Centrosome-dependent asymmetric inheritance of the midbody ring in Drosophila germline stem cell division

We report here that two distinct centriole lineages exist in Drosophila: somatic centrioles usually composed by microtubule doublets and germ line centrioles characterized by triplets. Remarkably, the transition from doublets to triplets in the testis occurs within the stem cell niche with the formation of the C-tubule. We demonstrated that the old mother centriole that stays in the apical cytoplasm of the male germline stem cells (GSCs) is invariably composed by triplets, whereas its daughter is always built by mixed doublets and triplets. This difference represents the first documentation of a structural asymmetry between mother and daughter centrioles in Drosophila GSCs and may reflect a correlation between the architecture of parent centrioles and their ability to recruit centrosomal proteins. We also found that the old mother centriole is linked to the cell membrane by distinct projections that may play an important role in keeping its apical position during centrosome separation.

Section: Transition From Doublets To Triplets -The Stem Cell Nichementioning

confidence: 99%

The Drosophila centriole: conversion of doublets to triplets within the stem cell niche

Gottardo

Callaini

Riparbelli

2015

“…However, very recent observations indicate that the MBR is actually engulfed after abscission (Ou et al, 2014;Singh and Pohl, 2014). MBR engulfment is also presumably observed in specific divisions of male germline cells in Drosophila (Salzmann et al, 2014). Taken together, these data suggest that, rather than being the exception, MBR engulfment is a distinct and evolutionarily conserved phenomenon.…”

Section: Midbody Remnant Engulfment Involves Cell Surface Receptorsmentioning

confidence: 77%

“…Similarly, in male germline, the MBRs produced from the spermatogonial divisions associate with nonsister cyst cells (Salzmann et al, 2014). Thus, MBRs likely display particular signals that are recognized by specific cell receptors in a wide range of organisms.…”

Section: Midbody Remnant Engulfment Involves Cell Surface Receptorsmentioning

confidence: 99%

Midbody remnant engulfment after cytokinesis abscission in mammalian cells

Crowell

Gaffuri

Gayraud-Morel

et al. 2014

109

BSTRACTThe midbody remnant (MBR) that is generated after cytokinetic abscission has recently attracted a lot of attention, because it might have crucial consequences for cell differentiation and tumorigenesis in mammalian cells. In these cells, it has been reported that the MBR is either released into the extracellular medium or retracted into one of the two daughter cells where it can be degraded by autophagy. Here, we describe a major alternative pathway in a variety of human and mouse immortalized cells, cancer cells and primary stem cells. Using correlative light and scanning electron microscopy and quantitative assays, we found that sequential abscissions on both sides of the midbody generate free MBRs, which are tightly associated with the cell surface through a Ca 2+ /Mg 2+ -dependent receptor. Surprisingly, MBRs move over the cell surface for several hours, before being eventually engulfed by an actin-dependent phagocytosis-like mechanism. Mathematical modeling combined with experimentation further demonstrates that lysosomal activities fully account for the clearance of MBRs after engulfment. This study changes our understanding of how MBRs are inherited and degraded in mammalian cells and suggests a mechanism by which MBRs might signal over long distances between cells.

“…Nonetheless, Drosophila male germline stem cells exclude the midbody ring, whereas female germline stem cells inherit it. Thus, at least in Drosophila germline lineages, which are a stereotypical example for asymmetric inheritance of midbody rings, they are not dictating stem cell identity (Salzmann et al, 2014). Although the possible functions outlined above are based primarily on correlative evidence, recent work in C. elegans embryos has directly revealed that the asymmetric positioning of midbody remnants mediates part of the dorsoventral axis formation (Singh and Pohl, 2014).…”

Section: En Route To Abscission -The Final Cutmentioning

confidence: 99%

Epithelial cell division – multiplying without losing touch

Bras

Borgne

2014

Epithelia are compact tissues comprising juxtaposed cells that function as mechanical and chemical barriers between the body and the environment. This barrier relies, in part, on adhesive contacts within adherens junctions, which are formed and stabilized by Ecadherin and catenin proteins linked to the actomyosin cytoskeleton. During development and throughout adult life, epithelia are continuously growing or regenerating, largely as a result of cell division. Although persistence of adherens junctions is needed for epithelial integrity, these junctions are continually remodelled during cell division. In this Commentary, we will focus on cytokinesis, the final step of mitosis, a multiparty phenomenon in which the adherens junction belt plays an essential role and during which a new cell-cell interface is generated between daughter cells. This new interface is the site of intense remodelling, where new adhesive contacts are assembled and cell polarity is transmitted from mother to daughter cells, ultimately becoming the site of cell signalling.