The mac1 Mutation Alters the Developmental Fate of the Hypodermal Cells and Their Cellular Progeny in the Maize Anther

Abstract In angiosperm ovules and anthers, the hypodermal cell layer provides the progenitors of meiocytes. We have previously reported that the multiple archesporial cells1 (mac1) mutation identifies a gene that plays an important role in the switch of the hypodermal cells from the vegetative pathway to the meiotic (sporogenous) pathway in maize ovules. Here we report that the mac1 mutation alters the developmental fate of the hypodermal cells of the maize anther. In a normal anther a hypodermal cell divides periclinally with the inner cell giving rise to the sporogenous archesporial cells while the outer cell, together with adjacent cells, forms the primary parietal layer. The cells of the parietal layer then undergo two cycles of periclinal divisions to give rise to three wall layers. In mac1 anthers the primary parietal layer usually fails to divide periclinally so that the three wall layers do not form, while the archesporial cells divide excessively and most fail to form microsporocytes. The centrally located mutant microsporocytes are abnormal in appearance and in callose distribution and they fail to proceed through meiosis. These failures in development and function appear to reflect the failure of mac1 gene function in the hypodermal cells and their cellular progeny.

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Embryonic development of the heart

Development ◽

10.1242/dev.22.3.333 ◽

1969 ◽

Vol 22 (3) ◽

pp. 333-348

Author(s):

Francis J. Manasek

Keyword(s):

Cell Layer ◽

Embryonic Heart ◽

Outer Cell ◽

Chick Embryos ◽

Myocardial Wall ◽

Undifferentiated Cells ◽

Epicardial Layer ◽

Outer Cell Layer ◽

Heart Wall

The mature heart may be thought of as consisting of three layers, endocardium, myocardium, and an outer investing tissue called the epicardium. During early formation of the tubular heart of chick embryos, at about the 8-somite stage, two tissue layers become clearly discernible with the light microscope: the endocardium and the developing myocardial wall. The outer epicardial layer does not appear until later in development. It is generally accepted that embryonic heart wall or ‘epimyocardium’ is composed of muscle and undifferentiated cells. As its name implies, the epimyocardium is thought to give rise to myocardium and epicardium. Kurkiewicz (1909) suggested that the epicardium was not an epimyocardial derivative but rather is formed from cells originating in the sinus venosus region, which migrate over the surface of the heart. Nevertheless, it has become generally accepted that the outer cell layer of the embryonic heart wall differentiates in situ to give rise to the definitive visceral epicardium (Patten, 1953).

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Immunohistochemical Characterization of Phosphorylated Ubiquitin in the Mouse Hippocampus

10.1101/2020.01.20.912238 ◽

2020 ◽

Author(s):

Kosuke Kataoka ◽

Andras Bilkei-Gorzo ◽

Andreas Zimmer ◽

Toru Asahi

Keyword(s):

Cell Layer ◽

Granule Cell Layer ◽

Phosphatase And Tensin Homolog ◽

Neuronal Markers ◽

Tensin Homolog ◽

Evolutionarily Conserved ◽

Previous Hypothesis ◽

Mouse Hippocampus ◽

And Function

ABSTRACTMitochondrial autophagy (mitophagy) is an essential and evolutionarily conserved process that maintains mitochondrial integrity via the removal of damaged or superfluous mitochondria in eukaryotic cells. Phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1) and Parkin promote mitophagy and function in a common signaling pathway. PINK1-mediated ubiquitin phosphorylation at Serine 65 (Ser65-pUb) is a key event in the efficient execution of PINK1/Parkin-dependent mitophagy. However, few studies have used immunohistochemistry to analyze Ser65-pUb in the mouse. Here, we examined the immunohistochemical characteristics of Ser65-pUb in the mouse hippocampus. Some hippocampal cells were Ser65-pUb positive, whereas the remaining cells expressed no or low levels of Ser65-pUb. PINK1 deficiency resulted in a decrease in the density of Ser65-pUb-positive cells, consistent with a previous hypothesis based on in vitro research. Interestingly, Ser65-pUb-positive cells were detected in hippocampi lacking PINK1 expression. The CA3 pyramidal cell layer and the dentate gyrus (DG) granule cell layer exhibited significant reductions in the density of Ser65-pUb-positive cells in PINK1-deficient mice. Moreover, Ser65-pUb immunoreactivity colocalized predominantly with neuronal markers. These findings suggest that Ser65-pUb may serve as a biomarker of in situ PINK1 signaling in the mouse hippocampus; however, the results should be interpreted with caution, as PINK1 deficiency downregulated Ser65-pUb only partially.

