The International journal of developmental biology
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This review summarizes recent advances in leg regeneration research, focusing on the cricket Gryllus bimaculatus. Recent studies have revealed molecular mechanisms on blastema formation, establishment of positional information, and epigenetic regulation during leg regeneration. Especially, these studies have provided molecular bases in classical conceptual models such as the polar coordinate model, the intercalation model, the boundary model, the steepness model, etc., which were proposed to interpret regeneration processes of the cockroach legs. ⋯ For the molecular mechanism of intercalation of the missing structures between the amputated position and the most distal one, Dachsous/Fat (Ds/Ft) steepness model has been proposed, in which the Ds/Ft pathway maintains positional information and determines leg size through dac expression. This model was theoretically verified to interpret the experimental results obtained with cricket legs. Availability of whole-genome sequence information, regeneration-dependent RNA interference, and genome editing technique will have the cricket be an ideal model system to reveal gene functions in leg regeneration.