Analysis of gelsolin expression pattern in developing chicken embryo reveals high GSN expression level in tissues of neural crest origin
Antonina Joanna Mazur
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Gabriela Morosan-Puopolo
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Aleksandra Makowiecka
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Maria Malicka-Baszkiewicz
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Dorota Nowak
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Beate Brand-Saberi
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G. Morosan-Puopolo B. Brand-Saberi Department of Anatomy and Molecular Embryology, Ruhr University of Bochum
, Bochum,
Germany
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A. J. Mazur (&) A. Makowiecka M. Malicka-Baszkiewicz D. Nowak Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw
, ul. Joliot-Curie 14a, 50-383 Wrocaw,
Poland
Gelsolin is one of the most intensively studied actin-binding proteins. However, in the literature comprehensive studies of GSN expression during development have not been performed yet in all model organisms. In zebrafish, gelsolin is a dorsalizing factor that modulates bone morphogenetic proteins signaling pathways, whereas knockout of the gelsolin coding gene, GSN is not lethal in murine model. To study the role of gelsolin in development of higher vertebrates, it is crucial to estimate GSN expression pattern during development. Here, we examined GSN expression in the developing chicken embryo. We applied numerous methods to track GSN expression in developing embryos at mRNA and protein level. We noted a characteristic GSN expression pattern. Although GSN transcripts were present in several cell types starting from early developmental stages, a relatively high GSN expression was observed in eye, brain vesicles, midbrain, neural tube, heart tube, and splanchnic mesoderm. In older embryos, we observed a high GSN expression in the cranial ganglia and dorsal root ganglia. A detailed analysis of 10-day-old chicken embryos revealed high amounts of gelsolin especially within the head region: in the olfactory and optic systems, meninges, nerves, muscles, presumptive pituitary gland, and pericytes, but not oligodendrocytes in the brain. Obtained results suggest that GSN is expressed at high levels in some tissues of ectodermal origin including all neural crest derivatives. Additionally, we describe that silencing of GSN expression in brain vesicles leads to altered morphology of the mesencephalon. This implies gelsolin is crucial for chicken brain development.
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Actins, abundantly expressed in all animal cell types, are
capable of forming polymers and take part in several
cellular processes such as cell motility,
chemoattractantcontrolled (or directed) migration, trafficking of cellular
organelles and chromosomes, junction formation, mitosis,
transcription, and muscle contraction (Perrin and Ervasti
2010). Consequently, it is understandable that actin
dynamics have to be strictly controlled. There are more
than 100 Actin-binding proteins (ABPs), which regulate
actin polymerization/depolymerization and involvement in
several cellular processes (Winder and Ayscough 2005).
Although it was shown that actin is indispensable for
mammalian embryonic development (Shawlot et al. 1998),
not much is known about the role of ABPs in vertebrate
embryo development. There are, however, some
exceptions. For instance, it has been shown that thymosin beta4
plays a role in brain development of chicken embryos
(Wirsching et al. 2012) and that it is expressed in the neural
tube and brain vesicles, the heart, blood vessels, and
feathers (Dathe and Brand-Saberi 2004). The presence of
thymosin beta4 mRNA was strongly manifested in neural
tissues like the neural tube and dorsal root ganglia. These
results are similar to those obtained by researchers, who
studied thymosin beta4 expression in mouse embryos
(Gomez-Marquez et al. 1996). In contrast, another
thymosin beta family member, thymosin beta15avian is
asymmetrically expressed in Hensens node and could thus be
involved in left/right axis formation; it has been described
to have a function in myogenesis in chicken embryos
(Chankiewitz et al. 2014). Other G-actin-binding proteins
belong to the ADF/cofilin family. Actin depolymerizing
factor (ADF) seems to be dispensable during mouse
embryo development (Gurniak et al. 2005), but n-cofilin is
crucial for migration of cells derived from the paraxial
mesoderm. On the other hand, decreased expression of
non-muscle cofilin (n-cofilin) in murine preimplantation
embryos is important for compaction during blastocyst
formation (Ma et al. 2009).
Here, we focus on the gelsolin expression pattern in
developing chicken embryos. Gelsolin is coded by one
gene (GSN); however, its expression yields several protein
isoforms. In humans, the existence of three isoforms:
plasma (isoform a, 86 kDa), cytoplasmic (isoform b,
81 kDa), and brain (isoform c, 82 kDa) is well
documented. Furthermore, the presence of some other isoforms
can be predicted. Gelsolin, a Ca2?, phosphatidylinositol
4,5-biphosphate (PIP2) and pH-dependent six-domain (G1
G6) protein, severs actin filaments, caps the barbed ends of
actin filaments and under certain conditions nucleates actin
monomers (Mannherz et al. 2010; Li et al. 2012; Nag et al.
2013). However, gelsolin seems to have more functions
than severing actin filame (...truncated)