Cytokinetic bridge triggers de novo lumen formation in vivo

Abstract

Multicellular rosettes are transient epithelial structures that serve as intermediates during diverse organ formation. We have identified a unique contributor to rosette formation in zebrafish Kupffer's vesicle (KV) that requires cell division, specifically the final stage of mitosis termed abscission. KV utilizes a rosette as a prerequisite before forming a lumen surrounded by ciliated epithelial cells. Our studies identify that KV-destined cells remain interconnected by cytokinetic bridges that position at the rosette's center. These bridges act as a landmark for directed Rab11 vesicle motility to deliver an essential cargo for lumen formation, CFTR (cystic fibrosis transmembrane conductance regulator). Here we report that premature bridge cleavage through laser ablation or inhibiting abscission using optogenetic clustering of Rab11 result in disrupted lumen formation. We present a model in which KV mitotic cells strategically place their cytokinetic bridges at the rosette center, where Rab11associated vesicles transport CFTR to aid in lumen establishment.

Coordinated assembly and release of adhesions builds apical junctional belts during de novo polarisation of an epithelial tube

“…During epithelialisation, these defects first resulted in closed lumens ( Figs 3 B and 4 Hi). This is in line with our previous findings ( Buckley et al, 2013 ) and the findings of others that apical localisation of Rab11 is necessary for cell abscission and normal opening of Kupffer's vesicle in zebrafish ( Rathbun et al, 2020 ). It would be interesting to know whether similar mechanisms also operate in the caudal segments of avian and mammalian spinal cord.…”

PLK1- and PLK4-mediated asymmetric mitotic centrosome size and positioning in the early zebrafish embryo

“…Due to this, we tested the hypothesis that PLK1 and/or PLK4 regulate g-tubulin organization at mitotic centrosomes in zebrafish embryos. The PLK1 and PLK4 small molecule inhibitors, BI2536 [10,19,20] and centrinone [21], were injected into 1 cell stage embryos (concentrations used 1µM or 100nM, BI2536 described with zebrafish in [19,20]). An injection approach was utilized versus soaking the embryos in drug due to the low permeability of the zebrafish chorion and embryo fragility at this stage.…”

The recycling endosome protein Rab25 coordinates collective cell movements in the zebrafish surface epithelium

“…In mouse ES cells, abscission impacts cell fate by acting as a switch for pluripotency exit (Chaigne et al, 2020). Lastly, cytokinetic bridges act as landmarks for lumen development in both cell culture and zebrafish, with the timing of abscission critical for successful lumen expansion (Rathbun et al, 2020;Willenborg and Prekeris, 2011). More specifically, in Kupffer's vesicle, the zebrafish leftright laterality organ, premature cytokinetic bridge cutting via laser ablation disrupted lumen morphogenesis (Rathbun et al, 2020).…”

“…Lastly, cytokinetic bridges act as landmarks for lumen development in both cell culture and zebrafish, with the timing of abscission critical for successful lumen expansion (Rathbun et al, 2020;Willenborg and Prekeris, 2011). More specifically, in Kupffer's vesicle, the zebrafish leftright laterality organ, premature cytokinetic bridge cutting via laser ablation disrupted lumen morphogenesis (Rathbun et al, 2020). Open questions include what happens to cells if they remain interconnected by cytokinetic bridges during tissue morphogenesis and do cytokinesis failures hinder cell rearrangements or disrupt tissue-scale forces?…”

“…Recycled membrane is trafficked to the midbody and impaired Rab11 or Rab35 endocytic-recycling pathways result in delayed or failed abscission (Dambournet et al, 2011;Frémont et al, 2018;Frémont et al, 2017;Kouranti et al, 2006). For example, disrupting Rab11 directed trafficking perturbs Kupffer's vesicle morphogenesis during embryonic development in the zebrafish (Rathbun et al, 2020).…”