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

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.

2021 ◽  
Author(s):  
Ido Nir ◽  
Gabriel O Amador ◽  
Yan Gong ◽  
Nicole K Smoot ◽  
Le Cai ◽  
...  

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.


Open Biology ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 200314
Author(s):  
Cuie Chen ◽  
Yukiko M. Yamashita

The centrosome is a unique organelle: the semi-conservative nature of its duplication generates an inherent asymmetry between ‘mother’ and ‘daughter’ centrosomes, which differ in their age. This asymmetry has captivated many cell biologists, but its meaning has remained enigmatic. In the last two decades, many stem cell types have been shown to display stereotypical inheritance of either the mother or daughter centrosome. These observations have led to speculation that the mother and daughter centrosomes bear distinct information, contributing to differential cell fates during asymmetric cell divisions. This review summarizes recent progress and discusses how centrosome asymmetry may promote asymmetric fates during stem cell divisions.


1999 ◽  
Vol 112 (10) ◽  
pp. 1541-1551 ◽  
Author(s):  
M. Tio ◽  
M. Zavortink ◽  
X. Yang ◽  
W. Chia

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.


Cancers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1423 ◽  
Author(s):  
Alexandr Samocha ◽  
Hanna Doh ◽  
Kai Kessenbrock ◽  
Jeroen P. Roose

Fluidity in cell fate or heterogeneity in cell identity is an interesting cell biological phenomenon, which at the same time poses a significant obstacle for cancer therapy. The mammary gland seems a relatively straightforward organ with stromal cells and basal- and luminal- epithelial cell types. In reality, the epithelial cell fates are much more complex and heterogeneous, which is the topic of this review. Part of the complexity comes from the dynamic nature of this organ: the primitive epithelial tree undergoes extensively remodeling and expansion during puberty, pregnancy, and lactation and, unlike most other organs, the bulk of mammary gland development occurs late, during puberty. An active cell biological debate has focused on lineage commitment to basal- and luminal- epithelial cell fates by epithelial progenitor and stem cells; processes that are also relevant to cancer biology. In this review, we discuss the current understanding of heterogeneity in mammary gland and recent insights obtained through lineage tracing, signaling assays, and organoid cultures. Lastly, we relate these insights to cancer and ongoing efforts to resolve heterogeneity in breast cancer with single-cell RNAseq approaches.


2021 ◽  
Vol 22 (13) ◽  
pp. 7043
Author(s):  
Shaida Ouladan ◽  
Alex Gregorieff

Despite the environmental constraints imposed upon the intestinal epithelium, this tissue must perform essential functions such as nutrient absorption and hormonal regulation, while also acting as a critical barrier to the outside world. These functions depend on a variety of specialized cell types that are constantly renewed by a rapidly proliferating population of intestinal stem cells (ISCs) residing at the base of the crypts of Lieberkühn. The niche components and signals regulating crypt morphogenesis and maintenance of homeostatic ISCs have been intensely studied over the last decades. Increasingly, however, researchers are turning their attention to unraveling the mechanisms driving gut epithelial regeneration due to physical damage or infection. It is now well established that injury to the gut barrier triggers major cell fate changes, demonstrating the highly plastic nature of the gut epithelium. In particular, lineage tracing and transcriptional profiling experiments have uncovered several injury-induced stem-cell populations and molecular markers of the regenerative state. Despite the progress achieved in recent years, several questions remain unresolved, particularly regarding the mechanisms driving dedifferentiation of the gut epithelium. In this review, we summarize the latest studies, primarily from murine models, that define the regenerative processes governing the gut epithelium and discuss areas that will require more in-depth investigation.


Cancers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 2407
Author(s):  
Ruicen He ◽  
Arthur Dantas ◽  
Karl Riabowol

Acetylation of histones is a key epigenetic modification involved in transcriptional regulation. The addition of acetyl groups to histone tails generally reduces histone-DNA interactions in the nucleosome leading to increased accessibility for transcription factors and core transcriptional machinery to bind their target sequences. There are approximately 30 histone acetyltransferases and their corresponding complexes, each of which affect the expression of a subset of genes. Because cell identity is determined by gene expression profile, it is unsurprising that the HATs responsible for inducing expression of these genes play a crucial role in determining cell fate. Here, we explore the role of HATs in the maintenance and differentiation of various stem cell types. Several HAT complexes have been characterized to play an important role in activating genes that allow stem cells to self-renew. Knockdown or loss of their activity leads to reduced expression and or differentiation while particular HATs drive differentiation towards specific cell fates. In this study we review functions of the HAT complexes active in pluripotent stem cells, hematopoietic stem cells, muscle satellite cells, mesenchymal stem cells, neural stem cells, and cancer stem cells.


