scholarly journals Size-reduced embryos reveal a gradient scaling-based mechanism for zebrafish somite formation

Development ◽  
2018 ◽  
Vol 145 (11) ◽  
pp. dev161257 ◽  
Author(s):  
Kana Ishimatsu ◽  
Tom W. Hiscock ◽  
Zach M. Collins ◽  
Dini Wahyu Kartika Sari ◽  
Kenny Lischer ◽  
...  
Keyword(s):  
Somite Formation ◽  
Gradient Scaling

scholarly journals Size-reduced embryos reveal a gradient scaling based mechanism for zebrafish somite formation

2017 ◽  
Author(s):  
Kana Ishimatsu ◽  
Tom W. Hiscock ◽  
Zach M. Collins ◽  
Dini Wahyu Kartika Sari ◽  
Kenny Lischer ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Expression Patterns ◽  
Size Control ◽  
Presomitic Mesoderm ◽  
Clock Period ◽  
Clock Gene Expression ◽  
Somite Formation ◽  
Axis Elongation ◽  
Summary Statement ◽  
Gradient Scaling

AbstractLittle is known about how the sizes of animal tissues are controlled. A prominent example is somite size which varies widely both within an individual and across species. Despite intense study of the segmentation clock governing the timing of somite generation, how it relates to somite size is poorly understood. Here we examine somite scaling and find that somite size at specification scales with the length of the presomitic mesoderm (PSM) despite considerable variation in PSM length across developmental stages and in surgically size-reduced embryos. Measurement of clock period, axis elongation speed, and clock gene expression patterns demonstrate that existing models fail to explain scaling. We posit a “clock and scaled gradient” model, in which somite boundaries are set by a dynamically scaling signaling gradient across the PSM. Our model not only explains existing data, but also makes a unique prediction that we experimentally confirm—the formation of periodic “echoes” in somite size following perturbation of the size of one somite. Our findings demonstrate that gradient scaling plays a central role both in progression and size control of somitogenesis.Summary statementBy comparing patterning in zebrafish embryos of different size we show that a dynamically scaling gradient in the presomitic mesoderm regulates somite size control.

A Clock and Trail Model for Somite Formation, Specialization and Polarization

2000 ◽  
Vol 205 (3) ◽  
pp. 505-510 ◽  
Author(s):  
MICHEL KERSZBERG ◽  
LEWIS WOLPERT
Keyword(s):  
Somite Formation

scholarly journals Cellular aspects of somite formation in vertebrates

2021 ◽  
pp. 203732
Author(s):  
Agnieszka M. Piatkowska ◽  
Susan E. Evans ◽  
Claudio D. Stern
Keyword(s):  
Somite Formation

her1, a zebrafish pair-rule like gene, acts downstream of notch signalling to control somite development

Development ◽  
1999 ◽  
Vol 126 (13) ◽  
pp. 3005-3014 ◽  
Author(s):  
C. Takke ◽  
J.A. Campos-Ortega
Keyword(s):  
Active Form ◽  
Notch Signalling ◽  
Paraxial Mesoderm ◽  
Presomitic Mesoderm ◽  
Essentially Normal ◽  
Early Embryos ◽  
Somite Formation ◽  
Genes Encoding ◽  
Ectopic Activation ◽  
Pair Rule

During vertebrate embryonic development, the paraxial mesoderm becomes subdivided into metameric units known as somites. In the zebrafish embryo, genes encoding homologues of the proteins of the Drosophila Notch signalling pathway are expressed in the presomitic mesoderm and expression is maintained in a segmental pattern during somitogenesis. This expression pattern suggests a role for these genes during somite development. We misexpressed various zebrafish genes of this group by injecting mRNA into early embryos. RNA encoding a constitutively active form of notch1a (notch1a-intra) and a truncated variant of deltaD [deltaD(Pst)], as well as transcripts of deltaC and deltaD, the hairy-E(spl) homologues her1 and her4, and groucho2 were tested for their effects on somite formation, myogenesis and on the pattern of transcription of putative downstream genes. In embryos injected with any of these RNAs, with the exception of groucho2 RNA, the paraxial mesoderm differentiated normally into somitic tissue, but failed to segment correctly. Activation of notch results in ectopic activation of her1 and her4. This misregulation of the expression of her genes might be causally related to the observed mesodermal defects, as her1 and her4 mRNA injections led to effects similar to those seen with notch1a-intra. deltaC and deltaD seem to function after subdivision of the presomitic mesoderm, since the her gene transcription pattern in the presomitic mesoderm remains essentially normal after misexpression of delta genes. Whereas notch signalling alone apparently does not affect myogenesis, zebrafish groucho2 is involved in differentiation of mesodermal derivatives.

