Related Experiment Video
Updated: Aug 7, 2026
08:08
Chicken Recombinant Limbs Assay to Understand Morphogenesis, Patterning, and Early Steps in Cell Differentiation
Published on: January 12, 2022
Mechanistic insight into how Shh patterns the vertebrate limb
Edwina McGlinn1, Clifford J Tabin
1Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.
Current Opinion in Genetics & Development
|June 30, 2006
Summary
Sonic hedgehog (Shh) signaling is crucial for limb development, patterning digits with unique characteristics. Recent research reveals complex mechanisms in how Shh gradients are established and received, prompting new models for embryonic patterning.
Area of Science:
- Developmental Biology
- Molecular Biology
- Genetics
Background:
- Embryonic patterning in newborn limbs is complex.
- Classical studies proposed long-range signals for cell fate determination.
- Sonic hedgehog (Shh) localized expression patterns limb structures and digits.
Purpose of the Study:
- To re-evaluate limb patterning models at a molecular level.
- To understand the complex mechanisms of Shh gradient establishment and reception.
Main Methods:
- Analysis of localized Sonic hedgehog (Shh) gene expression.
- Investigating molecular gradients in limb development.
- Re-evaluation of theoretical frameworks for cell signaling.
Main Results:
- Shh differentially patterns structures across the limb field.
- Digits develop unique characteristics due to Shh activity.
- Unexpected complexity in Shh gradient establishment and reception identified.
Conclusions:
- Current models of limb patterning require re-evaluation.
- Understanding Shh gradient dynamics is key to deciphering limb development.
- Further research is needed to fully elucidate these complex patterning mechanisms.
More Related Videos
Related Concept Videos
02:33Hedgehog Signaling Pathway
The Hedgehog gene (Hh) was first discovered due to its control of the growth of disorganized, hair-like bristles phenotype in Drosophila, much like hedgehog spines. Hh plays a crucial role in the development of organs and the maintenance of homeostasis in both invertebrates and vertebrates. However, while Drosophila has only one Hh protein, mammals have multiple functional Hedgehog proteins - Sonic (Shh), Desert (Dhh), and Indian Hedgehog (Ihh). All of these homologous proteins have adapted to...
01:09Changes in the Appendicular Skeleton with Age
The upper and lower limb initially develops as a small bulge called a limb bud, which appears on the lateral side of the early embryo. The upper limb bud appears near the end of the fourth week of development, with the lower limb bud appearing shortly after.
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
01:31Mechanism of Lamellipodia Formation
Cells migrating in response to external stimuli form lamellipodia, which are thin membrane protrusions supported by a mesh of linked, branched, or unbranched actin filaments. These actin filaments interact with myosin motor proteins, creating the dynamic actomyosin complex within the cytoskeleton. Contractility, or the ability to generate contractile stress, is inherent to the actomyosin complex. It helps cells detect the stiffness of the surrounding ECM and exert contractile force for...
01:51Determination
During embryogenesis, cells become progressively committed to different fates through a two-step process: specification followed by determination. Specification is demonstrated by removing a segment of an early embryo, “neutrally” culturing the tissue in vitro—for example, in a petri dish with simple medium—and then observing the derivatives. If the cultured region gives rise to cell types that it would normally generate in the embryo, this means that it is specified. In contrast, determination...