Evolution of limb development in cephalopod mollusks

AbstractCephalopod mollusks evolved numerous anatomical novelties, including arms and tentacles, but little is known about the developmental mechanisms underlying cephalopod limb evolution. Here we show that all three axes of cuttlefish limbs are patterned by the same signaling networks that act in vertebrates and arthropods, although they evolved limbs independently. In cuttlefish limb buds, Hedgehog is expressed anteriorly. Posterior transplantation of Hedgehog-expressing cells induced mirror-image limb duplications. Bmp and Wnt signals, which establish dorsoventral polarity in vertebrate and arthropod limbs, are similarly polarized in cuttlefish. Inhibition of Bmp2/4 dorsally caused ectopic expression of Notum, which marks the ventral sucker field, and ectopic sucker development. Cuttlefish also show proximodistal regionalization of Hth, Exd, Dll, Dac, Sp8/9, and Wnt expression, which delineates arm and tentacle sucker fields. These results suggest that cephalopod limbs evolved by parallel activation of a genetic program for appendage development that was present in the bilaterian common ancestor.

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Evolution of limb development in cephalopod mollusks

eLife ◽

10.7554/elife.43828 ◽

2019 ◽

Vol 8 ◽

Cited By ~ 8

Author(s):

Oscar A Tarazona ◽

Davys H Lopez ◽

Leslie A Slota ◽

Martin J Cohn

Keyword(s):

Ventral Sucker ◽

Limb Development ◽

Common Ancestor ◽

Ectopic Expression ◽

Mirror Image ◽

Signaling Networks ◽

Limb Buds ◽

Dorsoventral Polarity ◽

Developmental Mechanisms ◽

Parallel Activation

Cephalopod mollusks evolved numerous anatomical novelties, including arms and tentacles, but little is known about the developmental mechanisms underlying cephalopod limb evolution. Here we show that all three axes of cuttlefish limbs are patterned by the same signaling networks that act in vertebrates and arthropods, although they evolved limbs independently. In cuttlefish limb buds, Hedgehog is expressed anteriorly. Posterior transplantation of Hedgehog-expressing cells induced mirror-image limb duplications. Bmp and Wnt signals, which establish dorsoventral polarity in vertebrate and arthropod limbs, are similarly polarized in cuttlefish. Inhibition of Bmp2/4 dorsally caused ectopic expression of Notum, which marks the ventral sucker field, and ectopic sucker development. Cuttlefish also show proximodistal regionalization of Hth, Exd, Dll, Dac, Sp8/9, and Wnt expression, which delineates arm and tentacle sucker fields. These results suggest that cephalopod limbs evolved by parallel activation of a genetic program for appendage development that was present in the bilaterian common ancestor.

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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 ◽

10.1242/dev.115.2.629 ◽

1992 ◽

Vol 115 (2) ◽

pp. 629-637 ◽

Cited By ~ 3

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)

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

Development ◽

10.1242/dev.125.3.351 ◽

1998 ◽

Vol 125 (3) ◽

pp. 351-357 ◽

Cited By ~ 2

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.

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Identification of Autosomal Regions Involved in Drosophila Raf Function

Genetics ◽

10.1093/genetics/156.2.763 ◽

2000 ◽

Vol 156 (2) ◽

pp. 763-774 ◽

Cited By ~ 2

Author(s):

Willis Li ◽

Elizabeth Noll ◽

Norbert Perrimon

Keyword(s):

