Observations of Dependent Histogenesis in Salamander Limb Development

Development ◽  
1963 ◽  
Vol 11 (2) ◽  
pp. 325-338
Author(s):  
Cyril V. Finnegan
Keyword(s):  
Limb Development ◽  
Cell Mass ◽  
Limb Bud ◽  
Previous Experience ◽  
Limb Buds ◽  
Self Differentiation ◽  
Positive Results

Previous work in this laboratory (Finnegan, 1962) had suggested that limb development might be specifically enhanced by experimentally associated somite mesoderm tissue. Detwiler (1938), Swett (1945) and Nicholas (1958) called attention to the influence of this mesoderm in the production of duplications when limb buds were transplanted heterotopically to the superficial somite region and, more recently, Amano (1960) stated that somite tissue was required, inductively and materially, for limb development. In an analysis of development it is assumed that a group of cells, whose histogenesis has been determined by their previous experience, will evidence that histogenesis if placed in an environment in which they continue to develop. Thus, after limb bud transplantation to the flank in urodeles, positive results (that is, histogenesis, proximally, accompanied by growth, distally) have been interpreted as self-differentiation of the limb bud cell mass (see review by Nicholas, 1955).

Role of the chicken homeobox-containing genes GHox-4.6 and GHox-8 in the specification of positional identities during the development of normal and polydactylous chick limb buds

Development ◽  
1992 ◽  
Vol 115 (2) ◽  
pp. 629-637 ◽  
Author(s):  
C.N. Coelho ◽  
W.B. Upholt ◽  
R.A. Kosher
Keyword(s):  
Limb Development ◽  
Ectopic Expression ◽  
Limb Bud ◽  
Chick Embryos ◽  
Limb Buds ◽  
Hox Gene ◽  
Wing Bud ◽  
Coated Bead ◽  
Experimentally Induced

During early stages of normal chick limb development, the homeobox-containing (HOX) gene GHox-4.6 is expressed throughout the posterior mesoderm of the wing bud from which most of the skeletal elements including the digits will develop, whereas GHox-8 is expressed in the anterior limb bud mesoderm which will not give rise to skeletal elements. In the present study, we have examined the expression of GHox-4.6 and GHox-8 in the wing buds of two polydactylous mutant chick embryos, diplopodia-5 and talpid2, from which supernumerary digits develop from anterior limb mesoderm, and have also examined the expression of these genes in response to polarizing zone grafts and retinoic acid-coated bead implants which induce the formation of supernumerary digits from anterior limb mesoderm. We have found that the formation of supernumerary digits from the anterior mesoderm in mutant and experimentally induced polydactylous limb buds is preceded by the ectopic expression of GHox-4.6 in the anterior mesoderm and the coincident suppression of GHox-8 expression in the anterior mesoderm. These observations suggest that the anterior mesoderm of the polydactylous limb buds is “posteriorized” and support the suggestion that GHox-8 and GHox-4.6, respectively, are involved in specifying the anterior non-skeletal and posterior digit-forming regions of the limb bud. Although the anterior mesodermal domain of GHox-8 expression is severely impaired in the mutant and experimentally induced polydactylous limb buds, this gene is expressed by the prolonged, thickened apical ectodermal ridges of the polydactylous limb buds that extend along the distal anterior as well as the distal posterior mesoderm.(ABSTRACT TRUNCATED AT 250 WORDS)

Sonic hedgehog is not required for polarising activity in the Doublefoot mutant mouse limb bud

Development ◽  
1998 ◽  
Vol 125 (3) ◽  
pp. 351-357 ◽  
Author(s):  
C. Hayes ◽  
J.M. Brown ◽  
M.F. Lyon ◽  
G.M. Morriss-Kay
Keyword(s):  
Gene Expression ◽  
Limb Development ◽  
Target Genes ◽  
Anterior Part ◽  
Expression Patterns ◽  
Ectopic Expression ◽  
Mutant Gene ◽  
Limb Bud ◽  
Active Constituent ◽  
Limb Buds

