A functional analysis of inscuteable and its roles during Drosophila asymmetric cell divisions

1999 ◽  
Vol 112 (10) ◽  
pp. 1541-1551 ◽  
Author(s):  
M. Tio ◽  
M. Zavortink ◽  
X. Yang ◽  
W. Chia
Keyword(s):  
Cell Fate ◽  
Mitotic Spindle ◽  
Mother Cell ◽  
Apical Cell ◽  
Cell Cortex ◽  
Asymmetric Cell Divisions ◽  
Cell Divisions ◽  
Asymmetric Divisions ◽  
Necessary And Sufficient ◽  
Ganglion Mother Cell

Cellular diversity in the Drosophila central nervous system is generated through a series of asymmetric cell divisions in which one progenitor produces two daughter cells with distinct fates. Asymmetric basal cortical localisation and segregation of the determinant Prospero during neuroblast cell divisions play a crucial role in effecting distinct cell fates for the progeny sibling neuroblast and ganglion mother cell. Similarly asymmetric localisation and segregation of the determinant Numb during ganglion mother cell divisions ensure that the progeny sibling neurons attain distinct fates. The most upstream component identified so far which acts to organise both neuroblast and ganglion mother cell asymmetric divisions is encoded by inscuteable. The Inscuteable protein is itself asymmetrically localised to the apical cell cortex and is required both for the basal localisation of the cell fate determinants during mitosis and for the orientation of the mitotic spindle along the apical/basal axis. Here we define the functional domains of Inscuteable. We show that aa252-578 appear sufficient to effect all aspects of its function, however, the precise requirements for its various functions differ. The region, aa288-497, is necessary and sufficient for apical cortical localisation and for mitotic spindle (re)orientation along the apical/basal axis. A larger region aa288-540 is necessary and sufficient for asymmetric Numb localisation and segregation; however, correct localisation of Miranda and Prospero requires additional sequences from aa540-578. The requirement for the resolution of distinct sibling neuronal fates appears to coincide with the region necessary and sufficient for Numb localisation (aa288-540). Our data suggest that apical localisation of the Inscuteable protein is a necessary prerequisite for all other aspects of its function. Finally, we show that although inscuteable RNA is normally apically localised, RNA localisation is not required for protein localisation or any aspects of inscuteable function.

Inscuteable-dependent apical localization of the microtubule-binding protein Cornetto suggests a role in asymmetric cell division

2001 ◽  
Vol 114 (20) ◽  
pp. 3655-3662 ◽  
Author(s):  
Silvia Bulgheresi ◽  
Elke Kleiner ◽  
Juergen A. Knoblich
Keyword(s):  
Cell Fate ◽  
Mitotic Spindle ◽  
Binding Protein ◽  
Protein Localization ◽  
Apical Cell ◽  
Coiled Coil ◽  
Cell Cortex ◽  
Dependent Manner ◽  
Genetic Redundancy ◽  
Microtubule Binding

Drosophila neuroblasts divide asymmetrically along the apical-basal axis. The Inscuteable protein localizes to the apical cell cortex in neuroblasts from interphase to metaphase, but disappears in anaphase. Inscuteable is required for correct spindle orientation and for asymmetric localization of cell fate determinants to the opposite (basal) cell cortex. Here, we show that Inscuteable also directs asymmetric protein localization to the apical cell cortex during later stages of mitosis. In a two-hybrid screen for Inscuteable-binding proteins, we have identified the coiled-coil protein Cornetto, which shows a highly unusual subcellular distribution in neuroblasts. Although the protein is uniformly distributed in the cytoplasm during metaphase, it concentrates apically in anaphase and forms an apical crescent during telophase in an inscuteable-dependent manner. Upon overexpression, Cornetto localizes to astral microtubules and microtubule spin-down experiments demonstrate that Cornetto is a microtubule-binding protein. After disruption of the actin cytoskeleton, Cornetto localizes with microtubules throughout the cell cycle and decorates the mitotic spindle during metaphase. Our results reveal a novel pattern of asymmetric protein localization in Drosophila neuroblasts and are consistent with a function of Cornetto in anchoring the mitotic spindle during late phases of mitosis, even though our cornetto mutant analysis suggests that this function might be obscured by genetic redundancy.

