Newts can normalize duplicated proximal–distal disorder during limb regeneration

Abstract

Background: Urodele animals can regenerate their limbs from the blastemas. The previous results of grafting proximal blastemas to distal limb levels (P to D transplantation) led to serial duplication of limb segments. However, it is unknown whether grafting to any distal levels in P to D transplantation causes serial duplication. In other words, it is unknown whether or not newt limbs can normalize such a kind of duplicated type of positional disorder in the proximal–distal axis. Therefore, we grafted the most proximal blastemas to various distal levels of the proximal–distal axis using newts (Pleurodeles waltl). The transgenic newts expressing green fluorescent protein or mCherry were used to clearly distinguish between donor and host tissues. Results: Normal segmental formation without duplication occurred in P to D transplantation within the stylopod. In addition, donor blastemas lost the fates of the stylopods, and the missing portion in the stylopod by amputation was restored by the insertion of host cells. In contrast, the blastemas from the stylopod formed whole limbs after transplantation to the tail. Conclusions: These results showed that urodele limbs can normalize the duplicated type of positional disorder within the stylopod by erasing a part of the fate in the blastemas. Developmental Dynamics 247:1276–1285, 2018. © 2018 Wiley Periodicals, Inc.

Remembering where we are: Positional information in salamander limb regeneration

“…Contrastingly, grafts of proximal blastemas to distal limbs typically produced a duplication of structures along the proximodistal axis, with little evidence of cells of the distal limb structures transforming to contribute to more proximal skeletal structures . Recent work, however, indicates some capacity for self‐correction in salamanders when proximal blastemas are grafted more distally, as proximal‐to‐distal grafts that do not span a limb segment (eg, proximal stylopod to distal stylopod) do not produce such duplications . Together these studies show that, compared to cells of the cockroach leg, cells of salamanders appear to be constrained by the rule of distal transformation so that they cannot contribute to more proximal structures.…”

Photoperiod‐independent testicular development in the model newt Pleurodeles waltl

“…Newts have been especially popular as models of tissue regeneration. Notably, newts possess the remarkable ability to regenerate lost body parts (as reviewed in Agata & Inoue, 2012; Brockes & Kumar, 2002), including limb (Brockes, 1997; Koriyama et al., 2018; Tsutsumi et al., 2015), jaw (Kurosaka et al., 2008), optical tissues (Chiba et al., 2005; Hayashi et al., 2004), heart (Simon & Odelberg, 2015), and brain (Okamoto et al., 2007; Urata et al, 2018). Newts also can regenerate the testis (Flament et al., 2009; Uchida & Hanaoka, 1949).…”