The mouse mutant Doublefoot (Dbf) shows preaxial polydactyly of all four limbs. We have analysed limb development in this mutant with respect to morphogenesis, gene expression patterns and ectopic polarising activity. The results reveal a gain-of-function mutation at a locus that mediates pattern formation in the developing limb. Shh expression is identical with that of wild-type embryos, i.e. there is no ectopic expression. However, mesenchyme from the anterior aspects of Dbf/+ mutant limb buds, when transplanted to the anterior side of chick wing buds, induces duplication of the distal skeletal elements. Mid-distal mesenchymal transplants from early, but not later, Dbf/+ limb buds are also able to induce duplication. This demonstration of polarising activity in the absence of Shh expression identifies the gene at the Dbf locus as a new genetic component of the Shh signalling pathway, which (at least in its mutated form) is able to activate signal transduction independently of Shh. The mutant gene product is sufficient to fulfil the signalling properties of Shh including upregulation of the direct Shh target genes Ptc and Gli, and induction of the downstream target genes Bmp2, Fgf4 and Hoxd13. The expression domains of all these genes extend from their normal posterior domains into the anterior part of the limb bud without being focused on a discrete ectopic site. These observations dissociate polarising activity from Shh gene expression in the Dbf/+ limb bud. We suggest that the product of the normal Dbf gene is a key active constituent of the polarising region, possibly acting in the extracellular compartment.

The chick limbless mutation causes abnormalities in limb bud dorsal-ventral patterning: implications for the mechanism of apical ridge formation

Development ◽  
1996 ◽  
Vol 122 (12) ◽  
pp. 3851-3861 ◽  
Author(s):  
U. Grieshammer ◽  
G. Minowada ◽  
J.M. Pisenti ◽  
U.K. Abbott ◽  
G.R. Martin
Keyword(s):  
Gene Expression ◽  
Limb Development ◽  
Positional Information ◽  
Limb Bud ◽  
Local Application ◽  
Chick Embryos ◽  
Limb Buds ◽  
Early Stages ◽  
Potential Link

In chick embryos homozygous for the limbless mutation, limb bud outgrowth is initiated, but a morphologically distinct apical ridge does not develop and limbs do not form. Here we report the results of an analysis of gene expression in limbless mutant limb buds. Fgf4, Fgf8, Bmp2 and Msx2, genes that are expressed in the apical ridge of normal limb buds, are not expressed in the mutant limb bud ectoderm, providing molecular support for the hypothesis that limb development fails in the limbless embryo because of the inability of the ectoderm to form a functional ridge. Moreover, Fgf8 expression is not detected in the ectoderm of the prospective limb territory or the early limb bud of limbless embryos. Since the early stages of limb bud outgrowth occur normally in the mutant embryos, this indicates that FGF8 is not required to promote initial limb bud outgrowth. In the absence of FGF8, Shh is also not expressed in the mutant limb buds, although its expression can be induced by application of FGF8-soaked beads. These observations support the hypothesis that Fgf8 is required for the induction of Shh expression during normal limb development. Bmp2 expression was also not detected in mutant limb mesoderm, consistent with the hypothesis that SHH induces its expression. In contrast, SHH is not required for the induction of Hoxd11 or Hoxd13 expression, since expression of both these genes was detected in the mutant limb buds. Thus, some aspects of mesoderm A-P patterning can occur in the absence of SHH and factors normally expressed in the apical ridge. Intriguingly, mutant limbs rescued by local application of FGF displayed a dorsalized feather pattern. Furthermore, the expression of Wnt7a, Lmx1 and En1, genes involved in limb D-V patterning, was found to be abnormal in mutant limb buds. These data suggest that D-V patterning and apical ridge formation are linked, since they show that the limbless mutation affects both processes. We present a model that explains the potential link between D-V positional information and apical ridge formation, and discuss the possible function of the limbless gene in terms of this model.

