The target tissue of limb-bud polarizing activity in the induction of supernumerary structures

Development ◽  
1979 ◽  
Vol 53 (1) ◽  
pp. 67-73
Author(s):  
Jeffrey A. Maccabe ◽  
Brenda W. Parker
Keyword(s):  
Limb Bud ◽  
Target Tissue ◽  
Posterior Border ◽  
Posterior Limb ◽  
Anteroposterior Axis

When polarizing mesoderm from the posterior border of the 4-day chick limb bud is placed adjacent to anterior limb mesoderm and ectodermal ridge, the anterior ridge thickens and mesodermal outgrowth ensues, resulting in supernumerary limb structures. This apposition of anterior and posterior limb tissues can be accomplished by cutting off the apical one third of the limb bud and reimplanting it on the stump with its anteroposterior axis reversed. The preaxial response to polarizing activity can be obtained after only 12–18 h in the reoriented position. Reversed apical mesoderm develops supernumerary digits when combined with untreated ectoderm. The reciprocal combination, reversed ectoderm and untreated mesoderm, fails to develop supernumerary structures. We have interpreted this as evidence that, in inducing supernumerary limb structures, polarizing activity actsonly on the mesoderm.

Pattern regulation and the origin of extra parts following axial misalignments in the urodele limb bud

Development ◽  
1980 ◽  
Vol 60 (1) ◽  
pp. 33-55
Author(s):  
Stephen D. Thoms ◽  
John F. Fallon
Keyword(s):  
Host Tissue ◽  
Limb Bud ◽  
Substantial Contribution ◽  
Posterior Border ◽  
Anterior Border ◽  
Dorsoventral Polarity ◽  
Anteroposterior Axis ◽  
Graft Tissue ◽  
Salamander Species ◽  
Pattern Regulation

Pattern regulation following axial misalignments in the stage-38+to stage-40 urodele limb bud was studied on one newt and two salamander species. Grafts of the distal tip of the limb bud were made to the stump of a host limb bud from which a similar piece had been removed. The grafts were positioned with either their anteroposterior, dorsoventral, or both of these axes reversed with respect to the host axes. Mirror-imaged duplications, positioned posteriorly or both anteriorly and posteriorly, occurred nearly all (96%) of the time when the anteroposterior axis was reversed. Dorsoventral axial misalignment rarely promoted the generation of mirror-imaged duplications (8%) but did affect the organization along the anteroposterior axis by causing a serial repetition of either digit 2 or digit 3. Regulation, therefore, does not always occur along each axis independently of the others. Consistent with the data derived from reversing individual axes, most of the duplications which occurred when both axes were reversed were in the anteroposterior plane. Some were in the dorsoventral plane, and a few had intermediate positions. Of these duplications a few were neither right nor left hands, rather they were of mixed handedness with a change in the dorsoventral polarity from the anterior border to the posterior border. Whether extra parts which result from axial misalignments arise from the graft, the host, or both the graft and the host was investigated using heteroplastic grafts and grafts exchanged between triploid and diploid axolotls. Duplications were found to have cellular contributions from both the graft and the host. In some cases one source would dominate but usually both made a substantial contribution. The diploid-triploid material suggests that a considerable mixing of host and graft cells may occur in duplications. Additionally, some digits of the graft sequence of digits can be derived from host tissue. The extra digit in those hands displaying a serial repetition was derived from host tissue in some cases and graft tissue in other cases.

Posterior apical ectodermal ridge removal in the chick wing bud triggers a series of events resulting in defective anterior pattern formation

Development ◽  
1987 ◽  
Vol 101 (3) ◽  
pp. 501-515 ◽  
Author(s):  
W.L. Todt ◽  
J.F. Fallon
Keyword(s):  
Cell Death ◽  
Apical Ectodermal Ridge ◽  
Limb Bud ◽  
Direct Result ◽  
Posterior Border ◽  
Posterior Portion ◽  
Mesodermal Cell ◽  
Posterior Limb ◽  
Survival And Development ◽  
Wing Bud

