scholarly journals Germ plasm anchors at tight junctions in the early zebrafish embryo

2021 ◽  
Author(s):  
Nadia Rostam ◽  
Alexander Goloborodko ◽  
Stephan Riemer ◽  
Andres Hertel ◽  
Sabine Klein ◽  
...  
Keyword(s):  
Zebrafish Embryo ◽  
Germ Plasm ◽  
Early Cleavage ◽  
Cell Fates ◽  
Cell Specification ◽  
Germ Cell Specification ◽  
Muscle Myosin ◽  
First Time ◽  
Bucky Ball

AbstractThe zebrafish germline is specified during early embryogenesis by inherited maternal RNAs and proteins collectively called germ plasm. Only the cells containing germ plasm will become part of the germline, whereas other cells will commit to somatic cell fates. Therefore, proper localization of germ plasm is key for germ cell specification and its removal is critical for the development of soma. The molecular mechanism underlying this process in vertebrates is largely unknown. Here we show that germ plasm localization in zebrafish is similar toXenopusand amniotes but distinct fromDrosophila. We identified non muscle myosin II (NMII) and tight junction (TJ) components as interaction candidates of Bucky ball (Buc), which is the germ plasm organizer in zebrafish. Remarkably, we also found that TJ protein ZO1 colocalizes with germ plasm and electron microscopy (EM) of zebrafish embryos uncovered TJ like structures at early cleavage furrows. In addition, injection of the TJ-receptor Claudin-d (Cldn-d) produced extra germ plasm aggregates. Our findings discover for the first time a role of TJs in germ plasm localization.

scholarly journals Tdrd6a regulates the aggregation of Buc into functional subcellular compartments that drive germ cell specification

2018 ◽  
Author(s):  
Elke F. Roovers ◽  
Lucas J.T. Kaaij ◽  
Stefan Redl ◽  
Alfred W. Bronkhorst ◽  
Kay Wiebrands ◽  
...  
Keyword(s):  
Germ Cell ◽  
Germ Plasm ◽  
Regulatory Interaction ◽  
Cell Specification ◽  
Large Aggregate ◽  
Germ Cell Specification ◽  
Tudor Domain ◽  
Specific Mrnas ◽  
Subcellular Compartmentalization ◽  
Bucky Ball

SummaryIn recent years, it has become clear that phase separation represents an important class of subcellular compartmentalization. However, relatively little is known about how the formation or disassembly of such compartments is regulated. In zebrafish, the Balbiani body (Bb) and the germ plasm (Gp) are phase-separated structures essential for germ cell specification and home to many germ cell-specific mRNAs and proteins. Throughout development, these structures range from a single large aggregate (Bb), to a dispersed state and back to relatively large assemblies (Gp). Formation of the Bb requires Bucky ball (Buc), a protein with prion-like properties. We found that the multi-tudor domain-containing protein Tdrd6a interacts directly with Buc, affecting its mobility and aggregation properties. Importantly, lack of this regulatory interaction leads to significant defects in germ cell development. Our work presents a new mechanism for how prion-like protein-aggregations can be regulated and highlights the biological relevance of such regulatory events.

Essential role of Bmp7 (snailhouse) and its prodomain in dorsoventral patterning of the zebrafish embryo

Development ◽  
2000 ◽  
Vol 127 (2) ◽  
pp. 343-354 ◽  
Author(s):  
A. Dick ◽  
M. Hild ◽  
H. Bauer ◽  
Y. Imai ◽  
H. Maifeld ◽  
...  
Keyword(s):  
Bone Morphogenetic Proteins ◽  
Double Mutant ◽  
Essential Role ◽  
Zebrafish Embryo ◽  
Temperature Sensitive ◽  
Dorsoventral Patterning ◽  
Cell Fates ◽  
Higher Temperature ◽  
Reduced Activity

