First published online October 30, 2006
Development 133, 2204e (2006)
© The Company of Biologists Limited
A new twist to LR asymmetry
The establishment of the embryonic axes is a crucial developmental event.
Anteroposterior and dorsoventral axis determination is reasonably well
understood, but in some organisms the earliest steps of left-right (LR) axis
formation remain unclear. Now Danilchik and co-workers describe an intrinsic
chirality in the cortex of Xenopus eggs that might predetermine this
animal's LR asymmetry (see p.
4517). They report that one-cell Xenopus embryos and
parthenogenetically activated eggs undergo a twisting motion in which the
animal pole rotates counterclockwise past the vegetal cortex after treatment
with 2,3-butanedione monoxime (BDM), which disrupts actinmyosin interactions.
BDM treatment, they report, induces a shear zone parallel to the egg's equator
in which long actin fibres develop in a microtubule-independent manner, and
randomizes the LR orientation of visceral organs in affected tadpoles. The
researchers suggest that the consistent chirality of the BDM-induced twisting
movement reveals a cryptic asymmetry in the egg's cortical actin cytoskeleton
that could play an early role in LR axis determination.
Related articles in Development:
- Intrinsic chiral properties of the Xenopus egg cortex: an early indicator of left-right asymmetry?
- Michael V. Danilchik, Elizabeth E. Brown, and Kristen Riegert
Development 2006 133: 4517-4526.
[Abstract]
[Full Text]
