Studies With Talpid2, an Embryonic Lethal of the Fowl

Abbott, Ursula K.; Taylor, Lewis W.; Abplanalp, Hans

doi:10.1093/oxfordjournals.jhered.a106988

Cited by 46 publications

(31 citation statements)

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“…Ta embryos show various aberrant morphological traits including a reduction in length of the limbs, extreme polydactyly, and some webbing between the digits. Abbott and her colleagues identified a second talpid mutant (Abbott et al 1960). The phenotype of this mutant resembles Cole's talpid in abnormal limb morphology and body form; however, there are differences in the brain and associated neural structures (Abbott et al 1960).…”

Section: An Avian Model Of Polydactylymentioning

confidence: 99%

“…Abbott and her colleagues identified a second talpid mutant (Abbott et al 1960). The phenotype of this mutant resembles Cole's talpid in abnormal limb morphology and body form; however, there are differences in the brain and associated neural structures (Abbott et al 1960). Unfortunately, Cole's talpid went extinct before the second strain was recognized, and this fact, along with the phenotypic differences between these mutant forms, necessitated that the second line be designated talpid 2 (ta 2 ).…”

Section: An Avian Model Of Polydactylymentioning

confidence: 99%

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From head to toe: conservation of molecular signals regulating limb and craniofacial morphogenesis

Schneider

Helms

1999

Cell and Tissue Research

100

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Recent evidence indicates that many molecules involved in generating and patterning the limbs also play a role during craniofacial morphogenesis. On the surface, this is an unexpected finding given that these regions of the body have separate evolutionary origins, are composed of different embryonic tissues, and are quite dissimilar in their anatomy. Results from several experiments involving Sonic hedgehog and retinoic acid point to a remarkable conservation of the signaling pathways mediated by these morphogens across multiple organ systems. Moreover, mutants such as the extra-toes and doublefoot mouse, and the talpid chicken also provide insights on common developmental processes that underlie the formation of the limbs and face. The identification of highly conserved aspects of morphogenesis is important for understanding fundamental mechanisms of development, as well as for revealing the common denominator of countless birth defects and providing new strategies for their prevention and cure.

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Section: An Avian Model Of Polydactylymentioning

confidence: 99%

Section: An Avian Model Of Polydactylymentioning

confidence: 99%

From head to toe: conservation of molecular signals regulating limb and craniofacial morphogenesis

Schneider

Helms

1999

Cell and Tissue Research

100

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“…TulpidL is a simple Mendelian autosomal recessive mutation which affects the mesoderm (Abbott et al, 1959;Goetinck and Abbott, 1964;Dvorak and Fallon, 1991). Tulpid2 limbs have a single long bone in the upper limb, two long bones in the forelimb, and many digits distally.…”

Section: Introductionmentioning

confidence: 99%

“…Tulpid2 limbs have a single long bone in the upper limb, two long bones in the forelimb, and many digits distally. Therefore, the ectodermal-mesodermal interactions mediating proximodistal development appear to be normal in tu2 limb buds (Abbott et al, 1959;Goetinck and Abbott, 1964;Dvorak and Fallon, 1991). However, tu2 limbs have abnormal anteroposterior patterning.…”

Section: Introductionmentioning

confidence: 99%

Talpid² limb bud mesoderm does not express GHox‐8 and has an altered expression pattern of GHox‐7

Krabbenhoft

Fallon

1992

Developmental Dynamics

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We have studied the expression patterns of the chick homeobox-containing genes, GHox-7 and GHox-8, in the tuZpid2 @a2) chick mutant whose limbs have abnormal pattern. These studies provide new insight into how homeobox gene expression and limb patterning may be related. This is the first study demonstrating a natural change in GHox-7 and GHox-8 along the anteroposterior axis. While GHox-7 is expressed asymmetrically in normal limb buds, it is expressed at a uniform level across the anteroposterior axis of tu2 limb buds. GHox-8 is expressed in anterior mesoderm of normal limb buds, but is undetectable in tu2 limb bud mesoderm. These data are consistent with the subtle anteroposterior polarity in tu2 limbs, and allow us to propose that tu2 limb buds lack anterior positional information, but have a narrow range of posterior positional values. We suggest that in normal limb buds GHox-8 may establish the anterior limb bud boundary. Furthermore, we point out that coexpression of GHox-7 and GHox-8 in normal anterior limb bud mesoderm can be correlated with the reduced apical ridge maintenance activity of this tissue, while the lack of coexpression in tu2 limb buds is correlated with the strong ridge maintenance activity in the mutant's anterior limb bud mesoderm. Last, tu2 limbs contain no dying cells in their anterior and posterior border mesoderm; nevertheless, they express GHox-7 in these regions. These data challenge the proposal that this gene determines cell death.

