecht Institute (E. Berezikov) and currently is carried out by an informal consortium of several research groups.

 
M.lignano
Macrostomum key features
Sizeadults 1-1.5 mm; hatchlings 300µm
Cell numbers~25.000 total; ~1600 neoblasts; ~400 S-phase, ~25 mitotic
Culture in laboratoryeasy; feed on diatoms; kept in Petri dishes with algae and light
Transparencyhighly transparent
Embryogenesis5 days; Spiral quartet
Generation time18 days
Reproductionexclusively sexual; obligatory cross-fertilizing hermaphrodite; lay single cell eggs (100µm)
Accessibility to eggssingle eggs, whole year through
Nervous systemsimple; brain with neuropile; 2 main lateral nerve cords; a pair of dorsal and ventral cords; 16 serotoninergic cells; limited number of peptidergic nerve cells
Muscle system3 layers, outer circular, inner longitudinal and diagonal muscles
Testescontinuous sperm production; surrounded by tunica cells; outer region with spermatogonia and spermatocytes; below spermatids; inside mature sperm.
Ovariesoogonia and oocytes;
Morphological knowledgewell established
Plasticityhigh; can endure extreme starvation (degrowth); testes size depends on group size
Regeneration potentialhead regenerates posterior end with gonads; posterior end makes no new head
Phylogenetic positionbasal platyhelminth; member of Lophotrochozoa
Stem Cell Systempluripotent
BrdU/H3 Stainingeasy by soaking
RNA interferenceeasy by soaking
Amenable to forward and reverse geneticsyes
Genome size and availability600 MB, 5x coverage; early draft online