Hyperpigmentation in the Silkie fowl correlates with abnormal migration of fate-restricted melanoblasts and loss of environmental barrier molecules

Neural crest melanoblasts display unique navigational abilities enabling them to colonize the dorsal path between ectoderm and somite. One signal shown here to elicit melanoblast migration is a chemotactic cue supplied by the emerging dermis. Until dermis emerges, melanoblasts fail to enter the dorsal path. The dermis emerges from a site that is too distant to stimulate migration by cell contact. Instead, surgeries show that dermis elicits migration from a distance. When dermis is grafted distally, neural crest cells enter the path precociously. Moreover, large grafts recruit melanoblasts from the control sides (without increasing crest cell numbers) as well as a few crest cells from ventral somite. Because other grafted tissues fail to stimulate migration, the dermis stimulus is specific. This report is the first documentation that trunk neural crest cells can be guided chemotactically. It also extends evidence that migration is exquisitely sensitive to temporal-spatial patterns of somite morphogenesis. Developmental Dynamics 229:99 -108, 2004.

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Long‐distance cue from emerging dermis stimulates neural crest melanoblast migration

Tosney

2003

“…The Silkie (Slk) is an ancient chicken breed (Faraco et al, 2001) that has polydactylous feet and expresses ectopic Shh as well as expression of genes downstream of Shh signalling, Hoxd13 and Bmp2, in the anterior leg bud from stage 25HH (Arisawa et al, 2006). Slk polydactyly is an autosomal-dominant trait with some variability from an extra phalanx in digit 1 (e.g., Fig.…”

Section: Introductionmentioning

confidence: 99%

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

Dunn

Paton

Clelland

et al. 2011

Point mutations in the intronic ZRS region of Lmbr1, a limb specific cis-regulatory element of Sonic hedgehog (Shh), are associated with polydactyly in humans, cats, and mice. We and others have recently mapped the dominant preaxial polydactyly (Po) locus in Silkie chickens to a single nucleotide polymorphism (SNP) in the ZRS region. Using polymorphisms in the chicken Shh sequence, we confirm that the ZRS region directly regulates Shh expression in the developing limb causing ectopic Shh expression in the anterior leg, prolonged Shh expression in the posterior limb, and allelic imbalance between wt and Slk Shh alleles in heterozygote limbs. Using Silkie legs, we have explored the consequences of increased Shh expression in the posterior leg on the patterning of the toes, and the induction of preaxial polydactyly.

“…For example, NC cells isolated from the ventral pathway do not give rise to melanocytes when explanted in culture (Reedy et al, 1998). Also, a naturally occurring chick mutant whose pigment cells migrate ventrally has no ectopic neurogenesis (Faraco et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Neural crest cells retain their capability for multipotential differentiation even after lineage‐restricted stages

Motohashi

Yamanaka

Chiba

et al. 2011

Multipotency of neural crest cells (NC cells) is thought to be a transient phase at the early stage of their generation; after NC cells emerge from the neural tube, they are specified into the lineage‐restricted precursors. We analyzed the differentiation of early‐stage NC‐like cells derived from Sox10‐IRES‐Venus ES cells, where the expression of Sox10 can be visualized with a fluorescent protein. Unexpectedly, both the Sox10+/Kit− cells and the Sox10+/Kit+ cells, which were restricted in vivo to the neuron (N)‐glial cell (G) lineage and melanocyte (M) lineage, respectively, generated N, G, and M, showing that they retain multipotency. We generated mice from the Sox10‐IRES‐Venus ES cells and analyzed the differentiation of their NC cells. Both the Sox10+/Kit− cells and Sox10+/Kit+ cells isolated from these mice formed colonies containing N, G, and M, showing that they are also multipotent. These findings suggest that NC cells retain multipotency even after the initial lineage‐restricted stages. Developmental Dynamics 240:1681–1693, 2011. © 2011 Wiley‐Liss, Inc.