ch 16 - Mesoderm Induction in Xenopus

A comprehensive set of flashcards focusing on the key vocabulary and concepts related to the mesoderm induction process in Xenopus, based on the lecture notes.

Organizer

A structure that inhibits signals from ventral mesoderm and specifies dorsal mesoderm.

Nieuwkoop Center

A region that specifies the dorsal-most mesoderm, acting as a Spemann organizer.

Fibroblast Growth Factor (FGF) family

A family of factors that can induce mesoderm formation.

Transforming Growth Factor ß (TGF-ß)

A family that includes Vg1, activin, and nodal-related proteins that are involved in mesoderm induction.

Mesoderm Inducer Criteria

Criteria include biological activity, correct expression pattern, responsiveness of appropriate cells, and inhibition must prevent induction.

Anti-sense oligo

A strand of RNA designed to disrupt target mRNA and inhibit gene expression.

Nodal-related proteins

Proteins that play an important role in mesoderm induction; mutations can lead to disrupted mesoderm formation.

Vg1

A TGF-ß homolog that can induce mesoderm in animal caps but has no evidence as a processed, soluble protein in vivo.

BMP-4 and Xwnt-8

Factors that ventralize and antineuralize, blocking neural induction.

Chordin and Noggin

Factors that bind to BMP and prevent its interaction with its receptors, thus promoting neural induction.

Mesoderm patterning

The process by which mesodermal tissue is organized and specified during embryonic development.

Evolutionary conservation

The preservation of biological functions or structures across species, such as BMP4 and dpp.

Functional knockouts

Organisms in which specific genes have been intentionally deactivated or 'knocked out' to study their functions.

Concentration-dependent induction

The phenomenon where the induction of mesodermal structures depends on the concentration of inducing factors like Xnr1.

Dominant negative receptor

A mutated receptor that inhibits the function of normal receptors, blocking mesoderm or axial structure development.

Zygotic gene expression

Gene expression that occurs after fertilization, which is critical for development of specific structures.

what is the criteria for bona fide mesoderm inducer

activity, expression pattern, appropriate cells can respond to inducer, requirement

Functional knockout for studying gene function

A method where specific genes are inactivated to observe effects on development or physiology.

Uses of functional knockouts

Functional knockouts are utilized in research to understand gene roles in pathways, diseases, and developmental processes.

Example of functional knockout organism

Mice genetically engineered to have certain gene knockouts to study human diseases.

Comparison with wild type

Analyzing differences between functional knockouts and wild type organisms helps elucidate the role of the knocked-out gene.

Genetic compensation

A phenomenon where other genes may upregulate to compensate for the loss of function in a knockout organism.

Candidate mesoderm inducing factors

Factors that have the potential to promote the formation of mesodermal tissue during embryonic development.

Xenopus Nodal

A member of the TGF-ß superfamily that acts as a potent mesoderm inducer in amphibians like Xenopus.

Activin

A TGF-ß family member known to have mesoderm-inducing properties, often used in cell culture studies.

Vg1

A TGF-ß homolog that has been shown to induce mesoderm in certain experimental models.

Fibroblast Growth Factors (FGFs)

A group of proteins that can induce mesoderm formation and contribute to various developmental processes.

Nodal-related proteins

Proteins that play a critical role in mesoderm induction, essential for proper embryonic development.

Bone Morphogenetic Proteins (BMPs)

A group of signaling molecules that, in certain contexts, can influence mesodermal differentiation and patterning.

Wnt proteins

Secreted molecules that can promote mesodermal induction and regulate cell fate in development.

Which three xenopus nodal-related proteins can induce mesoderm in animal caps

are Xnr1, Xnr2, and Xnr4

where does Xnr expression start

dorsal side at midblastula and expands to the rest of the endoderm

do dorsal endoderm or ventral endoderm express higher levels of Xnrs and for a longer time?

dorsal endoderm

both dorsal mesoderm and neural inducers

noggin, chordin, follistatin

dorsalizing factors of noggin, chordin and follostatin

induce dorsal mesoderm from precursor tissue of ventral mesodermand neural tissue formation from ectoderm.

neural inducers of noggin, chordin, amd follistatin

induce anterior-type neural tissue from animal cap cells when injected with mRNA and are expressed in dorsal lip