Novel function of Hox13 in regulating outgrowth of the newt hindlimb bud through interaction with Fgf10 and Tbx4.

5'Hox genes regulate pattern formation along the axes of the limb. Previously, we showed that Hoxa13/Hoxd13 double-mutant newts lacked all digits of the forelimbs during development and regeneration, showing that newt Hox13 is necessary for digit formation in development and regeneration. In addition, we found another unique phenotype.

Appendage-restricted gene induction using a heated agarose gel for studying regeneration in metamorphosed Xenopus laevis and Pleurodeles waltl.

Amphibians and fish often regenerate lost parts of their appendages (tail, limb, and fin) after amputation. Limb regeneration in adult amphibians provides an excellent model for appendage (limb) regeneration through 3D morphogenesis along the proximodistal, dorsoventral, and anteroposterior axes in mammals, because the limb is a homologous organ among amphibians and mammals. However, manipulating gene expression in specific appendages of adult amphibians remains difficult; this in turn hinders elucidation of the molecular mechanisms underlying appendage regeneration.

Newt Hoxa13 has an essential and predominant role in digit formation during development and regeneration.

The 5'Hox genes play crucial roles in limb development and specify regions in the proximal-distal axis of limbs. However, there is no direct genetic evidence that Hox genes are essential for limb development in non-mammalian tetrapods or for limb regeneration. Here, we produced single to quadruple Hox13 paralog mutants using the CRISPR/Cas9 system in newts (Pleurodeles waltl), which have strong regenerative capacities, and also produced germline mutants.

Upstream regulation for initiation of restricted Shh expression in the chick limb bud.

Background: The organizing center, which serves as a morphogen source, has crucial functions in morphogenesis in animal development. The center is necessarily located in a certain restricted area in the morphogenetic field, and there are several ways in which an organizing center can be restricted. The organizing center for limb morphogenesis, the ZPA (zone of polarizing activity), specifically expresses the Shh gene and is restricted to the posterior region of the developing limb bud.

Functional roles of Aves class-specific cis-regulatory elements on macroevolution of bird-specific features.

Unlike microevolutionary processes, little is known about the genetic basis of macroevolutionary processes. One of these magnificent examples is the transition from non-avian dinosaurs to birds that has created numerous evolutionary innovations such as self-powered flight and its associated wings with flight feathers. By analysing 48 bird genomes, we identified millions of avian-specific highly conserved elements (ASHCEs) that predominantly (>99%) reside in non-coding regions.

AP-2β is a transcriptional regulator for determination of digit length in tetrapods.

The species-specific morphology of digits in the tetrapod limb, including the length and number of metacarpal, metatarsal, and phalangeal bones, suggests that a common developmental mechanism for digit formation is modified in a species-specific manner. Here, we examined the function of the AP-2β transcription factor in regulating digit length in the chicken autopod. Mutations in the gene encoding AP-2β are associated with Char syndrome, a human autosomal dominant disorder.