Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Induction of a second neural axis by the mouse node

R S Beddington1

  • 1National Institute for Medical Research, Ridgeway, Mill Hill, London, UK.

Development (Cambridge, England)
|March 1, 1994
PubMed
Summary
This summary is machine-generated.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Molecular effects of novel mutations in Hesx1/HESX1 associated with human pituitary disorders.

Development (Cambridge, England)·2001
Same author

The molecular phenotype of heparan sulfate in the Hs2st-/- mutant mouse.

The Journal of biological chemistry·2001
Same author

Nodal signalling in the epiblast patterns the early mouse embryo.

Nature·2001
Same author

Distinct enhancer elements control Hex expression during gastrulation and early organogenesis.

Developmental biology·2001
Same author

Getting your head around Hex and Hesx1: forebrain formation in mouse.

The International journal of developmental biology·2001
Same author

Heterozygous HESX1 mutations associated with isolated congenital pituitary hypoplasia and septo-optic dysplasia.

Human molecular genetics·2001

This study demonstrates that the mouse node, a specialized region in the early embryo, acts as an organizer capable of inducing a secondary nervous system and body segments when transplanted into a host embryo.

Area of Science:

  • Developmental biology research involving mouse node signaling
  • Embryology and pattern formation in mammalian models

Background:

No prior work had resolved whether the mouse node functions as an organizer during early development. Researchers previously identified similarities between the mouse primitive streak and organizers in other vertebrate species. That uncertainty drove investigations into whether the mouse embryo could support a secondary body axis. Scientists lacked direct evidence for this organizational capacity in mammalian models. Prior research has shown that the mouse embryonic egg cylinder is exceptionally small. This gap motivated studies to test the limits of embryonic plasticity. The current investigation addresses whether the mouse node can direct tissue patterning. Understanding these mechanisms clarifies how early mammalian body plans are established.

Purpose Of The Study:

The study aims to determine if the mouse node possesses organizer activity during early gastrulation. Researchers sought to resolve whether this small structure could induce a secondary body axis. The investigation addresses the lack of direct evidence for node-mediated patterning in mammals. Scientists wanted to compare the mouse node to established organizers in other vertebrates. This work tests the developmental potential of the mouse primitive streak. The authors hypothesized that the node could act as a source for axial mesoderm. They intended to map the fate of grafted cells within the host environment. This research clarifies the role of the node in mammalian body plan formation.

Keywords:
gastrulationprimitive streakaxial mesodermectopic somites

Frequently Asked Questions

The researchers propose that grafting a mid-gastrulation node into a posterolateral site triggers a secondary neural axis. This process involves the formation of ectopic somites, where the donor tissue exclusively generates the notochord while host cells form the neural and somitic structures.

The study utilized DiI, a lipophilic fluorescent dye, to track cell lineage. This labeling technique allowed investigators to distinguish donor-derived tissues from host-derived tissues throughout the development of the secondary axis.

A mid-gastrulation stage is necessary because the node must possess the developmental competence to organize surrounding tissues. The authors suggest that earlier or later stages might lack the specific signaling repertoire required for successful induction.

Related Experiment Videos

Main Methods:

Review approach involved microsurgical transplantation of labeled tissues into host embryos. Investigators utilized mid-gastrulation stage specimens for all grafting procedures. Researchers applied DiI to the outer surface of the donor node. Transgenic markers provided a secondary method for tracking cellular contributions. The team performed grafts at posterolateral locations within the host egg cylinder. Scientists monitored the subsequent formation of secondary axes and ectopic structures. This experimental design allowed for the precise identification of donor versus host tissue origins. Systematic observation confirmed the developmental fate of the transplanted cells.

Main Results:

Key findings from the literature reveal that node transplantation consistently induces a second neural axis. The ectopic notochord originates entirely from the donor node tissue. Host embryos provide the majority of the neurectoderm and somitic structures. Labeled cells remain detectable throughout the entire length of the notochord. The rostral boundary of the notochord shows consistent donor-derived labeling. The node maintains its labeled status throughout the observation period. These results demonstrate the organizer capacity of the mouse node. The formation of ectopic somites confirms the successful induction of a secondary body plan.

Conclusions:

The authors propose that the mouse node functions as a potent organizer during gastrulation. Synthesis and implications suggest that this region directs the formation of secondary neural structures. Evidence indicates that the node serves as a source for axial mesoderm. The donor tissue contributes exclusively to the ectopic notochord. Host cells primarily generate the surrounding neurectoderm and somites. These findings support the role of the node as a stem cell reservoir. The continuous labeling of the notochord confirms the sustained activity of these cells. This work establishes the mouse node as a key regulator of embryonic patterning.

The researchers employed transgenic marking alongside DiI labeling to verify the origin of ectopic tissues. This dual approach confirmed that the notochord originated from the donor node, whereas surrounding structures were host-derived.

The authors measured the spatial distribution of labeled cells from the cranial region to the caudal extreme. They observed that the node remained continuously labeled, indicating its role as a persistent source of notochordal cells.

The authors propose that the node acts as a stem cell source for axial mesoderm. This implies that the node maintains a population of progenitor cells that continuously contribute to the developing notochord.