Binary cell death decision regulated by unequal partitioning of Numb at mitosis

Development ◽  
2002 ◽  
Vol 129 (20) ◽  
pp. 4677-4684 ◽  
Author(s):  
Virginie Orgogozo ◽  
François Schweisguth ◽  
Yohanns Bellaïche
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Daughter Cell ◽  
Asymmetric Cell Divisions ◽  
Daughter Cells ◽  
Cell Divisions ◽  
Specific Manner ◽  
Asymmetric Divisions ◽  
Apoptotic Genes ◽  
Necessary And Sufficient

An important issue in Metazoan development is to understand the mechanisms that lead to stereotyped patterns of programmed cell death. In particular, cells programmed to die may arise from asymmetric cell divisions. The mechanisms underlying such binary cell death decisions are unknown. We describe here a Drosophila sensory organ lineage that generates a single multidentritic neuron in the embryo. This lineage involves two asymmetric divisions. Following each division, one of the two daughter cells expresses the pro-apoptotic genes reaper and grim and subsequently dies. The protein Numb appears to be specifically inherited by the daughter cell that does not die. Numb is necessary and sufficient to prevent apoptosis in this lineage. Conversely, activated Notch is sufficient to trigger death in this lineage. These results show that binary cell death decision can be regulated by the unequal segregation of Numb at mitosis. Our study also indicates that regulation of programmed cell death modulates the final pattern of sensory organs in a segment-specific manner.

scholarly journals Conservation and Divergence of YODA MAPKKK Function in Regulation of Grass Epidermal Patterning

2018 ◽  
Author(s):  
Emily Abrash ◽  
M Ximena Anleu Gil ◽  
Juliana L Matos ◽  
Dominique C Bergmann
Keyword(s):  
Cell Fate ◽  
Cell Types ◽  
Lineage Tracing ◽  
Cell Fates ◽  
Kinase Gene ◽  
Asymmetric Cell Divisions ◽  
Cell Divisions ◽  
Asymmetric Divisions ◽  
Species Specific ◽  
Multicellular Organisms

AbstractAll multicellular organisms must properly pattern cell types to generate functional tissues and organs. The organized and predictable cell lineages of the Brachypodium leaf enabled us to characterize the role of the MAPK kinase kinase gene BdYODA1 in regulating asymmetric cell divisions. We find that YODA genes promote normal stomatal spacing patterns in both Arabidopsis and Brachypodium, despite species-specific differences in those patterns. Using lineage tracing and cell fate markers, we show that, unexpectedly, patterning defects in bdyoda1 mutants do not arise from faulty physical asymmetry in cell divisions but rather from improper enforcement of alternative cellular fates after division. These cross-species comparisons allow us to refine our interpretations of MAPK activities during plant asymmetric cell divisions.Summary StatementAnalysis of Brachypodium leaf epidermis development reveals that the MAPKKK, BdYODA1, regulates asymmetric divisions by enforcing resultant cell fates rather than driving initial physical asymmetries.

scholarly journals Spindle orientation and epidermal morphogenesis

2013 ◽  
Vol 368 (1629) ◽  
pp. 20130016 ◽  
Author(s):  
Anita Kulukian ◽  
Elaine Fuchs
Keyword(s):  
Stem Cells ◽  
Basement Membrane ◽  
Cell Fate ◽  
Mitotic Spindle ◽  
Spindle Orientation ◽  
Asymmetric Cell Divisions ◽  
Daughter Cells ◽  
Cell Divisions ◽  
Molecular Machinery ◽  
Asymmetric Partitioning

Asymmetric cell divisions (ACDs) result in two unequal daughter cells and are a hallmark of stem cells. ACDs can be achieved either by asymmetric partitioning of proteins and organelles or by asymmetric cell fate acquisition due to the microenvironment in which the daughters are placed. Increasing evidence suggests that in the mammalian epidermis, both of these processes occur. During embryonic epidermal development, changes occur in the orientation of the mitotic spindle in relation to the underlying basement membrane. These changes are guided by conserved molecular machinery that is operative in lower eukaryotes and dictates asymmetric partitioning of proteins during cell divisions. That said, the shift in spindle alignment also determines whether a division will be parallel or perpendicular to the basement membrane, and this in turn provides a differential microenvironment for the resulting daughter cells. Here, we review how oriented divisions of progenitors contribute to the development and stratification of the epidermis.