Apical ridge dependent and independent mesodermal domains of GHox-7 and GHox-8 expression in chick limb buds

Development ◽  
1992 ◽  
Vol 116 (3) ◽  
pp. 811-818 ◽  
Author(s):  
M.A. Ros ◽  
G. Lyons ◽  
R.A. Kosher ◽  
W.B. Upholt ◽  
C.N. Coelho ◽  
...  
Keyword(s):  
Pattern Formation ◽  
Limb Development ◽  
Apical Ectodermal Ridge ◽  
Limb Bud ◽  
Rapid Decline ◽  
Limb Buds ◽  
Limb Outgrowth ◽  
Removal Experiments ◽  
The Relationship

The homeobox-containing genes GHox-7 and GHox-8 have been proposed to play fundamental roles in limb development. The expression of GHox-8, by the apical ridge cells, and GHox-7, in the subridge mesoderm, suggests the involvement of these two genes in limb outgrowth and proximo-distal pattern formation. A straightforward way to test this is to remove the apical ridge. Here we report the relationship between the mesodermal expression of GHox-7 and GHox-8 and the apical ectodermal ridge in the chick limb bud. The data from ridge removal experiments indicate that there are at least two domains of GHox-7 expression in the apical limb bud mesoderm. The posterior subridge GHox-7 domain in the progress zone requires the influence of the apical ridge for continued expression, while the anterior GHox-7 domain continues expression after ridge removal. Posterior subridge mesoderm is exquisitely sensitive to the loss of the ridge in that GHox-7 expression by these cells is reduced in only two hours and undetectable by three hours after ridge removal. It would appear that one of the ways progress zone cells respond to the apical ridge signal is by expressing GHox-7. The loss of ridge influence whether by growth at the apex or by ridge removal is followed by an unusually rapid decline in detectable GHox-7 transcripts. Maintenance of GHox-8 expression by the anterior mesoderm appears to be independent of the presence of the apical ridge.(ABSTRACT TRUNCATED AT 250 WORDS)

Fine structural analysis of limb development in the wingless mutant chick embryo

Development ◽  
1982 ◽  
Vol 68 (1) ◽  
pp. 69-86
Author(s):  
Linwood M. Sawyer
Keyword(s):  
Gap Junctions ◽  
Basal Lamina ◽  
Limb Development ◽  
Mesenchymal Cell ◽  
Ruthenium Red ◽  
Limb Bud ◽  
Normal Embryo ◽  
Limb Buds ◽  
Transmission Electron ◽  
Dense Vesicles

The fine structure of the normal and wingless chick limb bud was examined with scanning and transmission electron microscopy. The apical ectodermal ridge (AER) of the normal limb bud was composed of pseudostratined columnar cells. These cells contained gap junctions, electron-dense vesicles, and numerous microtubules and microfilaments that were oriented perpendicularly to the basal lamina. Microfilaments were also found coursing transversely in the basal cell cytoplasm. The ectoderm of the wingless mutant limb bud lacked a well-developed AER and resembled the dorsal and ventral ectoderm of the normal embryo. Gap junctions and electron-dense vesicles found in the AER of the normal limb bud were not apparent in the mutant ectoderm. The normal-limb bud mesoderm is composed of stellate cells that are oriented at right angles to the overlying ectoderm. There is a prominent subectodermal space that is traversed by numerous mesenchymal cell filopodia. The mesodermal cells of the mutant limb bud are compact and round and have short stubby filopodia, while the cells of the adjacent flank mesoderm are stellate. The subectodermal space is absent and the mesodermal cells are in intimate association with the basal lamina of the overlying ectoderm. Ruthenium red was employed as an extracellular marker for glycosaminoglycan$. No differences were found in the distribution of these substances in normal and mutant limb buds. In severalcases the basal lamina of the mutant limb bud ectoderm was discontinuous aqd the lamina lucida wasnot apparent. The results indicate that the mutation has an effect on the limb buds' ability to maintain a well-developed AER and basal lamina. It also suggest$ that the wingless gene affects the shape and possibly the mobility of the limb-bud mesoderm cells.

Expression of chicken fibroblast growth factor homologous factor (FHF)-1 and of differentially spliced isoforms of FHF-2 during development and involvement of FHF-2 in chicken limb development

Development ◽  
1999 ◽  
Vol 126 (2) ◽  
pp. 409-421
Author(s):  
I. Munoz-Sanjuan ◽  
B.K. Simandl ◽  
J.F. Fallon ◽  
J. Nathans
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Neural Tube ◽  
Limb Development ◽  
Limb Bud ◽  
Fibroblast Growth ◽  
Limb Buds ◽  
Adjacent Structures ◽  
Morphological Defects ◽  
Zone Of Polarizing Activity

