Par6 regulates skeletogenesis and gut differentiation in sea urchin larvae

Shiomi, Kosuke; Yamazaki, Atsuko; Kagawa, Mitsuyoshi; Kiyomoto, Masato; Yamaguchi, Masatoshi

doi:10.1007/s00427-012-0409-5

Cited by 4 publications

(4 citation statements)

References 36 publications

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“…These phenotypes caused by Arf6 perturbation that were observed in our study are reminiscent to those caused by Par6 knockdown in the sea urchin embryos, including impaired skeletogenesis and gut differentiation (Shiomi et al, 2012). In sea urchin embryos, Par6-aPKC complex mediates cell polarity in the early embryo which impact later developmental stages (Alford et al, 2009; Moorhouse et al, 2015).…”

Section: Discussionsupporting

confidence: 62%

The small GTPase Arf6 regulates sea urchin morphogenesis

et al. 2017

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The small GTPase Arf6 is a conserved protein that is expressed in all metazoans. Arf6 remodels cytoskeletal actin and mediates membrane protein trafficking between the plasma membrane in its active form and endosomal compartments in its inactive form. While a rich knowledge exists for the cellular functions of Arf6, relatively little is known about its physiological role in development. This study examines the function of Arf6 in mediating cellular morphogenesis in early development. We dissect the function of Arf6 with a loss-of-function morpholino and constitutively active Arf6-Q67L construct. We focus on the two cell types that undergo active directed migration: the primary mesenchyme cells (PMCs) that give rise to the sea urchin skeleton and endodermal cells that form the gut. Our results indicate that Arf6 plays an important role in skeleton formation and PMC migration, in part due to its ability to remodel actin. We also found that embryos injected with Arf6 morpholino have gastrulation defects and embryos injected with constitutively active Arf6 have endodermal cells detached from the gut epithelium with decreased junctional cadherin staining, indicating that Arf6 may mediate the recycling of cadherin. Thus, Arf6 impacts cells that undergo coordinated movement to form embryonic structures in the developing embryo.

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Section: Discussionsupporting

confidence: 62%

The small GTPase Arf6 regulates sea urchin morphogenesis

et al. 2017

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“…However, we feel this is unlikely given its membership in the M9 and the fact that its expression is high in osteoblasts and its expression differs as a function of osteoblast differentiation. In addition, Par6 has recently been shown to be involved in skeletogenesis and biomineralization in the sea urchin [47]. Although more work is needed it is tempting to speculate that Pard6g is involved in Wnt signaling.…”

Section: Discussionmentioning

confidence: 99%

Systems Genetic Analysis of Osteoblast-Lineage Cells

et al. 2012

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The osteoblast-lineage consists of cells at various stages of maturation that are essential for skeletal development, growth, and maintenance. Over the past decade, many of the signaling cascades that regulate this lineage have been elucidated; however, little is known of the networks that coordinate, modulate, and transmit these signals. Here, we identify a gene network specific to the osteoblast-lineage through the reconstruction of a bone co-expression network using microarray profiles collected on 96 Hybrid Mouse Diversity Panel (HMDP) inbred strains. Of the 21 modules that comprised the bone network, module 9 (M9) contained genes that were highly correlated with prototypical osteoblast maker genes and were more highly expressed in osteoblasts relative to other bone cells. In addition, the M9 contained many of the key genes that define the osteoblast-lineage, which together suggested that it was specific to this lineage. To use the M9 to identify novel osteoblast genes and highlight its biological relevance, we knocked-down the expression of its two most connected “hub” genes, Maged1 and Pard6g. Their perturbation altered both osteoblast proliferation and differentiation. Furthermore, we demonstrated the mice deficient in Maged1 had decreased bone mineral density (BMD). It was also discovered that a local expression quantitative trait locus (eQTL) regulating the Wnt signaling antagonist Sfrp1 was a key driver of the M9. We also show that the M9 is associated with BMD in the HMDP and is enriched for genes implicated in the regulation of human BMD through genome-wide association studies. In conclusion, we have identified a physiologically relevant gene network and used it to discover novel genes and regulatory mechanisms involved in the function of osteoblast-lineage cells. Our results highlight the power of harnessing natural genetic variation to generate co-expression networks that can be used to gain insight into the function of specific cell-types.

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“…Furthermore, the down regulation of the expression of these proteins in the archenteron may reflect a functional significance as they may be more actively involved in the formation and maintenance of the epithelium that is formed at the blastula stage. Recent data, however, has found the PAR6 regulates skeletogenesis and gut differentation in the Hemicentrotus pulcherrimus species of sea urchin (Shiomi et al, ). Inhibition of aPKC did not appear to affect archenteron ingression or spicule formation in the Paracentrotus lividus species of sea urchin (Pruliere et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…Although the PAR proteins have been examined across a wide variety of species, it was not until recently that they were explored in sea urchins (Shiomi and Yamaguchi, ; Alford et al, ; Pruliere et al, ; Shiomi et al, ). PAR6, aPKC, and CDC42 all localize to the apical cortex as early as the 2‐cell stage of development in these embryos and this apical polarity was found to be functional, as endocytosis was only observed on the apical surface even upon dissociation of the blastomeres (Alford et al, ).…”

Section: Introductionmentioning

confidence: 99%

Influence of cell polarity on early development of the sea urchin embryo

Moorhouse

Gudejko

McDougall

et al. 2015

Developmental Dynamics

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Background Establishment and maintenance of cell polarity is critical for normal embryonic development. Previously, it was thought that the echinoderm embryo remained relatively unpolarized until the first asymmetric division at the 16 cell stage. Here we analyzed roles of the cell polarity regulators, the PAR complex proteins, and how their disruption in early development affects later developmental milestones. Results We found that PAR6, aPKC and CDC42 localize to the apical cortex as early as the 2 cell stage and that this localization is retained through the gastrula stage. Interestingly, PAR1 also colocalizes with these apical markers through the gastrula stage. Additionally, PAR1 was found to be in complex with aPKC, but not PAR6. PAR6, aPKC, and CDC42 are anchored in the cortical actin cytoskeleton by assembled myosin. Furthermore, assembled myosin was found to be necessary to maintain proper PAR6 localization through subsequent cleavage divisions. Interference with myosin assembly prevented the embryos from reaching the blastula stage, while transient disruptions of either actin or microtubules did not have this effect. Conclusions These observations suggest that disruptions of the polarity in the early embryo can have a significant impact on the ability of the embryo to reach later critical stages in development.

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Par6 regulates skeletogenesis and gut differentiation in sea urchin larvae

Cited by 4 publications

References 36 publications

The small GTPase Arf6 regulates sea urchin morphogenesis

The small GTPase Arf6 regulates sea urchin morphogenesis

Systems Genetic Analysis of Osteoblast-Lineage Cells

Influence of cell polarity on early development of the sea urchin embryo

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