Int. J. Dev. Biol. 59: 289 - 301 (2015)

https://doi.org/10.1387/ijdb.150209sw

Vol 59, Issue 7-8-9

Special Issue: Ionic Messengers in Development and Cancer

Inhibition of SOCE disrupts cytokinesis in zebrafish embryos via inhibition of cleavage furrow deepening

Published: 19 November 2015

Ching M. Chan¹, Yiyun Chen¹, Tin S. Hung¹, Andrew L. Miller^1,2, Alan M. Shipley³ and Sarah E. Webb*^,1

¹Division of Life Science & State Key Laboratory of Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, PRC, ²MBL, Woods Hole, MA, USA and ³Applicable Electronics LLC, New Haven, CT, USA

Abstract

During the first few cell division cycles in zebrafish, distinct Ca²⁺ transients are localized to the early embryonic cleavage furrows, where they accompany (and are required for) furrow positioning, propagation, deepening and apposition. It has previously been shown that the endoplasmic reticulum (ER) acts as the primary store for generating these Ca²⁺ transients via release through inositol 1,4,5-trisphosphate receptors (IP₃Rs). We hypothesised that maintaining the elevated levels of intracellular Ca²⁺ required for deepening and apposition of the cleavage furrows in these large eggs might result in the depletion of the available ER Ca²⁺ store, thus the role of store-operated Ca²⁺ entry (SOCE) was examined. Newly fertilized, dechorionated embryos were incubated with various SOCE inhibitors, starting just prior to the onset of the first cell division cycle. The effect of these inhibitors on mitosis, furrow positioning, propagation, deepening and apposition, and the generation of the cytokinetic Ca²⁺ transients was determined. Treatment with 2-APB or SKF 96365 had no major effect on mitosis, furrow positioning or propagation, but inhibited furrow deepening resulting in regression of the cleavage furrow. Both of these inhibitors also blocked the furrowing Ca²⁺ transient, with SKF 96365 having a more profound inhibitory effect than 2-APB. In zebrafish, SOCE does not appear to be required for mitosis or the early stages of cytokinesis during the early embryonic cell division cycles, but it does appear to be essential for maintaining the elevated levels of [Ca²⁺]_i for the extended periods that are required during furrow deepening and daughter cell apposition.

Keywords

aequorin, cytokinesis, Ca²⁺ signalling, store-operated Ca²⁺ entry, zebrafish embryo