Members of the fibroblast growth factor (FGF) family have been identified as signaling molecules in a variety of developmental processes, including important roles in limb bud initiation, growth and patterning. This paper reports the cloning and characterization of the chicken orthologues of fibroblast growth factor homologous factors-1 and −2 (cFHF-1/cFGF-12 and cFHF-2/cFGF-13, respectively). We also describe the identification of a novel, conserved isoform of FHF-2 in chickens and mammals. This isoform arises by alternative splicing of the first exon of the FHF-2 gene and is predicted to encode a polypeptide with a distinct amino-terminus. Whole-mount in situ hybridization reveals restricted domains of expression of cFHF-1 and cFHF-2 in the developing neural tube, peripheral sensory ganglia and limb buds, and shows that the two cFHF-2 transcript isoforms are present in non-overlapping spatial distributions in the neural tube and adjacent structures. In the developing limbs, cFHF-1 is confined to the posterior mesoderm in an area that encompasses the zone of polarizing activity and cFHF-2 is confined to the distal anterior mesoderm in a region that largely overlaps the progress zone. Ectopic cFHF-2 expression is induced adjacent to grafts of cells expressing Sonic Hedgehog and the zone of cFHF-2 expression is expanded in talpid2 embryos. In the absence of the apical ectodermal ridge or in wingless or limbless mutant embryos, expression of cFHF-1 and cFHF-2 is lost from the limb bud. A role for cFHF-2 in the patterning and growth of skeletal elements is implied by the observation that engraftment of developing limb buds with QT6 cells expressing a cFHF-2 isoform that is normally expressed in the limb leads to a variety of morphological defects. Finally, we show that a secreted version of cFHF-2 activates the expression of HoxD13, HoxD11, Fgf-4 and BMP-2 ectopically, consistent with cFHF-2 playing a role in anterior-posterior patterning of the limb.

Experiments on developing limb buds of the axolotl Ambystoma mexicanum

Development ◽  
1980 ◽  
Vol 57 (1) ◽  
pp. 177-187
Author(s):  
M. Maden ◽  
B. C. Goodwin
Keyword(s):  
Limb Development ◽  
Ambystoma Mexicanum ◽  
Limb Bud ◽  
Limb Buds ◽  
Vertebrate Limb ◽  
Two Systems ◽  
Vertebrate Limb Development ◽  
Supernumerary Limbs

Various experiments were performed on the limb buds of axolotls to compare the behaviour of amphibian limbs with that previously reported for chick limbs. Following removalof the tip or whole limb bud, extensive powers of regulation were observed since complete limbs always formed. Similarly after distal to proximal grafts intercalary regulation occurred to produce perfect limbs and after proximal to distal grafts serial repetitionsresulted. Transplantation and rotation of limb buds to reverse either the dorso-ventral,antero-posterior or both axes resulted in the induction of supernumerary limbs in a large proportion of cases. Such regulatory behaviour of axolotl limb buds is in contrast to the mosaic nature of chick limbs and as a result, theories such as the progress-zone theory which have been formulated on the basis of data from chick limbs are not relevant togeneral principles of vertebrate limb development. Possible reasons for the diverse behaviour between the two systems are discussed.

Experiments on Anuran limb buds and their significance for principles of vertebrate limb development

Development ◽  
1981 ◽  
Vol 63 (1) ◽  
pp. 243-265
Author(s):  
M. Maden
Keyword(s):  
Limb Development ◽  
Rana Temporaria ◽  
Limb Bud ◽  
Limb Buds ◽  
Dorsoventral Axis ◽  
Vertebrate Limb ◽  
Vertebrate Limb Development ◽  
Supernumerary Limbs ◽  
Standard Set ◽  
And Inversion

A standard set of six experiments performed on the limb buds of two species of Anurans - Rana temporaria and Xenopus laevis -are described. The experiments are limb-bud amputation, distal to proximal shifts, proximal to distal shifts, inversion of the dorsoventral axis inversion of the anteroposterior axis and inversion of both axes. The results are compared to those previously reported for Urodeles and chicks to determine whether any principles of vertebrate limb development can be formulated. It appears that the proximodistal axis becomes increasingly mosaic from the Urodeles through Anurans to chicks. In the transverse axes however, there is much more uniformity of behaviour in the production of supernumerary limbs. The relation between the type of limb development (regulative or mosaic) and the subsequent regenerative powers of the adult limb is discussed.