Limb Development ◽

Target Gene ◽

Biological Function ◽

Genetic Interaction ◽

Ectopic Expression ◽

Tor Signaling ◽

Downstream Effector ◽

Early Embryos ◽

Genomic Regions

Abstract Raf is an essential downstream effector of activated p21Ras (Ras) in transducing proliferation or differentiation signals. Following binding to Ras, Raf is translocated to the plasma membrane, where it is activated by a yet unidentified “Raf activator.” In an attempt to identify the Raf activator or additional molecules involved in the Raf signaling pathway, we conducted a genetic screen to identify genomic regions that are required for the biological function of Drosophila Raf (Draf). We tested a collection of chromosomal deficiencies representing ∼70% of the autosomal euchromatic genomic regions for their abilities to enhance the lethality associated with a hypomorphic viable allele of Draf, DrafSu2. Of the 148 autosomal deficiencies tested, 23 behaved as dominant enhancers of Draf Su2, causing lethality in Draf Su2 hemizygous males. Four of these deficiencies identified genes known to be involved in the Drosophila Ras/Raf (Ras1/Draf) pathway: Ras1, rolled (rl, encoding a MAPK), 14-3-3ϵ, and bowel (bowl). Two additional deficiencies removed the Drosophila Tec and Src homologs, Tec29A and Src64B. We demonstrate that Src64B interacts genetically with Draf and that an activated form of Src64B, when overexpressed in early embryos, causes ectopic expression of the Torso (Tor) receptor tyrosine kinase-target gene tailless. In addition, we show that a mutation in Tec29A partially suppresses a gain-of-function mutation in tor. These results suggest that Tec29A and Src64B are involved in Tor signaling, raising the possibility that they function to activate Draf. Finally, we discovered a genetic interaction between Draf Su2 and Df(3L)vin5 that revealed a novel role of Draf in limb development. We find that loss of Draf activity causes limb defects, including pattern duplications, consistent with a role for Draf in regulation of engrailed (en) expression in imaginal discs.

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The chicken polydactyly (Po) locus causes allelic imbalance and ectopic expression of Shh during limb development

Developmental Dynamics ◽

10.1002/dvdy.22623 ◽

2011 ◽

Vol 240 (5) ◽

pp. 1163-1172 ◽

Cited By ~ 36

Author(s):

Ian C. Dunn ◽

I. Robert Paton ◽

Allyson K. Clelland ◽

Sujith Sebastian ◽

Edward J. Johnson ◽

...

Keyword(s):

Limb Development ◽

Allelic Imbalance ◽

Ectopic Expression

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Mouse Wnt genes exhibit discrete domains of expression in the early embryonic CNS and limb buds

Development ◽

10.1242/dev.119.1.247 ◽

1993 ◽

Vol 119 (1) ◽

pp. 247-261 ◽

Cited By ~ 72

Author(s):

B.A. Parr ◽

M.J. Shea ◽

G. Vassileva ◽

A.P. McMahon

Keyword(s):

Limb Development ◽

Expression Patterns ◽

Limb Buds ◽

Expression Studies ◽

The Family ◽

The Central Nervous System ◽

Discrete Domains ◽

Early Developmental ◽

The Brain

Mutation and expression studies have implicated the Wnt gene family in early developmental decision making in vertebrates and flies. In a detailed comparative analysis, we have used in situ hybridization of 8.0- to 9.5-day mouse embryos to characterize expression of all ten published Wnt genes in the central nervous system (CNS) and limb buds. Seven of the family members show restricted expression patterns in the brain. At least three genes (Wnt-3, Wnt-3a, and Wnt-7b) exhibit sharp boundaries of expression in the forebrain that may predict subdivisions of the region later in development. In the spinal cord, Wnt-1, Wnt-3, and Wnt-3a are expressed dorsally, Wnt-5a, Wnt-7a, and Wnt-7b more ventrally, and Wnt-4 both dorsally and in the floor plate. In the forelimb primordia, Wnt-3, Wnt-4, Wnt-6 and Wnt-7b are expressed fairly uniformly throughout the limb ectoderm. Wnt-5a RNA is distributed in a proximal to distal gradient through the limb mesenchyme and ectoderm. Along the limb's dorsal-ventral axis, Wnt-5a is expressed in the ventral ectoderm and Wnt-7a in the dorsal ectoderm. We discuss the significance of these patterns of restricted and partially overlapping domains of expression with respect to the putative function of Wnt signalling in early CNS and limb development.

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Correlation of wing-leg identity in ectopic FGF-induced chimeric limbs with the differential expression of chick Tbx5 and Tbx4

Development ◽

10.1242/dev.125.1.51 ◽

1998 ◽

Vol 125 (1) ◽

pp. 51-60 ◽

Cited By ~ 5

Author(s):

H. Ohuchi ◽

J. Takeuchi ◽

H. Yoshioka ◽

Y. Ishimaru ◽

K. Ogura ◽

...

