Regulation of polyp-to-jellyfish transition in Aurelia aurita.
BACKGROUND
The life cycle of scyphozoan cnidarians alternates between sessile asexual polyps and pelagic medusa. Transition from one life form to another is triggered by environmental signals, but the molecular cascades involved in the drastic morphological and physiological changes remain unknown.


RESULTS
We show in the moon jelly Aurelia aurita that the molecular machinery controlling transition of the sessile polyp into a free-swimming jellyfish consists of two parts. One is conserved and relies on retinoic acid signaling. The second, novel part is based on secreted proteins that are strongly upregulated prior to metamorphosis in response to the seasonal temperature changes. One of these proteins functions as a temperature-sensitive "timer" and encodes the precursor of the strobilation hormone of Aurelia.


CONCLUSIONS
Our findings uncover the molecule framework controlling the polyp-to-jellyfish transition in a basal metazoan and provide insights into the evolution of complex life cycles in the animal kingdom.
Zoologisches Institut, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany; Leica Microsystems AG, Max Schmidheiny Strasse 201, 9435 Heerbrugg, Switzerland.
Björn
B
Fuchs
Zoologisches Institut, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany.
Wei
W
Wang
Zoologisches Institut, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany.
Simon
S
Graspeuntner
Zoologisches Institut, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany.
Yizhu
Y
Li
Zoologisches Institut, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany.
Santiago
S
Insua
Zoologisches Institut, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany.
Eva-Maria
EM
Herbst
Zoologisches Institut, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany.
Philipp
P
Dirksen
Zoologisches Institut, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany.
Anna-Marei
AM
Böhm
Institut für Klinische Molekularbiologie, Universitätsklinikum Schleswig-Holstein, Schittenhelmstrasse 12, 24105 Kiel, Germany.
Georg
G
Hemmrich
Wallenberg Laboratory for Cardiovascular and Metabolic Research, Sahlgrenska University Hospital, University of Gothenburg, 413 45 Gothenburg, Sweden.
Felix
F
Sommer
Institut Ruđer Bošković, Bijenička cesta 54, 10000 Zagreb, Croatia.
Tomislav
T
Domazet-Lošo
Institut für Klinische Molekularbiologie, Universitätsklinikum Schleswig-Holstein, Schittenhelmstrasse 12, 24105 Kiel, Germany.
Ulrich C
UC
Klostermeier
Zoologisches Institut, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany.
Friederike
F
Anton-Erxleben
Institut für Klinische Molekularbiologie, Universitätsklinikum Schleswig-Holstein, Schittenhelmstrasse 12, 24105 Kiel, Germany.
Philip
P
Rosenstiel
Zoologisches Institut, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany.
Thomas C G
TC
Bosch
Zoologisches Institut, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany; Department of Invertebrate Zoology, Saint Petersburg State University, Universitetskaya naberezhnaya 7/9, 199034 Saint Petersburg, Russia. Electronic address: konstantin.khalturin@oist.jp.
Konstantin
K
Khalturin
D000818:Animals; D006728:Hormones / Q000502:physiology*; D017403:In Situ Hybridization; D008018:Life Cycle Stages / Q000502:physiology*; D008675:Metamorphosis, Biological / Q000502:physiology*; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D037401:Scyphozoa / Q000254:growth & development*
D006728:Hormones