scholarly journals Stochastic delay models for molecular clocks and somite formation

2007 ◽  
Author(s):  
Kevin Burrage ◽  
Pamela Burrage ◽  
André Leier ◽  
Tatiana T. Marquez-Lago
Keyword(s):  
Molecular Clocks ◽  
Stochastic Delay ◽  
Delay Models ◽  
Somite Formation

scholarly journals Analysis of chick somite myogenesis by in situ confocal microscopy of desmin expression.

1994 ◽  
Vol 42 (2) ◽  
pp. 265-272 ◽  
Author(s):  
W H Borman ◽  
D E Yorde
Keyword(s):  
Confocal Microscopy ◽  
Intermediate Filament ◽  
Intermediate Filament Protein ◽  
Chick Embryos ◽  
Whole Mount ◽  
Somite Formation ◽  
Filament Protein ◽  
The Relationship

We explored the relationship in chick embryos between somitogenesis and the onset of somite myogenesis by immunodetection of the muscle-specific intermediate filament protein desmin. Early somite desmin expression was detected by whole-mount in situ confocal microscopy. No detectable somite desmin was observed in embryos of 15 somites (Stage 12) or younger. In embryos having between 16 and 26 somites (Stages 12-15), desmin could be detected in somites positioned increasingly more caudal in the embryo. Finally, in embryos of 27 somites (Stage 16) and older, somite desmin expression was consistently present in all but the caudal-most six somites. Although the rate of somite formation is fairly constant, the rate of observed somite desmin expression progressing caudally in the embryo is greater initially than the rate of segmentation. After an embryo has formed about 27 somites, the rate of desmin appearance parallels the rate of segmentation at a distance of about six somites. This result suggests that very early somite myogenesis is not linked to somitogenesis.

scholarly journals Reaction-Diffusion Approach to Somite Formation

2015 ◽  
Vol 48 (1) ◽  
pp. 346-351
Author(s):  
Annie Lemarchand ◽  
Carlo Bianca
Keyword(s):  
Reaction Diffusion ◽  
Somite Formation

Protein Accumulation in Early Chick Embryos Grown under Different Conditions of Explantation

Development ◽  
1959 ◽  
Vol 7 (1) ◽  
pp. 66-72
Author(s):  
L. Gwen Britt ◽  
Heinz Herrmann
Keyword(s):  
Chick Embryo ◽  
Slow Rate ◽  
The Other ◽  
Protein Accumulation ◽  
Chick Embryos ◽  
Developmental Processes ◽  
Embryonic Tissues ◽  
Somite Formation ◽  
Explanted Chick Embryo

The recent development of techniques originally devised by Waddington (1932) for the maintenance of the explanted chick embryo (Spratt, 1947; New, 1955; Wolff & Simon, 1955) has opened the possibility of determining quantitatively some parameters of the developmental processes occurring in embryonic tissues under these conditions. As a result of such measurements, protein accumulation in explanted embryos was found to be much smaller than in embryos developing in the egg. On the other hand, the progress of somite formation was found to take place at similar rates in embryos developing as explants or in situ (Herrmann & Schultz, 1958). The slow rate of protein accumulation in the explanted embryos made it seem desirable to investigate whether under some other conditions of explantation protein accumulation would approach more closely the rate of protein formation observed in the naturally developing embryo.

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