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A staging system for correct phenotype interpretation of mouse embryos harvested on embryonic day 14 (E14.5)

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ABSTRACT

We present a simple and quick system for accurately scoring the developmental progress of mouse embryos harvested on embryonic day 14 (E14.5). Based solely on the external appearance of the maturing forelimb, we provide a convenient way to distinguish six developmental sub‐stages. Using a variety of objective morphometric data obtained from the commonly used C57BL/6N mouse strain, we show that these stages correlate precisely with the growth of the entire embryo and its organs. Applying the new staging system to phenotype analyses of E14.5 embryos of 58 embryonic lethal mutant lines from the DMDD research programme (https://dmdd.org.uk) and its pilot, we show that homozygous mutant embryos are frequently delayed in development. To demonstrate the importance of our staging system for correct phenotype interpretation, we describe stage‐specific changes of the palate, heart and gut, and provide examples in which correct diagnosis of malformations relies on correct staging.

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Developmental progress of E14.5 embryos. (A–C) Theiler stages (TS) of control embryos range from TS21 (A) to TS23 (B). (D–F) TS of mutants range from TS18 to TS23 (E). Note that panel D shows a TS19 mutant. (G–I) TS21 mutant in which autolysis has started. Scoring of the major organs and detection of malformations such as double outlet right ventricle (I) is possible. (A,B,D,E,G) Volume‐rendered 3D models. (H) Volume‐rendered model sectioned in the median sagittal plane. (I) Axial HREM section. Scale bars: 1 mm.
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joa12590-fig-0001: Developmental progress of E14.5 embryos. (A–C) Theiler stages (TS) of control embryos range from TS21 (A) to TS23 (B). (D–F) TS of mutants range from TS18 to TS23 (E). Note that panel D shows a TS19 mutant. (G–I) TS21 mutant in which autolysis has started. Scoring of the major organs and detection of malformations such as double outlet right ventricle (I) is possible. (A,B,D,E,G) Volume‐rendered 3D models. (H) Volume‐rendered model sectioned in the median sagittal plane. (I) Axial HREM section. Scale bars: 1 mm.

Mentions: The developmental progress of the DMDD embryos harvested at E14.5 varied considerably, whether wildtype or mutant, irrespective of whether embryos were littermates. Profound differences were evident in surface morphology between the youngest and oldest control as well as knock‐out embryos (Fig. 1A,B,D,E). One of the lines produced only mutants that were already dead during harvesting and the tissues had started to be become autolytic (Fig. 1G–I). Despite this, comprehensive scoring of most of the features, including almost all components of the cardiovascular system in such embryos, was still feasible. In another five lines, mutants proved to be a mixture of autolytic and still alive at the time of harvest.


A staging system for correct phenotype interpretation of mouse embryos harvested on embryonic day 14 (E14.5)
Developmental progress of E14.5 embryos. (A–C) Theiler stages (TS) of control embryos range from TS21 (A) to TS23 (B). (D–F) TS of mutants range from TS18 to TS23 (E). Note that panel D shows a TS19 mutant. (G–I) TS21 mutant in which autolysis has started. Scoring of the major organs and detection of malformations such as double outlet right ventricle (I) is possible. (A,B,D,E,G) Volume‐rendered 3D models. (H) Volume‐rendered model sectioned in the median sagittal plane. (I) Axial HREM section. Scale bars: 1 mm.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5382591&req=5

joa12590-fig-0001: Developmental progress of E14.5 embryos. (A–C) Theiler stages (TS) of control embryos range from TS21 (A) to TS23 (B). (D–F) TS of mutants range from TS18 to TS23 (E). Note that panel D shows a TS19 mutant. (G–I) TS21 mutant in which autolysis has started. Scoring of the major organs and detection of malformations such as double outlet right ventricle (I) is possible. (A,B,D,E,G) Volume‐rendered 3D models. (H) Volume‐rendered model sectioned in the median sagittal plane. (I) Axial HREM section. Scale bars: 1 mm.
Mentions: The developmental progress of the DMDD embryos harvested at E14.5 varied considerably, whether wildtype or mutant, irrespective of whether embryos were littermates. Profound differences were evident in surface morphology between the youngest and oldest control as well as knock‐out embryos (Fig. 1A,B,D,E). One of the lines produced only mutants that were already dead during harvesting and the tissues had started to be become autolytic (Fig. 1G–I). Despite this, comprehensive scoring of most of the features, including almost all components of the cardiovascular system in such embryos, was still feasible. In another five lines, mutants proved to be a mixture of autolytic and still alive at the time of harvest.

View Article: PubMed Central - PubMed

ABSTRACT

We present a simple and quick system for accurately scoring the developmental progress of mouse embryos harvested on embryonic day 14 (E14.5). Based solely on the external appearance of the maturing forelimb, we provide a convenient way to distinguish six developmental sub‐stages. Using a variety of objective morphometric data obtained from the commonly used C57BL/6N mouse strain, we show that these stages correlate precisely with the growth of the entire embryo and its organs. Applying the new staging system to phenotype analyses of E14.5 embryos of 58 embryonic lethal mutant lines from the DMDD research programme (https://dmdd.org.uk) and its pilot, we show that homozygous mutant embryos are frequently delayed in development. To demonstrate the importance of our staging system for correct phenotype interpretation, we describe stage‐specific changes of the palate, heart and gut, and provide examples in which correct diagnosis of malformations relies on correct staging.

No MeSH data available.


Related in: MedlinePlus