Development ◽  
2000 ◽  
Vol 127 (17) ◽  
pp. 3865-3876
Author(s):  
M.S. Rones ◽  
K.A. McLaughlin ◽  
M. Raffin ◽  
M. Mercola

Notch signaling mediates numerous developmental cell fate decisions in organisms ranging from flies to humans, resulting in the generation of multiple cell types from equipotential precursors. In this paper, we present evidence that activation of Notch by its ligand Serrate apportions myogenic and non-myogenic cell fates within the early Xenopus heart field. The crescent-shaped field of heart mesoderm is specified initially as cardiomyogenic. While the ventral region of the field forms the myocardial tube, the dorsolateral portions lose myogenic potency and form the dorsal mesocardium and pericardial roof (Raffin, M., Leong, L. M., Rones, M. S., Sparrow, D., Mohun, T. and Mercola, M. (2000) Dev. Biol., 218, 326–340). The local interactions that establish or maintain the distinct myocardial and non-myocardial domains have never been described. Here we show that Xenopus Notch1 (Xotch) and Serrate1 are expressed in overlapping patterns in the early heart field. Conditional activation or inhibition of the Notch pathway with inducible dominant negative or active forms of the RBP-J/Suppressor of Hairless [Su(H)] transcription factor indicated that activation of Notch feeds back on Serrate1 gene expression to localize transcripts more dorsolaterally than those of Notch1, with overlap in the region of the developing mesocardium. Moreover, Notch pathway activation decreased myocardial gene expression and increased expression of a marker of the mesocardium and pericardial roof, whereas inhibition of Notch signaling had the opposite effect. Activation or inhibition of Notch also regulated contribution of individual cells to the myocardium. Importantly, expression of Nkx2. 5 and Gata4 remained largely unaffected, indicating that Notch signaling functions downstream of heart field specification. We conclude that Notch signaling through Su(H) suppresses cardiomyogenesis and that this activity is essential for the correct specification of myocardial and non-myocardial cell fates.


Development ◽  
2002 ◽  
Vol 129 (20) ◽  
pp. 4677-4684 ◽  
Author(s):  
Virginie Orgogozo ◽  
François Schweisguth ◽  
Yohanns Bellaïche

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.


Development ◽  
2000 ◽  
Vol 127 (22) ◽  
pp. 4959-4969 ◽  
Author(s):  
E.J. Ward ◽  
J.B. Skeath

The Drosophila heart is a simple organ composed of two major cell types: cardioblasts, which form the simple contractile tube of the heart, and pericardial cells, which flank the cardioblasts. A complete understanding of Drosophila heart development requires the identification of all cell types that comprise the heart and the elucidation of the cellular and genetic mechanisms that regulate the development of these cells. Here, we report the identification of a new population of heart cells: the Odd skipped-positive pericardial cells (Odd-pericardial cells). We have used descriptive, lineage tracing and genetic assays to clarify the cellular and genetic mechanisms that control the development of Odd-pericardial cells. Odd skipped marks a population of four pericardial cells per hemisegment that are distinct from previously identified heart cells. We demonstrate that within a hemisegment, Odd-pericardial cells develop from three heart progenitors and that these heart progenitors arise in multiple anteroposterior locations within the dorsal mesoderm. Two of these progenitors divide asymmetrically such that each produces a two-cell mixed-lineage clone of one Odd-pericardial cell and one cardioblast. The third progenitor divides symmetrically to produce two Odd-pericardial cells. All remaining cardioblasts in a hemisegment arise from two cardioblast progenitors each of which produces two cardioblasts. Furthermore, we demonstrate that numb and sanpodo mediate the asymmetric divisions of the two mixed-lineage heart progenitors noted above.


Development ◽  
2002 ◽  
Vol 129 (20) ◽  
pp. 4843-4853 ◽  
Author(s):  
Qin Shen ◽  
Weimin Zhong ◽  
Yuh Nung Jan ◽  
Sally Temple

Stem cells and neuroblasts derived from mouse embryos undergo repeated asymmetric cell divisions, generating neural lineage trees similar to those of invertebrates. In Drosophila, unequal distribution of Numb protein during mitosis produces asymmetric cell divisions and consequently diverse neural cell fates. We investigated whether a mouse homologue m-numb had a similar role during mouse cortical development. Progenitor cells isolated from the embryonic mouse cortex were followed as they underwent their next cell division in vitro. Numb distribution was predominantly asymmetric during asymmetric cell divisions yielding a β-tubulin III− progenitor and a β-tubulin III+ neuronal cell (P/N divisions) and predominantly symmetric during divisions producing two neurons (N/N divisions). Cells from the numb knockout mouse underwent significantly fewer asymmetric P/N divisions compared to wild type, indicating a causal role for Numb. When progenitor cells derived from early (E10) cortex undergo P/N divisions, both daughters express the progenitor marker Nestin, indicating their immature state, and Numb segregates into the P or N daughter with similar frequency. In contrast, when progenitor cells derived from later E13 cortex (during active neurogenesis in vivo) undergo P/N divisions they produce a Nestin+ progenitor and a Nestin– neuronal daughter, and Numb segregates preferentially into the neuronal daughter. Thus during mouse cortical neurogenesis, as in Drosophila neurogenesis, asymmetric segregation of Numb could inhibit Notch activity in one daughter to induce neuronal differentiation. At terminal divisions generating two neurons, Numb was symmetrically distributed in approximately 80% of pairs and asymmetrically in 20%. We found a significant association between Numb distribution and morphology: most sisters of neuron pairs with symmetric Numb were similar and most with asymmetric Numb were different. Developing cortical neurons with Numb had longer processes than those without. Numb is expressed by neuroblasts and stem cells and can be asymmetrically segregated by both. These data indicate Numb has an important role in generating asymmetric cell divisions and diverse cell fates during mouse cortical development.


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