There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
Germ cells are a population of cells that do not differentiate to form somatic tissue
but form the egg and sperm that ensure the reproduction of the organism. To understand
how germ cells form, holds a key for identifying what sets them apart from all other
cells of the organism. There are large differences between embryos regarding where
and when germ cells form but the expression of Vasa protein is a common trait of germ
cells. We studied the role of vasa during germ cell formation in the crustacean Parhyale
hawaiensis. In a striking difference to the posterior specification of the group of
germ cells in the arthropod model Drosophila, all germ cells in Parhyale originate
from a single germ line progenitor cell of the 8-cell stage. We found vasa RNA ubiquitously
distributed from 1-cell to 16-cell stage in Parhyale and localized to the germ cells
from 32-cell stage onwards. Localization of vasa RNA to the germ cells is controlled
by its 3'UTR and this could be mimicked by fluorescently labeled 3'UTR RNA. Vasa protein
was first detectable at the 100-cell stage. MO-mediated inhibition of vasa translation
caused germ cells to die after gastrulation. This means that in Parhyale Vasa protein
is not required for the initial generation of the clone of germ cells but is required
for their subsequent proliferation and maintenance. It also means that the role of
vasa changed substantially during an evolutionary switch in the crustaceans by Parhyale
from the specification of a group of germ cells to that of a single germ line progenitor.
This is the first functional study of vasa in an arthropod beyond Drosophila.