PT  - JOURNAL ARTICLE
AU  - AM Silva
AU  - D Osório
AU  - AJ Pereira
AU  - H Maiato
AU  - IM Pinto
AU  - B Rubinstein
AU  - R Gassmann
AU  - IA Telley
AU  - AX Carvalho
TI  - Robust Gap Repair in the Contractile Ring Ensures Timely Completion of Cytokinesis
AID  - 10.1101/052704
DP  - 2016 Jan 01
TA  - bioRxiv
PG  - 052704
4099  - http://biorxiv.org/content/early/2016/05/21/052704.short
4100  - http://biorxiv.org/content/early/2016/05/21/052704.full
AB  - Cytokinesis in animal cells requires the constriction of an actomyosin contractile ring, whose architecture and mechanism remain poorly understood. We use laser microsurgery to explore the biophysical properties of constricting contractile rings in C. elegans embryos. Laser cutting causes rings to snap open, which is a sign of tension release. However, instead of disintegrating, ring topology recovers and constriction proceeds. In response to severing, a finite gap forms that is proportional to ring perimeters before cutting, demonstrating that tension along the ring decreases throughout constriction. Severed rings repair their gaps by recruiting new material and subsequently increase constriction rate and complete cytokinesis with the same timing as uncut rings. Rings repair successive cuts and exhibit substantial constriction when gap repair is prevented. Our analysis suggests that cytokinesis is accomplished by contractile modules that assemble and contract autonomously, enabling local repair of the actomyosin network throughout constriction. Consequently, cytokinesis is a highly robust process impervious to discontinuities in contractile ring structure.CIconfidence interval