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.

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.

Myogenic cell movement in the developing avian limb bud in presence and absence of the apical ectodermal ridge (AER)

Development ◽  
1984 ◽  
Vol 80 (1) ◽  
pp. 105-125
Author(s):  
Madeleine Gumpel-Pinot ◽  
D. A. Ede ◽  
O. P. Flint
Keyword(s):  
Cell Migration ◽  
Cell Movement ◽  
Host Tissue ◽  
Apical Ectodermal Ridge ◽  
Limb Bud ◽  
Myogenic Cell ◽  
Myogenic Cells ◽  
Apical Direction ◽  
Wing Bud ◽  
Presence And Absence

Fragments of quail wing bud containing myogenic cells of somitic origin and fragments of quail sphlanchopleural tissue were introduced into the interior of the wing bud of fowl embryo hosts. No movement of graft into host tissue occurred in the control, but myogenic cells from the quail wing bud fragments underwent long migrations in an apical direction to become incorporated in the developing musculature of the host. When the apical ectodermal ridge (AER), together with some subridge mesenchyme, was removed at the time of grafting, no such cell migration occurred. The capacity of grafted myogenic cells to migrate in the presence of AER persists to H.H. stage 25, when myogenesis has begun, but premyogenic cells in the somites, which normally migrate out into the early limb bud, do not migrate when somite fragments are grafted into the wing bud. Coelomic grafts of apical and proximal wing fragments showed that apical sections of quail wing buds become invaded by myogenic cells of the host, but grafts from proximal wing bud regions do not.

The spatial and temporal dynamics of Sax1 (CHox3) homeobox gene expression in the chick's spinal cord

Development ◽  
1994 ◽  
Vol 120 (7) ◽  
pp. 1817-1828 ◽  
Author(s):  
P. Spann ◽  
M. Ginsburg ◽  
Z. Rangini ◽  
A. Fainsod ◽  
H. Eyal-Giladi ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Homeobox Gene ◽  
Primitive Streak ◽  
Neural Plate ◽  
Transverse Plane ◽  
Posterior Border ◽  
Anterior Border ◽  
Spatial And Temporal Dynamics ◽  
Specific Localization

Sax1 (previously CHox3) is a chicken homeobox gene belonging to the same homeobox gene family as the Drosophila NK1 and the honeybee HHO genes. Sax1 transcripts are present from stage 2 H&H until at least 5 days of embryonic development. However, specific localization of Sax1 transcripts could not be detected by in situ hybridization prior to stage 8-, when Sax1 transcripts are specifically localized in the neural plate, posterior to the hindbrain. From stages 8- to 15 H&H, Sax1 continues to be expressed only in the spinal part of the neural plate. The anterior border of Sax1 expression was found to be always in the transverse plane separating the youngest somite from the yet unsegmented mesodermal plate and to regress with similar dynamics to that of the segregation of the somites from the mesodermal plate. The posterior border of Sax1 expression coincides with the posterior end of the neural plate. In order to study a possible regulation of Sax1 expression by its neighboring tissues, several embryonic manipulation experiments were performed. These manipulations included: removal of somites, mesodermal plate or notochord and transplantation of a young ectopic notochord in the vicinity of the neural plate or transplantation of neural plate sections into the extraembryonic area. The results of these experiments revealed that the induction of the neural plate by the mesoderm has already occurred in full primitive streak embryos, after which Sax1 is autonomously regulated within the spinal part of the neural plate.

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.

Genes that control dorsoventral polarity affect gene expression along the anteroposterior axis of the Drosophila embryo

Development ◽  
1987 ◽  
Vol 99 (3) ◽  
pp. 327-332 ◽  
Author(s):  
S.B. Carroll ◽  
G.M. Winslow ◽  
V.J. Twombly ◽  
M.P. Scott
Keyword(s):  
Gene Expression ◽  
Cell Fate ◽  
Maternal Effect ◽  
Positional Information ◽  
Drosophila Embryo ◽  
Dorsoventral Polarity ◽  
Anteroposterior Axis ◽  
Positional Marker ◽  
Control Pattern ◽  
The Relationship