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“…Tulpid' (tu') is a homozygous recessive lethal mutation with profound effects on anteroposterior limb pattern (Abbott et al, 1959). None of the limb skeletal elements of affected embryos has normal morphology.…”

Section: Introductionmentioning

confidence: 99%

The talpid² chick limb has weak polarizing activity and can respond to retinoic acid and polarizing zone signal

Dvorak

Fallon

1992

Developmental Dynamics

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The tuZpi8 @a2) chick mutant has wide, polydactylous wings and legs. TuZpid2 limb cartilages have abnormal morphology and a very subtle anteroposterior polarity. Specifically, posterior ta2 limb structures are identifiable, while more anterior cartilages are less distinctive. Here, we investigate the development of anteroposterior limb pattern in the tu2 embryo. We show that tu2 posterior limb bud mesoderm is capable of respecifying the anteroposterior axis of a normal wing. However, the average duplication obtained after grafting a tu2 polarizing region was significantly less than the average duplication formed after a graft of normal wing bud polarizing zone. Thus, polarizing activity appears to be weak in tu2. Grafts of normal polarizing zone to the posterior edge of tu2 wing buds had no effect on the tu2 phenotype. This result suggests that a weakly functioning polarizing signal does not account for the altered anteroposterior polarity in tu2 limbs, and that normal polarizing zone activity is not sufficient for formation of normal limb bud cartilages. We demonstrated that transmission of a polarizing signal through the tu2 limb mesoderm was normal. In addition, tu2 anterior border mesoderm had no polarizing activity. We also assessed the ability of tu2 limb bud mesoderm to respond to a polarizing signal. Either normal polarizing zone tissue or a bead containing retinoic acid was placed at the anterior edge of tu2 wing buds at stages 18-23. Both polarizing zone and retinoic acid caused respecification of the tu2 wing anteroposterior axis. The result was that a tu2 ulna replaced the radius, and the most posterior digit was duplicated anteriorly. Limb cartilages with normal morphology never formed. When a bead containing retinoic acid was placed at the posterior edge of tu2 wing buds, there was no effect on anteroposterior pattern. However, beads with retinoic acid always caused a reduction in the number of tu2 wing digits which formed, whether the beads were placed at the anterior or posterior edge of the developing tu2 limb.

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Studies With Talpid2, an Embryonic Lethal of the Fowl

Cited by 46 publications

References 0 publications

From head to toe: conservation of molecular signals regulating limb and craniofacial morphogenesis

From head to toe: conservation of molecular signals regulating limb and craniofacial morphogenesis

Talpid² limb bud mesoderm does not express GHox‐8 and has an altered expression pattern of GHox‐7

The talpid² chick limb has weak polarizing activity and can respond to retinoic acid and polarizing zone signal

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Studies With Talpid2, an Embryonic Lethal of the Fowl

Cited by 46 publications

References 0 publications

From head to toe: conservation of molecular signals regulating limb and craniofacial morphogenesis

From head to toe: conservation of molecular signals regulating limb and craniofacial morphogenesis

Talpid2 limb bud mesoderm does not express GHox‐8 and has an altered expression pattern of GHox‐7

The talpid2 chick limb has weak polarizing activity and can respond to retinoic acid and polarizing zone signal

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Talpid² limb bud mesoderm does not express GHox‐8 and has an altered expression pattern of GHox‐7

The talpid² chick limb has weak polarizing activity and can respond to retinoic acid and polarizing zone signal