Biomaterial Database

Ectoderm-mesenchyme and mesenchyme-mesenchyme interactions regulate Msx-1 expression and cellular differentiation in the murine limb bud. 1995

Y Wang, and D Sassoon

Department of Biochemistry, Boston University School of Medicine, Massachusetts 02118, USA.

The apical ectodermal ridge (AER) is a specialized thickening of the distal limb mesenchyme that has been demonstrated to support limb outgrowth and proper limb development. The homeobox gene, Msx-1, is associated with the distal limb mesenchyme (progress zone) and its expression depends upon the presence of the AER in chick limbs. We demonstrate here that the expression of Msx-1 is dependent upon the limb ectoderm in the mouse, but that the inductive capacity of murine limb ectoderm is not restricted to the AER. Msx-1 can also be maintained in limb mesenchyme by the substitution of FGF 4 for the ectoderm; however, we see that local cell-cell interactions are required for high levels of expression. Disruption of cell-cell interactions in the limb mesenchyme results in a dramatic decrease in Msx-1 levels and a precocious expression of MyoD1, suggesting that the limb environment represses differentiation and promotes cell proliferation during early development. BMP 4 and FGF 2 can also maintain Msx-1 expression in limb mesenchyme as well as retinoic acid which is usually associated with polarizing activity in the early limb. Msx-2 expression does not appear to be dependent upon cell-cell interactions as measured in these experiments. Taken together, our data suggest that the expression of Msx-1, but not Msx-2, not only requires factors from the limb ectoderm, but also relies upon cues from local cell interactions and that the spatial distribution of inductive capacities in limb ectoderm differs between the avian and murine systems.

UI	MeSH Term	Description	Entries
D008648	Mesoderm	The middle germ layer of an embryo derived from three paired mesenchymal aggregates along the neural tube.	Mesenchyme,Dorsal Mesoderm,Intermediate Mesoderm,Lateral Plate Mesoderm,Mesenchyma,Paraxial Mesoderm,Dorsal Mesoderms,Intermediate Mesoderms,Lateral Plate Mesoderms,Mesenchymas,Mesoderm, Dorsal,Mesoderm, Intermediate,Mesoderm, Lateral Plate,Mesoderm, Paraxial,Mesoderms, Dorsal,Mesoderms, Intermediate,Mesoderms, Lateral Plate,Mesoderms, Paraxial,Paraxial Mesoderms,Plate Mesoderm, Lateral,Plate Mesoderms, Lateral
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D002450	Cell Communication	Any of several ways in which living cells of an organism communicate with one another, whether by direct contact between cells or by means of chemical signals carried by neurotransmitter substances, hormones, and cyclic AMP.	Cell Interaction,Cell-to-Cell Interaction,Cell Communications,Cell Interactions,Cell to Cell Interaction,Cell-to-Cell Interactions,Communication, Cell,Communications, Cell,Interaction, Cell,Interaction, Cell-to-Cell,Interactions, Cell,Interactions, Cell-to-Cell
D002454	Cell Differentiation	Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.	Differentiation, Cell,Cell Differentiations,Differentiations, Cell
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D004475	Ectoderm	The outer of the three germ layers of an embryo.	Apical Ectodermal Ridge,Apical Ectodermal Ridges,Ectodermal Ridge, Apical,Ectoderms
D005121	Extremities	The farthest or outermost projections of the body, such as the HAND and FOOT.	Limbs,Extremity,Limb
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA
D012313	RNA	A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)	RNA, Non-Polyadenylated,Ribonucleic Acid,Gene Products, RNA,Non-Polyadenylated RNA,Acid, Ribonucleic,Non Polyadenylated RNA,RNA Gene Products,RNA, Non Polyadenylated