Zebrafish are a type of minnow widely used in scientific research. Small, semi-transparent freshwater fish, they reproduce rapidly and their transparent embryos develop outside the body. Such traits are helpful for viewing biological processes within the embryo or adult tissues.
What does it take to regenerate a limb? When a zebrafish loses its fin, a special group of cells forms on the remaining stump. These cells, which appear identical to one another, regrow the entire limb, complete with all cell types required for a complex organ. This has suggested that these cells may be “pluripotent” stem cells, capable of forming almost every tissue in the body.
To determine if this was indeed the case, Johnson and postdoctoral research associate Shu Tu, PhD, who did this work for her doctoral thesis, used genetic techniques to label individual cells in the stump with a fragment of DNA that makes the cells glow green. When a cell divides, it copies its DNA so that each daughter cell has a complete set of genetic material. Since Johnson and Tu’s label is inserted into the cell’s DNA, the cells also duplicate the label and pass it on to each daughter cell. By simply observing which cells glow green, Johnson and Tu could track the subsequent daughter cells and determine what cell types they become.
For example, they saw that when they had glowing skin cells in the stump, only skin cells glowed in the regenerated limb. Likewise, when a nerve cell glowed in the stump, only nerve cells glowed in the regenerated limb. In other words, they saw no evidence that a skin cell glowing in the stump could give rise to a nerve cell glowing later in the fin’s development or regeneration.
Using this technique, Johnson and Tu identified nine separate cell lineages present at the end of the stump that contribute to forming the fin’s skin, nerves, pigment, blood vessels, bone and immune cells.
The study appears online May 16 in Developmental Cell.
Tu, S. and Johnson, S.L. Developmental Cell (2011) 20; 725-732.
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Selected antibodies that recognize Zebrafish specific proteins
|A0906-51||Adrenergic Receptor, Alpha 1 (A1AR)|
|A1124-02P||Akt, phosphorylated (Ser473) (Rac PKa, PKBa)|
|A1124-02Q||Akt, phosphorylated (Ser473) (PE)|
|C1035-25B2||Calmodulin-Dependent Protein Kinase II, alpha (CAMKII)|
|C2069-47J||Catenin, beta, phosphorylated (Ser675)|
|C7915-80||CREB Regulated Transcription Coactivator 1|
|D3931-63C||DNA Methyltransferase 1|
|F0019-63M1||Fas (CD95, APO-1) (Biotin)|
|F4150-34A||FK506 Binding Protein 12-Rapamycin Associated Protein 1 (FRAP1, FLJ44809, RAFT1, RAPT1)|
|L9058-02C||Lysine, Acetylated (Acetyl-Lysine)|
|M2352-05H||MAP Kinase, p38, phosphorylated (Thr180/Tyr182)|
|M2352-20C||MAP Kinase p44/42, phosphorylated (Thr202/Tyr204)|
|M2352-20D||MAP Kinase p44/42, phosphorylated (Erk1/2) (Thr202/Tyr204)|
|M2352-20E||MAP Kinase p44/42, phosphorylated (Erk1/2) (Thr202/Tyr204)|
|M2352-20N||MAP Kinase p44/42, phosphorylated (Thr202/Tyr204) (PE)|
|M2355-01A||MAPKAP Kinase 2|
|N2150-12||Neurofibromin 2 (Zebrafish)|
|P3105-77D||PAR4 (Proteinase Activated Receptor 4)|
|P4480-48||Polyubiquitin, Lysine 48-Linkage Specific|
|R1426-11A||RelB, phosphorylated (Ser552)|
|S1014-53H1||Smad3 (Small Mothers Against Decapentaplegic Deleted in Pancreatic Carcinoma)|
|S6500-06E||Src, phosphorylated (Tyr416) (pp60Src, pp60c-Src)|
|T5348-98Y||Thyroid Hormone Receptor, alpha (THRa)|
|T9154-01C||Tubulin, alpha, acetyl (Lys40)|
|T9155-04C||Tubulin, beta (HRP|