PgmNr W4055: Centrosome-cortical contact duration affects anterior-posterior polarity in the one-cell C. elegans embryo.

Authors:
D. M. Saturno; D. Stephens; D. Parikh; E. Jaeger; R. Lyczak


Institutes
Ursinus College, Collegeville, PA.


Keyword: Cell polarization

Abstract:

Anterior-posterior axis establishment occurs in the one-cell C. elegans embryo, triggered by the sperm-donated centrosome. While it is believed that the centrosome can cue polarity from a distance, centrosomes are pushed to contact the cortex during the polarization process. The role for this sustained cortical contact remains an open question. Centrosomes are mislocalized in one-cell pam-1 embryos and polarity establishment fails. This phenotype is rescued however, when centrosomes are made to contact the cortex by inactivating dynein heavy chain. To examine in detail the requirement for centrosome-cortical contact, we used time-lapse confocal imaging of wild-type and pam-1 mutant strains with GFP-tagged centrosome and PAR polarity proteins. We measured timing and duration of contact, as well as centrosome distance from the cortex and correlated these centrosome dynamics with the timing of symmetry breaking and PAR protein localization. We discovered that pam-1 embryos had comparable centrosome-cortical distances from wild-type, but exhibited shorter centrosome-cortex durations. Very short durations in pam-1 correlated with a delay in or lack of symmetry breaking in embryos. In addition, while centrosome distance from the cortex did not affect the extent of PAR localization, we found that duration of centrosome contact made a difference in pam-1 mutants. Shorter duration times correlated with smaller PAR-1 posterior domains. Taken together, these results suggest that centrosome contact is required for robust polarization when pam-1 is absent.



Wormbase Genetic Index
1. pam-1