Tail regression in Ciona intestinalis (Prochordate) involves a Caspase-dependent apoptosis event associated with ERK activation.
Two apoptotic events take place during embryonic development of Ciona intestinalis. The first concerns extra-embryonic cells and precedes hatching. The second controls tail regression at metamorphosis, occurs through a polarized wave originating from tail extremity, and is caspase dependent. This was shown by: (1) in vivo incorporation of a fluorescent marker of caspase activation in different cell types of the tail; (2) detection of an activated form of caspase 3-like protein by western blotting; and (3) failure of 30% of larvae to undergo metamorphosis after treatment of fertilized eggs with a pan-caspase inhibitor. In addition, Ciona embryos express a single ERK protein, specifically phosphorylated at metamorphosis. ERK activation was shown to be located in cells of the tail. Addition of MEK inhibitor in the culture medium prevented ERK activation and metamorphosis. In silico analysis of Ciona genome pointed to 15 caspases with high homology with humans, and a single ERK gene with high homology to both mammalian ERK1 and ERK2. It is concluded that the sequence of events leading to metamorphosis includes ERK phosphorylation followed by caspase-dependent apoptosis and tail regression.
Chambon
Jean-Philippe
JP
UMR 5539 Centre National de la Recherche Scientifique, Dynamique Moléculaire des Interactions Membranaires, Université Montpellier II place E. Bataillon 34095 Montpellier cedex 05, France.
Soule
Jonathan
J
Pomies
Pascal
P
Fort
Philippe
P
Sahuquet
Alain
A
Alexandre
Daniel
D
Mangeat
Paul-Henri
PH
Baghdiguian
Stephen
S
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism*; D002938:Ciona intestinalis / Q000196:embryology / Q000235:genetics / Q000254:growth & development*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004625:Embryo, Nonmammalian; D005260:Female; D006801:Humans; D007814:Larva / Q000187:drug effects; D008297:Male; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D017386:Sequence Homology, Amino Acid; D013623:Tail / Q000196:embryology / Q000254:growth & development* / Q000473:pathology; D014404:Tubulin / Q000378:metabolism
D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D014404:Tubulin; D020929:Mitogen-Activated Protein Kinase Kinases; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases