Timing and mechanism of the initial cue establishing handed left–right asymmetry in Caenorhabditis elegans embryos. Issue 6 (5th March 2014)

• Record Type: Journal Article
• Authors: Schonegg, Stephanie; Hyman, Anthony A.; Wood, William B.
• Other Names: Halpern Marnie E. guestEditor.; Hobert Oliver guestEditor.; Wright Christopher V. E. guestEditor.
• Is Part Of: Genesis. Volume 52:Issue 6(2014:Jun.)
• Page Start: 572
• Page End: 580
• Publication Date: 2014-03-05
• Subjects: chirality -- cleavage furrow initiation -- cortical rotation -- handedness -- symmetry breaking; Developmental genetics -- Periodicals; Genetics -- Periodicals; Developmental biology -- Periodicals; Embryology -- Periodicals; Genetic regulation -- Periodicals; 576.5
• DOI: 10.1002/dvg.22749
• Languages: English
• ISSNs: 1526-954X

Abstract

Summary: By the six‐cell stage, embryos of Caenorhabditis elegans are morphologically L–R asymmetric with an invariant handedness that persists throughout development. We used intracellular markers to ask whether breaking of L–R symmetry could be observed at earlier stages. Observation of two‐ to three‐cell embryos carrying intracellular markers indicated that L–R symmetry is broken concomitantly with establishment of D–V axis polarity during division of the anterior AB cell. The AB cleavage furrow initiates asymmetrically and always from the left, suggesting L–R differences in the AB cell cortex. An invariantly handed cortical rotation observed earlier during first cleavage implies that the one‐cell embryo has an intrinsic chirality. We propose that L–R differences in the cortex could result from mechanical forces on asymmetric components of a chiral cortical network during the off‐axis elongation of the AB‐cell spindle prior to AB cleavage. genesis 52:572–580, 2014. © 2014 Wiley Periodicals, Inc.