Keyword(s):

Growth Factor ◽

Fibroblast Growth Factor ◽

Expression Patterns ◽

Ectopic Expression ◽

Limb Bud ◽

Chick Embryos ◽

Fibroblast Growth ◽

Limb Buds ◽

Specific Position

It has been reported that members of the fibroblast growth factor (FGF) family can induce additional limb formation in the flank of chick embryos. The phenotype of the ectopic limb depends on the somite level at which it forms: limbs in the anterior flank resemble wings, whereas those in the posterior flank resemble legs. Ectopic limbs located in the mid-flank appear chimeric, possessing characteristics of both wings and legs; feather buds are present in the anterior halves with scales and claws in the posterior halves. To study the mechanisms underlying the chimerism of these additional limbs, we cloned chick Tbx5 and Tbx4 to use as forelimb and hindlimb markers and examined their expression patterns in FGF-induced limb buds. We found that Tbx5 and Tbx4 were differentially expressed in the anterior and posterior halves of additional limb buds in the mid-flank, respectively, consistent with the chimeric patterns of the integument. A boundary of Tbx5/Tbx4 exists in all ectopic limbs, indicating that the additional limbs are essentially chimeric, although the degree of chimerism is dependent on the position. The boundary of Tbx5/Tbx4 expression is not fixed at a specific position within the interlimb region, but dependent upon where FGF was applied. Since the ectopic expression patterns of Tbx5/Tbx4 in the additional limbs are closely correlated with the patterns of their chimeric phenotypes, it is likely that Tbx5 and Tbx4 expression in the limb bud is involved in determination of the forelimb and hindlimb identities, respectively, in vertebrates.

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Coexpression of the homeobox genes Distal-less and homothorax determines Drosophila antennal identity

Development ◽

10.1242/dev.127.2.209 ◽

2000 ◽

Vol 127 (2) ◽

pp. 209-216 ◽

Cited By ~ 4

Author(s):

P.D. Dong ◽

J. Chu ◽

G. Panganiban

Keyword(s):

Limb Development ◽

Ectopic Expression ◽

Homeobox Genes ◽

Biochemical Properties ◽

The Body ◽

Critical Function ◽

Genital Disc ◽

Identity Based

The Distal-less gene is known for its role in proximodistal patterning of Drosophila limbs. However, Distal-less has a second critical function during Drosophila limb development, that of distinguishing the antenna from the leg. The antenna-specifying activity of Distal-less is genetically separable from the proximodistal patterning function in that certain Distal-less allelic combinations exhibit antenna-to-leg transformations without proximodistal truncations. Here, we show that Distal-less acts in parallel with homothorax, a previously identified antennal selector gene, to induce antennal differentiation. While mutations in either Distal-less or homothorax cause antenna-to-leg transformations, neither gene is required for the others expression, and both genes are required for antennal expression of spalt. Coexpression of Distal-less and homothorax activates ectopic spalt expression and can induce the formation of ectopic antennae at novel locations in the body, including the head, the legs, the wings and the genital disc derivatives. Ectopic expression of homothorax alone is insufficient to induce antennal differentiation from most limb fields, including that of the wing. Distal-less therefore is required for more than induction of a proximodistal axis upon which homothorax superimposes antennal identity. Based on their genetic and biochemical properties, we propose that Homothorax and Extradenticle may serve as antenna-specific cofactors for Distal-less.

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Evolutionary developmental biology of the tetrapod limb

Development ◽

10.1242/dev.1994.supplement.163 ◽

1994 ◽

Vol 1994 (Supplement) ◽

pp. 163-168

Author(s):

J. Richard Hinchliffe

Keyword(s):

Gene Expression ◽

Developmental Biology ◽

Early Development ◽

Homeobox Gene ◽

Evolutionary Developmental Biology ◽

Epigenetic Factors ◽

Limb Buds ◽

Developmental Mechanisms ◽

Direct Gene ◽

Embryological Analysis

New insights into the origin of the tetrapod limb, and its early development and patterning, are emerging from a variety of fields. A wide diversity of approaches was reported at the BSDB Spring Symposium on `The Evolution of Developmental Mechanisms' (Edinburgh, 1994); here I review the contributions these various approaches have made to understanding the evolutionary developmental biology of the tetrapod limb. The fields covered included palaeontology, descriptive embryology, experimental embryological analysis of interactions within developing limbs plus description and manipulation of homeobox gene expression in early limb buds. Concepts are equally varied, sometimes conflicting, sometimes overlapping. Some concern the limb `archetype' (can the palaeontologists and morphologists still define this with precision? how far is there a limb developmental bauplan?); others are based on identification of epigenetic factors (eg secondary inductions), as generating pattern; while yet others assume a direct gene-morphology relationship. But all the contributors ask the same compelling question: can we explain both the similarity (homology) and variety of tetrapod limbs (and the fins of the Crossopterygians) in terms of developmental mechanisms?

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