At least 13 genes control the establishment of dorsoventral polarity in the Drosophila embryo and more than 30 genes control the anteroposterior pattern of body segments. Each group of genes is thought to control pattern formation along one body axis, independently of the other group. We have used the expression of the fushi tarazu (ftz) segmentation gene as a positional marker to investigate the relationship between the dorsoventral and anteroposterior axes. The ftz gene is normally expressed in seven transverse stripes. Changes in the striped pattern in embryos mutant for other genes (or progeny of females homozygous for maternal-effect mutations) can reveal alterations of cell fate resulting from such mutations. We show that in the absence of any of ten maternal-effect dorsoventral polarity gene functions, the characteristic stripes of ftz protein are altered. Normally there is a difference between ftz stripe spacing on the dorsal and ventral sides of the embryo; in dorsalized mutant embryos the ftz stripes appear to be altered so that dorsal-type spacing occurs on all sides of the embryo. These results indicate that cells respond to dorsoventral positional information in establishing early patterns of gene expression along the anteroposterior axis and that there may be more significant interactions between the different axes of positional information than previously determined.

scholarly journals BARE SPOT LOCATION IN GLENOID CAVITY: COMPARISON BETWEEN ARTHROSCOPY AND CT SCAN

2020 ◽  
Vol 28 (5) ◽  
pp. 243-246
Author(s):  
MAX ROGÉRIO FREITAS RAMOS ◽  
PEDRO FILGUEIRAS HIDALGO ◽  
DIOGO FAGUNDES ◽  
YONDER ARCHANJO CHING SAN JUNIOR
Keyword(s):  
Posterior Margin ◽  
Three Dimensional ◽  
Glenoid Cavity ◽  
Posterior Border ◽  
Posterior Edge ◽  
Anterior Border ◽  
Level Of Evidence ◽  
Injury Repair ◽  
Bare Spot ◽  
Dimensional Reconstruction

ABSTRACT Objective: To assess whether Bare Spot is previously displaced by proportion (MEASURE BP-A × 1.25/MEASURE BP-P = 1). Methods: 35 patients with surgical indication for rotator cuff injury repair were evaluated. The distances from the Bare Spot to the anterior edge of the glenoid cavity (BS-A) and to the posterior edge (BS-P) were measured by arthroscopy and computed tomography with three-dimensional reconstruction of the scapula. Results: The distance from the Bare Spot to the anterior border (BS-A tc) was 11.6 mm with a median 12 mm; The distance to the posterior border (BS-P tc) was on average 15.5 mm with a median 15 mm. The distances from BS to anterior cavity edge measured by arthroscopy were on average (BS-A video) 12.25 mm with a median of 12 mm, and from BS to posterior edge (BS-P video) 16.25 mm on average with median 16 mm (p < 0.005). Conclusion: Bare Spot is displaced anteriorly at a proportion of 40% of the anterior margin and 60% of the posterior margin. Level of Evidence II - Development of diagnostic criteria on consecutive patients (with universally applied reference “gold standard”).

Role of dHAND in the anterior-posterior polarization of the limb bud: implications for the Sonic hedgehog pathway

Development ◽  
2000 ◽  
Vol 127 (10) ◽  
pp. 2133-2142 ◽  
Author(s):  
M. Fernandez-Teran ◽  
M.E. Piedra ◽  
I.S. Kathiriya ◽  
D. Srivastava ◽  
J.C. Rodriguez-Rey ◽  
...  
Keyword(s):  
Sonic Hedgehog ◽  
Limb Development ◽  
Mirror Image ◽  
Limb Bud ◽  
Bhlh Transcription Factor ◽  
Cardiovascular Development ◽  
Anterior Border ◽  
Lateral Plate ◽  
Shh Pathway ◽  
Anterior Posterior

dHAND is a basic helix-loop-helix (bHLH) transcription factor essential for cardiovascular development. Here we analyze its pattern of expression and functional role during chick limb development. dHAND expression was observed in the lateral plate mesoderm prior to emergence of the limb buds. Coincident with limb initiation, expression of dHAND became restricted to the posterior half of the limb bud. Experimental procedures that caused mirror-image duplications of the limb resulted in mirror-image duplications of the pattern of dHAND expression along the anterior-posterior axis. Retroviral overexpression of dHAND in the limb bud produced preaxial polydactyly, corresponding to mild polarizing activity at the anterior border. At the molecular level, misexpression of dHAND caused ectopic activation of members of the Sonic hedgehog (Shh) pathway, including Gli and Patched, in the anterior limb bud. A subset of infected embryos displayed ectopic anterior activation of Shh. Other factors implicated in anterior-posterior polarization of the bud such as the most 5′ Hoxd genes and Bmp2 were also ectopically activated at the anterior border. Our results indicate a role for dHAND in the establishment of anterior-posterior polarization of the limb bud.

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