First published online May 30, 2007
Development 134, 1202e (2007)
© The Company of Biologists Limited
Streamlining oocyte growth
Cytoplasmic streaming - in which RNA and protein is transported from
polyploid nurse cells to the growing oocyte - in Drosophila is well
documented; however, little is known about how cytoplasmic materials
accumulate in growing C. elegans oocytes, which lack nurse cells.
James Priess's lab now reveals that mitochondria and germline-specific
proteins - in addition to injected foreign material, such as oil droplets or
polystyrene beads - travel from the gonad region, where pachytene nuclei are
situated, to the oocyte, supporting the view that pachytene-stage nuclei
function as transient nurse cells before differentiating into oocytes (see
p. 2227).
Interestingly, and in contrast to Drosophila where cytoplasmic
materials are pushed into the oocyte from nurse cells, in the worm cytoplasmic
material is pulled into the enlarging oocyte by acto- and myosin-dependent
forces generated adjacent to, or even within, the enlarging oocyte.
RNAi-knockdown studies reveal that microtubules are not essential in this
streaming event. Future studies are likely to focus on the molecular
mechanisms that regulate this key process.
Related articles in Development:
- Actin-dependent cytoplasmic streaming in C. elegans oogenesis
- Uta Wolke, Erin A. Jezuit, and James R. Priess
Development 2007 134: 2227-2236.
[Abstract]
[Full Text]