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A class act: conservation of homeodomain protein functions

Development ◽

10.1242/dev.1994.supplement.61 ◽

1994 ◽

Vol 1994 (Supplement) ◽

pp. 61-77 ◽

Cited By ~ 2

Author(s):

J. Robert Manak ◽

Matthew P. Scott

Keyword(s):

Gene Function ◽

Target Genes ◽

Hox Genes ◽

Homeobox Gene ◽

Homeodomain Protein ◽

Animal Development ◽

Protein Functions ◽

Unified View ◽

Protein Classes ◽

And Function

Dramatic successes in identifying vertebrate homeobox genes closely related to their insect relatives have led to the recognition of classes within the homeodomain superfamily. To what extent are the homeodomain protein classes dedicated to specific functions during development? Although information on vertebrate gene functions is limited, existing evidence from mice and nematodes clearly supports conservation of function for the Hox genes. Less compelling, but still remarkable, is the conservation of other homeobox gene classes and of regulators of homeotic gene expression and function. It is too soon to say whether the cases of conservation are unique and exceptional, or the beginning of a profoundly unified view of gene regulation in animal development. In any case, new questions are raised by the data: how can the differences between mammals and insects be compatible with conservation of homeobox gene function? Did the evolution of animal form involve a proliferation of new homeodomain proteins, new modes of regulation of existing gene types, or new relationships with target genes, or is evolutionary change largely the province of other classes of genes? In this review, we summarize what is known about conservation of homeobox gene function.

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Expression and function of brain-derived neurotrophin factor and its receptor, TrkB, in ovarian follicles from the domestic hen (Gallus gallus domesticus)

Journal of Experimental Biology ◽

10.1242/jeb.204.12.2087 ◽

2001 ◽

Vol 204 (12) ◽

pp. 2087-2095 ◽

Cited By ~ 1

Author(s):

T. Jensen ◽

A. L. Johnson

Keyword(s):

Granulosa Cell ◽

Granulosa Cells ◽

Cell Layer ◽

Preliminary Evidence ◽

Neurotrophin Receptor ◽

Bdnf Mrna ◽

Preovulatory Follicles ◽

Layer Increase ◽

Theca Interna ◽

And Function

SUMMARY This report summarizes patterns of mRNA expression for the brain-derived neurotrophic factor (BDNF) together with its high-affinity neurotrophin receptor trkB within the hen ovary during follicle development, describes hormonal mechanisms for the regulation of trkB gene expression and provides preliminary evidence for a novel function for BDNF-mediated TrkB signaling within the granulosa layer. Levels of BDNF mRNA in the thecal layer and of trkB mRNA within the granulosa cell layer increase coincident with entrance of the follicle into the preovulatory hierarchy. Localization of the BDNF mRNA transcript correlates with expression of BDNF protein within the theca interna of preovulatory follicles, while localization of trkB mRNA and protein occurs extensively within the granulosa cell layer of preovulatory follicles. This pattern of expression suggests a paracrine relationship between theca and granulosa cells for BDNF signaling via TrkB. Vasoactive intestinal peptide and gonadotropin treatments stimulate increases in levels of trkB mRNA within cultured granulosa cells derived from both prehierarchal and preovulatory follicles, and this response is increased by co-treatment with 3-isobutyl-1-methylxanthine. Finally, BDNF treatment of cultured granulosa cells from preovulatory follicles results in a modest, but significant, reduction in basal progesterone production, whereas this effect was reversed by k252a, an inhibitor of Trk kinase activity. These results support the proposals that BDNF functions as a paracrine signal in hen granulosa cells and that its physiological functions may include the modulation of steroidogenesis.

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Stable RK2-Derived Cloning Vectors for the Analysis of Gene Expression and Gene Function in Gram-Negative Bacteria

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2001.14.3.426 ◽

2001 ◽

Vol 14 (3) ◽

pp. 426-430 ◽

Cited By ~ 92

Author(s):

Bruno Dombrecht ◽

Jos Vanderleyden ◽

Jan Michiels

Keyword(s):

Gene Expression ◽

Gene Function ◽

Plasmid Stability ◽

Gram Negative Bacteria ◽

Cloning Vectors ◽

Gram Negative ◽

Gusa Gene ◽

Vector Sequences ◽

And Function ◽

Multiple Cloning Sites

The construction of several stable RK2-derived cloning vectors for the analysis of gene expression and function in gram-negative bacteria is reported. Plasmid stability is conferred by the RK2 par locus or by insertion of the spsAB or spsCD symbiotic plasmid stability loci from pNGR234a of Rhizobium sp. NGR234. The vectors carry multiple cloning sites with protection against read-through transcriptional activity of vector sequences. Vector derivatives with the constitutive nptII promoter or a promoter-less gusA gene are suitable for the study of gene function or regulation in bacteria.