scholarly journals Formin isoforms are differentially expressed in the mouse embryo and are required for normal expression of fgf-4 and shh in the limb bud

Development ◽  
1995 ◽  
Vol 121 (10) ◽  
pp. 3151-3162 ◽  
Author(s):  
D.C. Chan ◽  
A. Wynshaw-Boris ◽  
P. Leder
Keyword(s):  
Limb Development ◽  
Expression Patterns ◽  
Apical Ectodermal Ridge ◽  
Limb Bud ◽  
Amino Terminus ◽  
Ureteric Bud ◽  
Mrna Isoforms ◽  
Distal Limb ◽  
Limb Buds ◽  
Developing Kidney

Mice homozygous for the recessive limb deformity (ld) mutation display both limb and renal defects. The limb defects, oligodactyly and syndactyly, have been traced to improper differentiation of the apical ectodermal ridge (AER) and shortening of the anteroposterior limb axis. The renal defects, usually aplasia, are thought to result from failure of ureteric bud outgrowth. Since the ld locus gives rise to multiple RNA isoforms encoding several different proteins (termed formins), we wished to understand their role in the formation of these organs. Therefore, we first examined the embryonic expression patterns of the four major ld mRNA isoforms. Isoforms I, II and III (all containing a basic amino terminus) are expressed in dorsal root ganglia, cranial ganglia and the developing kidney including the ureteric bud. Isoform IV (containing an acidic amino terminus) is expressed in the notochord, the somites, the apical ectodermal ridge (AER) of the limb bud and the developing kidney including the ureteric bud. Using a lacZ reporter assay in transgenic mice, we show that this differential expression of isoform IV results from distinct regulatory sequences upstream of its first exon. These expression patterns suggest that all four isoforms may be involved in ureteric bud outgrowth, while isoform IV may be involved in AER differentiation. To define further the developmental consequences of the ld limb defect, we analyzed the expression of a number of genes thought to play a role in limb development. Most significantly, we find that although the AERs of ld limb buds express several AER markers, they do not express detectable levels of fibroblast growth factor 4 (fgf-4), which has been proposed to be the AER signal to the mesoderm. Thus we conclude that one or more formins are necessary to initiate and/or maintain fgf-4 production in the distal limb. Since ld limbs form distal structures such as digits, we further conclude that while fgf-4 is capable of supporting distal limb outgrowth in manipulated limbs, it is not essential for distal outgrowth in normal limb development. In addition, ld limbs show a severe decrease in the expression of several mesodermal markers, including sonic hedgehog (shh), a marker for the polarizing region and Hoxd-12, a marker for posterior mesoderm. We propose that incomplete differentiation of the AER in ld limb buds leads to reduction of polarizing activity and defects along the anteroposterior axis.

scholarly journals Experimental studies on the differentiation of embryonic tissues growing in vivo and in vitro .—II. The development of the isolated early embryonic eye of the fowl when cultivated in vitro

1926 ◽  
Vol 100 (703) ◽  
pp. 273-283 ◽  
Keyword(s):  
Medical Research ◽  
Research Council ◽  
Medical Research Council ◽  
Experimental Studies ◽  
Limb Bud ◽  
Progressive Development ◽  
Embryonic Tissues ◽  
Self Differentiation

In a previous communication (Strangeways and Fell, 1926) it was shown that if the undifferentiated limb-bud of the embryonic Fowl was cultivated in vitro , it underwent a considerable amount of progressive development. This capacity for independent development in vitro possessed by an isolated organ has been further investigated, and for these later experiments the writers have employed the early embryonic eye, a structure endowed with more complex potentialities than the limb-bud. As a result of these experiments it was found that the eyes of young Fowl embryos possess, in a remarkable degree, the faculty for self-differentiation in vitro and for “organotypic” growth as defined by Maximow (1925). The previous work on organotypic growth in vitro has already been briefly outlined in the writers’ earlier paper and need not be discussed here. The expenses connected with the experiments described in this communication were met by the Medical Research Council, to whom the writers desire to express their thanks.

Sign in / Sign up

Export Citation Format

Share Document