The salamander king

When assis­tant pro­fessor of biology James Mon­aghan was an under­grad­uate, he hung a life-​​size inflat­able Spi­derman from the ceiling of his dorm room. The plastic incar­na­tion of the super­hero fol­lowed him all the way to his new lab here at North­eastern. His obses­sion with the "genius kid-​​scientist" earned Mon­aghan the nick­name "Spi­derman," and it stuck until grad­uate school, where he found a new obses­sion: salamanders.

Like the Lizard, the vil­lain in the most recent Spi­derman movie, Mon­aghan is a biol­o­gist inter­ested in spinal cord and limb regen­er­a­tion, for which sala­man­ders have become known. In par­tic­ular, Monaghan's research cen­ters on the axolotl (AK'–suh–lot-​​l) sala­mander, which can regrow an arm, foot, or even parts of its brain in near-​​perfect fashion.

Mon­aghan ana­lyzes the genomes of axolotls in an attempt to iden­tify fac­tors that are required for regen­er­a­tion. If the same genes are present in humans but are simply not turned on during wound healing, he posits, then it is plau­sible to con­sider a future in which human limb regen­er­a­tion is feasible.

While doing research as a post­doc­toral stu­dent at the Uni­ver­sity of Florida, Mon­aghan and his col­leagues pub­lished a one-​​of-​​a-​​kind paper in which they pre­sented a genet­i­cally engi­neered sala­mander that glows green when its retinoic acid pathway is active. Retinoic acid is a sig­naling mol­e­cule that seems to be impor­tant for regen­er­a­tion. By allowing labs to see retinoic acid activity, Monaghan's team cre­ated an impor­tant tool for the field.

Mon­aghan intends to con­tinue devel­oping sim­ilar tools in his research lab at North­eastern. "The next step is to gen­erate ani­mals that can express reporters and genes in spe­cific tis­sues at spe­cific times," he said.

The ques­tion of limb regen­er­a­tion has puz­zled sci­en­tists as far back as Aris­totle. In 1768, one of the fathers of exper­i­mental biology, Laz­zaro Spal­lan­zani, won­dered why other ani­mals "are not endued with the same power" as sala­man­ders. "Is it to be hoped they may acquire them by some useful dis­po­si­tion?" he asked. "Should the flat­tering expec­ta­tion of obtaining this advan­tage for our­selves be con­sid­ered entirely as chimerical?"

"[The quo­ta­tion is] a great example of how many ques­tions we ask in biology are not new, such as how ani­mals develop or regen­erate," said Mon­aghan, who sus­pects that the renais­sance of regen­er­a­tive biology in pop­ular cul­ture reflects the mat­u­ra­tion of the field. "The exciting part is that we just now have the tools to prop­erly address them."