Intraspecific chick/chick chimaeras: Dystrophic somitic mesoderm transplanted to a normal host forms muscles with a dystrophic phenotype

Cauwenbergs, P.; Butler, Jane; Cosmos, Ethel

doi:10.1016/0304-3940(86)90132-1

Cited by 8 publications

(1 citation statement)

References 9 publications

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“…These results and the anatomical data discussed below strongly contrasts to the degeneration of muscle and motoneurons when thoracic motoneurons innervate limb musculature (Detwiler, 1936;Szekely and Szentagothai, 1962;Straznicky, 1963Straznicky, , 1967Szekely, 1963Szekely, , 1973Butler et al, 1986;O'Brien and Oppenheim, 1990;O'Brien, Landmesser, and Oppenheim, 1990). The finding that neuromuscular union is maintained between normal thoracic spinal nerves and transplanted dystrophic muscle Cosmos, 1986b, Butler andCosmos, 1987) implies that some muscle factor (controlled by the defective gene of the dystrophic mutant) determines recognition and hence maintenance of contact. The type of incompatibility between muscle and motoneurons evident in the thoracically innervated hindlimbs does not appear to exist in the case of hindlimb muscle and brachial motoneurons.…”

Section: The Loss Of Function In Brachially Innervated Hindlimbsmentioning

confidence: 92%

Brachially innervated ectopic hindlimbs in the chick embryo. I. Limb motility and motor system anatomy during the development of embryonic behavior

Kitchener

Laing

1993

J. Neurobiol.

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The functional status of brachially innervated hindlimbs, produced by transplanting hindlimb buds of chick embryos in place of forelimb buds, was quantified by analyzing the number and temporal distribution of spontaneous limb movements. Brachially innervated hindlimbs exhibited normal motility until E10 but thereafter became significantly less active than normal limbs and the limb movements were more randomly distributed. Contrary to the findings with axolotls and frogs, functional interaction between brachial motoneurons and hindlimb muscles cannot be sustained in the chick embryo. Dysfunction is first detectable at E10 and progresses to near total immobility by E20 and is associated with joint ankylosis and muscular atrophy. Although brachially innervated hindlimbs were virtually immobile by the time of hatching (E21), they produced strong movements in response to electrical stimulation of their spinal nerves, suggesting a central rather than peripheral defect in the motor system. The extent of motoneuron death in the brachial spinal cord was not significantly altered by the substitution of the forelimb bud with the hindlimb bud, but the timing of motoneuron loss was appropriate for the lumbar rather than brachial spinal cord, indicating that the rate of motoneuron death was dictated by the limb. Measurements of nuclear area indicated that motoneuron size was normal during the motoneuron death period (E6-E10) but the nuclei of motoneurons innervating grafted hindlimbs subsequently became significantly larger than those of normal brachial motoneurons. Although the muscle mass of the grafted hindlimb at E18 was significantly less than that of the normal hindlimb (and similar to that of a normal forelimb), electronmicroscopic examination of the grafted hindlimbs and brachial spinal cords of E20 embryos revealed normal myofiber and neuromuscular junction ultrastructure and a small increase in the number of axosomatic synapses on cross-sections of motoneurons innervating grafted hindlimbs compared to motoneurons innervating normal forelimbs. The anatomical data indicate that, rather than being associated with degenerative changes, the motor system of the brachial hindlimb of late-stage embryos is intact, but inactive.

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Section: The Loss Of Function In Brachially Innervated Hindlimbsmentioning

confidence: 92%

Brachially innervated ectopic hindlimbs in the chick embryo. I. Limb motility and motor system anatomy during the development of embryonic behavior

Kitchener

Laing

1993

J. Neurobiol.

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Role of Delta-Like-3 in Mammalian Somitogenesis and Vertebral Column Formation

Chapman

Dunwoodie

Advances in Experimental Medicine and Biology

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Specification and segmentation of the paraxial mesoderm

1994

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Somite formation in the mouse embryo begins with the recruitment of mesenchymal cells into the paraxial mesoderm. Cells destined for the paraxial mesoderm are recruited from a progenitor population found first in the embryonic ectoderm and later in the primitive streak and the tail bud. Experimental evidence suggests that the allocation of precursor cells to different mesodermal lineages may be related to the site at which the cells ingress through the primitive streak. An increasing number of genes, such as those encoding growth factor and transcription factors, are now known to be expressed in the primitive streak. It is not known whether the specification of mesodermal cell fate has any relationship with the activity of genes that are expressed in the restricted cell populations of the primitive streak. Somitomeres, which are spherical clusters of mesenchymal cells in the presomitic mesoderm, presage the segmentation of somites in the paraxial mesoderm. The somitomeric organization denotes a pre-pattern of segmentation that defines the physical boundary and the bilateral symmetry of the mesodermal segments in the body axis. The establishment of new somitomeres seems to require the interaction of a resident cell population in the presomitic mesoderm and the incoming primitive streak cells. Cell mixing, which occurs in the somitomeres prior to somite segmentation, poses problems in understanding the developmental role of the somitomere and the real significance of the partitioning of the node-derived and primitive streak-derived cells in the mesodermal segments. In the presomitic mesoderm, the expression of some genes that encode transcription factors, growth factors or tyrosine kinase receptor, and the localization of certain cell adhesion molecules are closely associated with distinct morphogenetic events, such as cell clustering in the presomitic mesoderm and the formation of epithelial somites. There is, however, very little direct relationship between the spatial pattern of gene expression and the somitomeric organization in the presomitic mesoderm. Results of somite transplantation experiments suggest that both the segmental address and the morphogenetic characteristics of the somite may be determined during somite segmentation. Regional identity of the paraxial mesodermal segment is conferred by the expression of a combination of Hox genes in the sclerotome and probably other lineage-specific genes that are subject to imprinting. Superimposed on the global metameric pattern, two orthogonal polarities of cell differentiation are endowed in each mesodermal segment. The rostro-caudal polarity is established prior to somite segmentation. This polarity is later manifested by the subdivision of the sclerotome and the alliance of the neural crest cells and motor axons with the rostral half-somite.(ABSTRACT TRUNCATED AT 400 WORDS)

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Intraspecific chick/chick chimaeras: Dystrophic somitic mesoderm transplanted to a normal host forms muscles with a dystrophic phenotype

Cited by 8 publications

References 9 publications

Brachially innervated ectopic hindlimbs in the chick embryo. I. Limb motility and motor system anatomy during the development of embryonic behavior

Brachially innervated ectopic hindlimbs in the chick embryo. I. Limb motility and motor system anatomy during the development of embryonic behavior

Role of Delta-Like-3 in Mammalian Somitogenesis and Vertebral Column Formation

Specification and segmentation of the paraxial mesoderm

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