biostudies-literatureStewart SNICHD NIH HHSNational Institutes of HealthNIAMS NIH HHSNIGMS NIH HHSdev199384https://www.ebi.ac.uk/biostudies/studies/S-EPMC8217709biostudies-literatureUnknown148(11)Organs stop growing to achieve a characteristic size and shape in scale with the body of an animal. Likewise, regenerating organs sense injury extents to instruct appropriate replacement growth. Fish fins exemplify both phenomena through their tremendous diversity of form and remarkably robust regeneration. The classic zebrafish mutant longfint2 develops and regenerates dramatically elongated fins and underlying ray skeleton. We show longfint2 chromosome 2 overexpresses the ether-a-go-go-related voltage-gated potassium channel kcnh2a. Genetic disruption of kcnh2a in cis rescues longfint2, indicating longfint2 is a regulatory kcnh2a allele. We find longfint2 fin overgrowth originates from prolonged outgrowth periods by showing Kcnh2a chemical inhibition during late stage regeneration fully Development (Cambridge, England)longfin causes cis-ectopic expression of the kcnh2a ether-a-go-go K+ channel to autonomously prolong fin outgrowth.PMC8217709F31 AR071283F31 GM139343F31GM139343T32 HD007348T32 GM007413F31AR071283R03 AR067522R01 GM127761R01GM127761Yette GARobbins AEStewart SBraunstein JAStankunas KLe Bleu HKHenner ALfalselongfin causes cis-ectopic expression of the kcnh2a ether-a-go-go K+ channel to autonomously prolong fin outgrowth.Organs stop growing to achieve a characteristic size and shape in scale with the body of an animal. Likewise, regenerating organs sense injury extents to instruct appropriate replacement growth. Fish fins exemplify both phenomena through their tremendous diversity of form and remarkably robust regeneration. The classic zebrafish mutant longfint2 develops and regenerates dramatically elongated fins and underlying ray skeleton. We show longfint2 chromosome 2 overexpresses the ether-a-go-go-related voltage-gated potassium channel kcnh2a. Genetic disruption of kcnh2a in cis rescues longfint2, indicating longfint2 is a regulatory kcnh2a allele. We find longfint2 fin overgrowth originates from prolonged outgrowth periods by showing Kcnh2a chemical inhibition during late stage regeneration fully 2021-01-01T00:00:00Z2021 Jun2026-05-09T04:19:25.869Z2025-04-04T22:04:06.439ZS-EPMC82177093406117210.1242/dev.199384