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Expression of cell adhesion molecule E-cadherin in Xenopus embryos begins at gastrulation and predominates in the ectoderm.

The Journal of Cell Biology ◽

10.1083/jcb.108.6.2449 ◽

1989 ◽

Vol 108 (6) ◽

pp. 2449-2458 ◽

Cited By ~ 66

Author(s):

Y S Choi ◽

B Gumbiner

Keyword(s):

Cell Adhesion ◽

Epithelial Cell ◽

Xenopus Laevis ◽

Adhesion Molecule ◽

Cell Adhesion Molecule ◽

Cell Layer ◽

Outer Cell ◽

A6 Cells ◽

Xenopus Embryos ◽

E Cadherin

The expression of the Ca2+-dependent epithelial cell adhesion molecule E-cadherin (also known as uvomorulin and L-CAM) in the early stages of embryonic development of Xenopus laevis was examined. E-Cadherin was identified in the Xenopus A6 epithelial cell line by antibody cross-reactivity and several biochemical characteristics. Four independent mAbs were generated against purified Xenopus E-cadherin. All four mAbs recognized the same polypeptides in A6 cells, adult epithelial tissues, and embryos. These mAbs inhibited the formation of cell contacts between A6 cells and stained the basolateral plasma membranes of A6 cells, hepatocytes, and alveolar epithelial cells. The time of E-cadherin expression in early Xenopus embryos was determined by immunoblotting. Unlike its expression in early mouse embryos, E-cadherin was not present in the eggs or early blastula of Xenopus laevis. These findings indicate that a different Ca2+-dependent cell adhesion molecule, perhaps another member of the cadherin gene family, is responsible for the Ca2+-dependent adhesion between cleavage stage Xenopus blastomeres. Detectable accumulation of E-cadherin started just before gastrulation at stage 9 1/2 and increased rapidly up to the end of gastrulation at stage 15. In stage 15 embryos, specific immunofluorescence staining of E-cadherin was discernible only in ectoderm, but not in mesoderm and endoderm. The ectoderm at this stage consists of two cell layers. The outer cell layer of ectoderm was stained intensely, and staining was localized to the basolateral plasma membrane of these cells. Lower levels of staining were observed in the inner cell layer of ectoderm. The coincidence of E-cadherin expression with the process of gastrulation and its restriction to the ectoderm indicate that it may play a role in the morphogenetic movements of gastrulation and resulting segregation of embryonic germ layers.

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Dynamics and function of CXCR4 in formation of the granule cell layer during hippocampal development

Scientific Reports ◽

10.1038/s41598-017-05738-7 ◽

2017 ◽

Vol 7 (1) ◽

Cited By ~ 3

Author(s):

Yuka Mimura-Yamamoto ◽

Hiroshi Shinohara ◽

Taichi Kashiwagi ◽

Toru Sato ◽

Seiji Shioda ◽

...

Keyword(s):

Granule Cell ◽

Cell Layer ◽

Granule Cell Layer ◽

Hippocampal Development ◽

Dynamics And Function ◽

And Function

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The multiple functions of the proepicardial/epicardial cell lineage in heart development

10.1093/med/9780198757269.003.0020 ◽

2018 ◽

Author(s):

Robert Dettman ◽

Juan Antonio Guadix ◽

Elena Cano ◽

Rita Carmona ◽

Ramón Muñoz-Chápuli

Keyword(s):

Heart Development ◽

Epithelial Mesenchymal Transition ◽

Cardiac Development ◽

Cell Layer ◽

Cell Lineage ◽

Outer Cell ◽

Mesenchymal Transition ◽

Myocardial Development ◽

Epicardial Cell ◽

Outer Cell Layer

The epicardium is the outer cell layer of the vertebrate heart. In recent years, both the embryonic and adult epicardium have revealed unsuspected peculiarities and functions, which are essential for cardiac development. In this chapter we review the current literature on the epicardium, and describe its evolutionary origin, the mechanisms leading to the induction of its extracardiac progenitor tissue, the proepicardium, and the way in which the proepicardium is transferred to the heart to form the epicardium. We also describe the epicardial epithelial–mesenchymal transition from which mesenchymal cells originate, and the developmental fate of these cells, which contribute to the vascular, interstitial, valvular, and adipose tissue. Finally, we review the molecular interactions established between the epicardium and the myocardium, which are key for myocardial development and can also play a role in cardiac homeostasis. This chapter highlights how the epicardium has become a major protagonist in cardiac biology.

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