scholarly journals On the edge: Evolution of polarity protein BASL and the capacity for stomatal lineage asymmetric divisions

2021 ◽  
Author(s):  
Ido Nir ◽  
Gabriel O Amador ◽  
Yan Gong ◽  
Nicole K Smoot ◽  
Le Cai ◽  
...  
Keyword(s):  
Cell Fate ◽  
Cell Types ◽  
Cell Fates ◽  
Division Plane ◽  
Asymmetric Cell Divisions ◽  
Cell Divisions ◽  
Distinct Cell ◽  
Asymmetric Divisions ◽  
Stem Cell Divisions ◽  
Stomatal Lineage

Asymmetric and oriented stem cell divisions enable the continued production of patterned tissues. The molecules that guide these divisions include several polarity proteins that are localized to discrete plasma membrane domains, are differentially inherited during asymmetric divisions, and whose scaffolding activities can guide division plane orientation and subsequent cell fates. In the stomatal lineages on the surfaces of plant leaves, asymmetric and oriented divisions create distinct cell types in physiologically optimized patterns. The polarity protein BASL is a major regulator of stomatal lineage division and cell fate asymmetries in Arabidopsis, but its role in the stomatal lineages of other plants was unclear. Here, using phylogenetic and functional assays, we demonstrate that BASL is a dicot specific polarity protein. Among dicots, divergence in BASLs roles may reflect some intrinsic protein differences, but more likely reflects previously unappreciated differences in how asymmetric cell divisions are employed for pattern formation in different species. This multi-species analysis therefore provides insight into the evolution of a unique polarity regulator and into the developmental choices available to cells as they build and pattern tissues.

The maternal genespn-4encodes a predicted RRM protein required for mitotic spindle orientation and cell fate patterning in earlyC. elegansembryos

Development ◽  
2001 ◽  
Vol 128 (21) ◽  
pp. 4301-4314 ◽  
Author(s):  
José-Eduardo Gomes ◽  
Sandra E. Encalada ◽  
Kathryn A. Swan ◽  
Christopher A. Shelton ◽  
J. Clayton Carter ◽  
...  
Keyword(s):  
Cell Fate ◽  
Mitotic Spindle ◽  
Pdz Domain ◽  
Early Embryo ◽  
Embryonic Cell ◽  
Rna Recognition Motif ◽  
Rna Recognition ◽  
Asymmetric Cell Divisions ◽  
C Elegans ◽  
Cell Divisions

C. elegans embryogenesis begins with a stereotyped sequence of asymmetric cell divisions that are largely responsible for establishing the nematode body plan. These early asymmetries are specified after fertilization by the widely conserved, cortically enriched PAR and PKC-3 proteins, which include three kinases and two PDZ domain proteins. During asymmetric cell divisions in the early embryo, centrosome pairs initially are positioned on transverse axes but then rotate to align with the anteroposterior embryonic axis. We show that rotation of the centrosomal/nuclear complex in an embryonic cell called P1 requires a maternally expressed gene we name spn-4. The predicted SPN-4 protein contains a single RNA recognition motif (RRM), and belongs to a small subfamily of RRM proteins that includes one Drosophila and two human family members. Remarkably, in mutant embryos lacking spn-4 function the transversely oriented ‘P1’ mitotic spindle appears to re-specify the axis of cell polarity, and the division remains asymmetric. spn-4 also is required for other developmental processes, including the specification of mesendoderm, the restriction of mesectoderm fate to P1 descendants, and germline quiescence during embryogenesis. We suggest that SPN-4 post-transcriptionally regulates the expression of multiple developmental regulators. Such SPN-4 targets might then act more specifically to generate a subset of the anterior-posterior asymmetries initially specified after fertilization by the more generally required PAR and PKC-3 proteins.

scholarly journals LGN regulates mitotic spindle orientation during epithelial morphogenesis

2010 ◽  
Vol 189 (2) ◽  
pp. 275-288 ◽  
Author(s):  
Zhen Zheng ◽  
Huabin Zhu ◽  
Qingwen Wan ◽  
Jing Liu ◽  
Zhuoni Xiao ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Mdck Cells ◽  
Apical Cell ◽  
Cell Polarization ◽  
Epithelial Morphogenesis ◽  
Spindle Orientation ◽  
Cell Cortex ◽  
Dividing Cells ◽  
Cortical Localization ◽  
Lateral Cell

