FGF2 triggers iris-derived lens regeneration in newt eye.
Lens regeneration in newts occurs exclusively from the dorsal aspect of the iris pigment epithelium. Although the phenomenon has been a paradigm of experimental tissue regeneration, little is understood about how it is initiated and restricted to the dorsal iris. Here we show among various growth factors injected in an intact eye, a single injection of FGF2 specifically caused morphological changes of the iris characteristic of lens regeneration, induced expression of transcription factor genes Pax6, Sox2 and MafB, as well as endogenous Fgf2 in both dorsal and ventral halves, and provoked second lens development only from the dorsal iris. FGF2 protein accumulated in the iris tissue after the lens was removed, and injection of a soluble form of FGF receptor titrating FGF2 inhibited all reactions observed after the lens removal or after administration of FGF2. These results indicate that FGF2 and/or related molecules trigger lens regeneration from the dorsal iris in the newt. The observations also indicate that the absence of lens regeneration from the ventral iris is due to a block in a later phase of lens developmental pathway.
Hayashi
Toshinori
T
Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.
Mizuno
Nobuhiko
N
Ueda
Yoko
Y
Okamoto
Mitsumasa
M
Kondoh
Hisato
H
D000818:Animals; D001973:Bromodeoxyuridine / Q000494:pharmacology; D049109:Cell Proliferation; D004396:Coloring Agents / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000378:metabolism; D005136:Eye Proteins; D016222:Fibroblast Growth Factor 2 / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D024002:HMGB Proteins; D006609:High Mobility Group Proteins / Q000378:metabolism; D018398:Homeodomain Proteins / Q000378:metabolism; D007150:Immunohistochemistry; D007498:Iris / Q000378:metabolism*; D007908:Lens, Crystalline / Q000254:growth & development / Q000502:physiology*; D051258:MafB Transcription Factor; D009687:Nuclear Proteins / Q000378:metabolism; D015513:Oncogene Proteins / Q000378:metabolism; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D010766:Phosphorylation; D012313:RNA / Q000378:metabolism; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism; D012038:Regeneration; D012097:Repressor Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055748:SOXB1 Transcription Factors; D012455:Salamandridae; D013997:Time Factors; D014018:Tissue Distribution; D014157:Transcription Factors / Q000378:metabolism; D025521:Tumor Suppressor Proteins; D029867:Xenopus Proteins / Q000378:metabolism; D000098551:Prospero-Related Homeobox 1 Protein
D004396:Coloring Agents; D004268:DNA-Binding Proteins; D005136:Eye Proteins; D024002:HMGB Proteins; D006609:High Mobility Group Proteins; D018398:Homeodomain Proteins; D051258:MafB Transcription Factor; C490406:Mafb protein, mouse; D009687:Nuclear Proteins; D015513:Oncogene Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; C000605732:Pax6 protein, mouse; D017468:Receptors, Fibroblast Growth Factor; D012097:Repressor Proteins; D055748:SOXB1 Transcription Factors; C490905:Sox1 protein, Xenopus; C527783:Sox2 protein, mouse; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D029867:Xenopus Proteins; D000098551:Prospero-Related Homeobox 1 Protein; C527781:sox2 protein, Xenopus; D016222:Fibroblast Growth Factor 2; D012313:RNA; D001973:Bromodeoxyuridine