The ability of the anterior apical ectodermal ridge to promote outgrowth in the chick wing bud when disconnected from posterior apical ridge was examined by rotating the posterior portion of the stage-19/20 to stage-21 wing bud around its anteroposterior axis. This permitted contact between the anterior and posterior mesoderm, without removing wing bud tissue. In a small but significant number of cases (10/54), anterior structures (digit 2) formed spatially isolated from posterior structures (digits 3 and 4). Thus, continuity with posterior ridge is not a prerequisite for anterior-ridge function in the wing bud. Nevertheless, posterior-ridge removal does result in anterior limb truncation. To investigate events leading to anterior truncation, we examined cell death patterns in the wing bud following posterior-ridge removal. We observed an abnormal area of necrosis along the posterior border of the wing bud at 6–12 h following posterior-ridge removal. This was followed by necrosis in the distal, anterior mesoderm at 48 h postoperatively and subsequent anterior truncation. Clearly, healthy posterior limb bud mesoderm is needed for anterior limb bud survival and development. We propose that anterior truncation is the direct result of anterior mesodermal cell death and that this may not be related to positional specification of anterior cells. In our view, cell death of anterior mesoderm, after posterior mesoderm removal, should not be used as evidence for a role in position specification by the polarizing zone during the limb bud stages of development. We suggest that the posterior mesoderm that maintains the anterior mesoderm need not be restricted to the mapped polarizing zone, but is more extensively distributed in the limb bud.

FGF-4 maintains polarizing activity of posterior limb bud cells in vivo and in vitro

Development ◽  
1993 ◽  
Vol 119 (1) ◽  
pp. 199-206 ◽  
Author(s):  
A. Vogel ◽  
C. Tickle
Keyword(s):  
Posterior Margin ◽  
Anterior Margin ◽  
Marked Decrease ◽  
Mesenchymal Cells ◽  
Apical Ectodermal Ridge ◽  
Limb Bud ◽  
Posterior Limb ◽  
Vertebrate Limb

The polarizing region is a major signalling tissue involved in patterning the tissues of the vertebrate limb. The polarizing region is located at the posterior margin of the limb bud and can be recognized by its ability to induce additional digits when grafted to the anterior margin of a chick limb bud. The signal from the polarizing region operates at the tip of the bud in the progress zone, a zone of undifferentiated mesenchymal cells, maintained by interactions with the apical ectodermal ridge. A number of observations have pointed to a link between the apical ectodermal ridge and signalling by the polarizing region. To test this possibility, we removed the posterior apical ectodermal ridge of chick wing buds and assayed posterior mesenchyme for polarizing activity. When the apical ectodermal ridge is removed, there is a marked decrease in polarizing activity of posterior cells. The posterior apical ectodermal ridge is known to express FGF-4 and we show that the decrease in polarizing activity of posterior cells of wing buds that normally follows ridge removal can be prevented by implanting a FGF-4-soaked bead. Furthermore, we show that both ectoderm and FGF-4 maintain polarizing activity of limb bud cells in culture.

Evidence that members of the Cut/Cux/CDP family may be involved in AER positioning and polarizing activity during chick limb development

Development ◽  
2000 ◽  
Vol 127 (23) ◽  
pp. 5133-5144
Author(s):  
A.T. Tavares ◽  
T. Tsukui ◽  
J.C. Izpisua Belmonte
Keyword(s):  
Limb Development ◽  
Limb Bud ◽  
Wing Margin ◽  
Lateral Plate ◽  
Posterior Limb ◽  
Downstream Target ◽  
Notch Pathways ◽  
Specialized Region ◽  
Dorsoventral Boundary ◽  
Cycle Regulation

In vertebrates, the apical ectodermal ridge (AER) is a specialized epithelium localized at the dorsoventral boundary of the limb bud that regulates limb outgrowth. In Drosophila, the wing margin is also a specialized region located at the dorsoventral frontier of the wing imaginal disc. The wingless and Notch pathways have been implicated in positioning both the wing margin and the AER. One of the nuclear effectors of the Notch signal in the wing margin is the transcription factor cut. Here we report the identification of two chick homologues of the Cut/Cux/CDP family that are expressed in the developing limb bud. Chick cux1 is expressed in the ectoderm outside the AER, as well as around ridge-like structures induced by (β)-catenin, a downstream target of the Wnt pathway. cux1 overexpression in the chick limb results in scalloping of the AER and limb truncations, suggesting that Cux1 may have a role in limiting the position of the AER by preventing the ectodermal cells around it from differentiating into AER cells. The second molecule of the Cut family identified in this study, cux2, is expressed in the pre-limb lateral plate mesoderm, posterior limb bud and flank mesenchyme, a pattern reminiscent of the distribution of polarizing activity. The polarizing activity is determined by the ability of a certain region to induce digit duplications when grafted into the anterior margin of a host limb bud. Several manipulations of the chick limb bud show that cux2 expression is regulated by retinoic acid, Sonic hedgehog and the posterior AER. These results suggest that Cux2 may have a role in generating or mediating polarizing activity. Taking into account the probable involvement of Cut/Cux/CDP molecules in cell cycle regulation and differentiation, our results raise the hypothesis that chick Cux1 and Cux2 may act by modulating proliferation versus differentiation in the limb ectoderm and polarizing activity regions, respectively.