Coordinated cell polarization and mitotic spindle orientation are thought to be important for epithelial morphogenesis. Whether spindle orientation is indeed linked to epithelial morphogenesis and how it is controlled at the molecular level is still unknown. Here, we show that the NuMA- and Gα-binding protein LGN is required for directing spindle orientation during cystogenesis of MDCK cells. LGN localizes to the lateral cell cortex, and is excluded from the apical cell cortex of dividing cells. Depleting LGN, preventing its cortical localization, or disrupting its interaction with endogenous NuMA or Gα proteins all lead to spindle misorientation and abnormal cystogenesis. Moreover, artificial mistargeting of endogenous LGN to the apical membrane results in a near 90° rotation of the spindle axis and profound cystogenesis defects that are dependent on cell division. The normal apical exclusion of LGN during mitosis appears to be mediated by atypical PKC. Thus, cell polarization–mediated spatial restriction of spindle orientation determinants is critical for epithelial morphogenesis.

scholarly journals Quantitative and dynamic cell polarity tracking in plant cells

2020 ◽  
Author(s):  
Yan Gong ◽  
Rachel Varnau ◽  
Eva-Sophie Wallner ◽  
Dominique C. Bergmann ◽  
Lily S. Cheung
Keyword(s):  
Cell Fate ◽  
Cell Polarity ◽  
Brachypodium Distachyon ◽  
Quantitative Information ◽  
Tissue Level ◽  
Asymmetric Cell Divisions ◽  
Cell Divisions ◽  
Versatile Tool ◽  
Dynamic Cell ◽  
Microscopy Techniques

ABSTRACTQuantitative information on the spatiotemporal distribution of polarized proteins is central for understanding cell-fate determination, yet collecting sufficient data for statistical analysis is difficult to accomplish with manual measurements. Here we present POME, a semi-automated pipeline for the quantification of cell polarity, and demonstrate its application to a variety of developmental contexts. POME analysis reveals that during asymmetric cell divisions in the Arabidopsis thaliana stomatal lineage, polarity proteins BASL and BRXL2 are more asynchronous and less mutually dependent than previously thought. While their interaction is important to maintain their polar localization and recruit other effectors to regulate asymmetric cell divisions, BRXL2 polarization precedes that of BASL and can be initiated in BASL’s absence. Uncoupling of polarization from BASL activity is also seen in Brachypodium distachyon, where we find that the MAPKKK BdYDA1 is segregated and polarized following asymmetric division. Our results demonstrate that POME is a versatile tool, which by itself or combined with tissue-level studies and advanced microscopy techniques can help uncover new mechanisms of cell polarity.

scholarly journals The prospero transcription factor is asymmetrically localized to the cell cortex during neuroblast mitosis in Drosophila

Development ◽  
1995 ◽  
Vol 121 (10) ◽  
pp. 3187-3195 ◽  
Author(s):  
E.P. Spana ◽  
C.Q. Doe
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Cell Fate ◽  
Daughter Cell ◽  
Cell Cortex ◽  
Cell Fates ◽  
Extrinsic Factors ◽  
Cortical Localization ◽  
Ganglion Mother Cell ◽  
Intrinsic And Extrinsic Factors

Both intrinsic and extrinsic factors are known to regulate sibling cell fate. Here we describe a novel mechanism for the asymmetric localization of a transcription factor to one daughter cell at mitosis. The Drosophila CNS develops from asymmetrically dividing neuroblasts, which give rise to a large neuroblast and a smaller ganglion mother cell (GMC). The prospero gene encodes a transcription factor necessary for proper GMC gene expression. We show that the prospero protein is synthesized in the neuroblast where it is localized to the F-actin cell cortex. At mitosis, prospero is asymmetrically localized to the budding GMC and excluded from the neuroblast. After cytokinesis, prospero is translocated from the GMC cortex into the nucleus. Asymmetric cortical localization of prospero in neuroblasts requires entry into mitosis; it does not depend on numb function. prospero is also observed in cortical crescents in dividing precursors of the peripheral nervous system and adult midgut. The asymmetric cortical localization of prospero at mitosis is a mechanism for rapidly establishing distinct sibling cell fates in the CNS and possibly other tissues.

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