Bone morphogenetic proteins (Bmps) are signaling molecules that have been implicated in a variety of inductive processes. We report here that zebrafish Bmp7 is disrupted in snailhouse (snh) mutants. The allele snh(st1) is a translocation deleting the bmp7 gene, while snh(ty68) displays a Val->Gly exhange in a conserved motif of the Bmp7 prodomain. The snh(ty68) mutation is temperature-sensitive, leading to severalfold reduced activity of mutant Bmp7 at 28 degrees C and non-detectable activity at 33 degrees C. This prodomain lesion affects secretion and/or stability of secreted mature Bmp7 after processing has occurred. Both snh(st1) and snh(ty68) mutant zebrafish embryos are strongly dorsalized, indicating that bmp7 is required for the specification of ventral cell fates during early dorsoventral patterning. At higher temperature, the phenotype of snh(ty68) mutant embryos is identical to that caused by the amorphic bmp2b mutation swirl swr(ta72) and similar to that caused by the smad5 mutation somitabun sbn(dtc24). mRNA injection studies and double mutant analyses indicate that Bmp2b and Bmp7 closely cooperate and that Bmp2b/Bmp7 signaling is transduced by Smad5 and antagonized by Chordino.

scholarly journals UNC-45A Weakens and Breaks MT Lattice Independent of its Effect on Non-Muscle Myosin II

2020 ◽  
Author(s):  
Juri Habicht ◽  
Ashley Mooneyham ◽  
Asumi Hoshino ◽  
Mihir Shetty ◽  
Xiaonan Zhang ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Myosin Ii ◽  
Human Diseases ◽  
Therapeutic Implications ◽  
Associated Functions ◽  
Muscle Myosin ◽  
First Time ◽  
In Cells

AbstractIn invertebrates, UNC-45 regulates myosin stability and functions. Vertebrates have two distinct isoforms of the protein: UNC-45B, expressed in muscle cells only and UNC-45A, expressed in all cells and implicated in regulating both Non-Muscle Myosin II (NMII)- and microtubule (MT)-associated functions. Here we show for the first time that: a) in vitro UNC-45A binds to the MT lattice and weakens its integrity leading to MT bending, breakage and depolymerization, b) in cells, UNC-45A overexpression causes loss of MT mass and increase in MT breakages, c) both in vitro and in cells, UNC-45A destabilizes MTs independent of its NMII C-terminal binding domain and destabilization occurs even in presence of the NMII inhibitor blebbistatin. These findings are consistent with a not mutually exclusive but rather dual role of UNC-45A in regulating NMII activity and MT stability.Because many human diseases, from cancer to neurodegenerative diseases, are caused by or associated with deregulation of MT stability our findings have profound implications in both, the biology of MTs as well as the biology of human diseases and possible therapeutic implications for their treatment.

scholarly journals Specification of germ cell fate in mice

2003 ◽  
Vol 358 (1436) ◽  
pp. 1363-1370 ◽  
Author(s):  
Mitinori Saitou ◽  
Bernhard Payer ◽  
Ulrike C. Lange ◽  
Sylvia Erhardt ◽  
Sheila C. Barton ◽  
...  
Keyword(s):  
Germ Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Transcriptional Repression ◽  
Single Cell Analysis ◽  
Primordial Germ Cells ◽  
Cell Specification ◽  
Signalling Molecules ◽  
Germ Cell Specification

An early fundamental event during development is the segregation of germ cells from somatic cells. In many organisms, this is accomplished by the inheritance of preformed germ plasm, which apparently imposes transcriptional repression to prevent somatic cell fate. However, in mammals, pluripotent epiblast cells acquire germ cell fate in response to signalling molecules. We have used single cell analysis to study how epiblast cells acquire germ cell competence and undergo specification. Germ cell competent cells express Fragilis and initially progress towards a somatic mesodermal fate. However, a subset of these cells, the future primordial germ cells (PGCs), then shows rapid upregulation of Fragilis with concomitant transcriptional repression of a number of genes, including Hox and Smad genes. This repression may be a key event associated with germ cell specification. Furthermore, PGCs express Stella and other genes, such as Oct – 4 that are associated with pluripotency. While these molecules are also detected in mature oocytes as maternally inherited factors, their early role is to regulate development and maintain pluripotency, and they do not serve the role of classical germline determinants.

scholarly journals Germ Cell Specification Requires Zygotic Mechanisms Rather Than Germ Plasm in a Basally Branching Insect

2013 ◽  
Vol 23 (10) ◽  
pp. 835-842 ◽  
Author(s):  
Ben Ewen-Campen ◽  
Seth Donoughe ◽  
Donald Nat Clarke ◽  
Cassandra G. Extavour
Keyword(s):  
Germ Cell ◽  
Germ Plasm ◽  
Cell Specification ◽  
Germ Cell Specification
Sign in / Sign up

Export Citation Format

Share Document