scholarly journals COINCINDENT ACTIVATION OF THE WNT AND SHH PATHWAYS BY FGF IN THE POSTERIOR LIMB BUD

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Jonathan M Van Arsdale ◽  
Jennifer M Feenstra ◽  
Charmaine U Pira ◽  
Kerby C Oberg
Keyword(s):  
Limb Bud ◽  
Posterior Limb

Interaction between the proximo-distal and antero-posterior co-ordinates of positional value during the specification of positional information in the early development of the chick limb-bud

Development ◽  
1974 ◽  
Vol 32 (1) ◽  
pp. 227-237
Author(s):  
Dennis Summerbell
Keyword(s):  
Early Development ◽  
Anterior Margin ◽  
Positional Information ◽  
Apical Ectodermal Ridge ◽  
Limb Bud ◽  
Anteroposterior Axis ◽  
Zone Of Polarizing Activity ◽  
Positional Value ◽  
Special Region

The experiments examine the extent of reduplication of skeletal parts across the anteroposterior axis, following the transplantation of a zone of polarizing activity (ZPA) to the anterior margin of the limb-bud at successively later stages. Previous studies have suggested that the function of the apical ectodermal ridge (AER) is to maintain cells in a special region at the distal tip (the progress zone) labile, with respect to their positional value along the proximo-distal axis. Similarly, the results of these experiments demonstrate that cells in the progress zone are able to change their antero-posterior positional value under the influence of the grafted ZPA, while cells at more proximal levels remain unaffected. In turn, the ZPA may effect the activity of the AER and hence the progress zone.

scholarly journals Ectopic Expression ofMsx-2in Posterior Limb Bud Mesoderm Impairs Limb Morphogenesis While InducingBMP-4Expression, Inhibiting Cell Proliferation, and Promoting Apoptosis

1998 ◽  
Vol 197 (1) ◽  
pp. 12-24 ◽  
Author(s):  
Deborah Ferrari ◽  
Alexander C. Lichtler ◽  
ZhongZong Pan ◽  
Caroline N. Dealy ◽  
William B. Upholt ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Ectopic Expression ◽  
Limb Bud ◽  
Posterior Limb ◽  
Limb Morphogenesis

scholarly journals Intercalation and the cellular origin of supernumerary limbs in Xenopus

Development ◽  
1987 ◽  
Vol 99 (4) ◽  
pp. 521-526 ◽  
Author(s):  
K. Muneoka ◽  
E.H. Murad
Keyword(s):  
Limb Development ◽  
Limb Bud ◽  
Posterior Limb ◽  
Cellular Origin ◽  
Supernumerary Limbs ◽  
Anterior Posterior ◽  
Anterior Posterior Axis

The hypothesis that a specialized polarizing zone controls the pattern of the anterior-posterior axis during limb development in Xenopus has been tested by analysing the cellular contribution to supernumerary limbs. Supernumerary limbs were generated by grafting hindlimb buds contralaterally between X. borealis and X. laevis to appose anterior and posterior limb tissues. Cells derived from these two species of Xenopus are readily identified by staining with quinacrine. The analysis of cellular contribution showed that supernumerary limbs consist of approximately half anterior-derived (57%) and half posterior-derived (43%) cells. These data are not consistent with the polarizing zone theory but are consistent with the hypothesis that both supernumerary limbs and normally developing limbs arise from intercalary interactions between limb bud cells with different positional values.

Sign in / Sign up

Export Citation Format

Share Document